Russ Roberts

Taubes on Why We Get Fat

EconTalk Episode with Gary Taubes
Hosted by Russ Roberts
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Gary Taubes, author of Why We Get Fat, talks with EconTalk host Russ Roberts about why we get fat and the nature of evidence in a complex system. The current mainstream view is that we get fat because we eat too much and don't exercise enough. Taubes challenges this seemingly uncontroversial argument with a number of empirical observations, arguing instead that excessive carbohydrate consumption causes obesity. In this conversation he explains how your body reacts to carbohydrates and explains why the mainstream argument of "calories in/calories out" is inadequate for explaining obesity. He also discusses the history of the idea of carbohydrates' importance tracing it back to German and Austrian nutritionists whose work was ignored after WWII. Roberts ties the discussion to other emergent, complex phenomena such as the economy. The conversation closes with a discussion of the risks of confirmation bias and cherry-picking data to suit one's pet hypotheses.

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0:36Intro. [Recording date: July 11, 2012.] Russ: Guest is Gary Taubes. His latest book is Why We Get Fat. You were a guest on this program back in 2011 in November, and we talked about your earlier book on a similar topic, which was Good Calories, Bad Calories. This latest book covers some of the same ground, but in a more accessible way. And when we talked about that first book we focused on how public opinion and public policy is shaped by research that you argued was mistaken. And I saw a lot of parallels between that research and the evolution of policy in the area of nutrition and health to research in policy in economics--problems of groupthink, confirmation bias. In this conversation, I want to focus, as the second book in the topic does, on what we know about weight loss and what you might know of the micro side of the weight loss equation and diet and nutrition question. The economics analogy here is the challenge of understanding a complex system, where it's difficult if not impossible to hold one factor constant and isolate the impact of other factors, both in practice and in research. So let's start by asking the fundamental question. It would seem that all we need to know about weight loss in the human body is captured by the slogan: Eat less and exercise more. That would seem to be undeniably true. And in the end of the discussion, if we want to lose weight, we could do one or the other; both ideally; and I think that's what most people try to do when they want to lose weight. They try to eat less and exercise more. And yet your book begins with challenging that conventional wisdom. What do you see as wrong with that simple and seemingly compelling phrase? Guest: Virtually everything. The short answer. I believed in this a decade ago, before I started my research. You can think of obesity in one of two different ways. The less I eat, the more I exercise idea comes out of the research called the energy-balance problem: You take in more energy than you expend, that energy has to go somewhere, so our bodies stick it in the fat tissue and that's pretty much all you have to know. And if you want to get the energy out of the fat tissue you just have to increase your expenditure, decrease your intake, and then your body will take the energy from the fat tissue and burn it. And it's this incredibly simplistic idea that basically comes down to we are some dynamic systems and we could be a black box, for all anybody cares. Doesn't matter what's happening inside. It just matters that more energy goes in, you get fat; you get thin the more energy goes out. And as I was doing my research for my books, I realized that actually this was a hypothesis, and it was a controversial hypothesis up until the 1950s, 1960s. And pre-WWII when all meaningful science in virtually all fields was done in Europe, the Europeans had a different conception of what caused obesity. And they thought of it as a sort of hormonal regulatory defect, just like any other growth disorder. And so you have your fat tissue is regulated by a whole complex system of hormones and enzymes and receptors and other central nervous system factors, and if that regulation gets out of whack you will start getting fatter. And if you start getting fatter, if your fat tissue starts growing, you'll take in more energy than you expend. So, dysregulation of the fact tissue is the cause, and this disturbance in energy balance is the effect, in this kind of pre-WWII way of looking at it. And the problem is, WWII comes along; the European and German and Austrians in particular, their school of research on this evaporates. Unlike physics, where we embraced all the European scientists who were chased to the United States, in medication and public health we wanted nothing to do with them. And post WWII this idea vanishes. And it's replaced with an idea of obesity as an eating disorder and basically gluttony and sloth. And what I did in my research was say: If this idea was right, if the Germans and Austrian researchers who were pushing this hormonal defect notion were right, how would the world have played out since then? And you see by the late 1950s, early 1960s, researchers, physiologists, and biochemists figure out what would regulate fat tissue, and it turns out to be fundamentally the hormone insulin that puts fat in our fat tissue. And as soon as you've identified insulin as the culprit, then it's the carbohydrates in our diets that determine insulin levels, independent almost of total calories. And now you've got a hypothesis of obesity that carbohydrates make you fat. And they do it by raising insulin levels. Not total calories. Russ: Which in turn, those higher insulin levels cause fat from our diets to enter into our bodies--is that the right way to think of that puzzle? Guest: Well, that's one way. When you eat a mixed meal, the fat from the meal gets stored in your fat tissue. And this is one of reasons why people always wanted to blame obesity on dietary fat. So, when you eat a mixed meal with fat, protein, carbohydrates, your body wants to burn off the carbohydrates because they get dumped into your bloodstream as glucose. Your glucose is blood sugar; your blood sugar levels start to rise. This has toxic effects to various cells. You secrete insulin in part to control your blood sugar. And one of the ways it does it is that it facilitates the entry of the glucose into your muscle cells so they can burn it. But it also locks the fat away in your fat tissue. Kind of saying: We'll deal with the fat later; let's burn the carbs now. And then when glucose levels start coming down, insulin levels start coming down. The fat is released from the fat tissue and the muscle tissue starts to oxidize it for fuel. And in an ideal world you've got a system where you eat a meal, you store fat, you burn carbs; you burn through the carbs, now you start to burn the fat, now you've gotten your fat back down to where it was originally; you get hungry and eat again. So, it's a beautifully orchestrated system, and it's this hormone insulin that runs it all. But if insulin signaling starts getting out of whack--and the idea is that the kinds of carbohydrates we eat today are new to our species, from brand new to relatively new to brand new--and we haven't evolved to deal with them, and they cause various disorders that are signaling in effect to keep insulin high; and if you are keeping insulin high you are keeping fat locked up in the fat tissue rather than burning it. And you end up in this system where sort of every day you store a little more fat than you should. And even if it's the dietary fat that's being stored, it's the carbohydrate content that the diet that's causing the effect. And this is all just sort of basic 1960s level endocrinology and physiology. And one of my challenges as a journalist and someone writing about this, and now kind of a proponent of this idea, is to get across the idea that we actually solved the obesity epidemic in the 1960s. And all we needed was 1960s-era medicine to do it. And technology to do it. And the problem is we decided that solution wasn't convenient. And we threw it out and decided to ignore it. And that's when we get to the situation we've been in ever since.
9:08Russ: So, if I eat lots of calories and watch a lot of television and sit on my couch, but the kind of calories I eat are protein-oriented and vegetables that are not starchy, and therefore I have low carbohydrates, you are suggesting that I will not get fat. Guest: Yeah. Although I would edit that to say that if you are eating--actually, what you want to eat is a moderate protein, high fat diet. Fat is the one nutrient that does not trigger insulin secretion. So if you are already overweight, obese, or Type 2 diabetic, protein levels in the diet should also be kept relatively low. Although you could eat a meat-rich diet and still not get a lot, 15-20%, of your calories from protein. But yeah, the idea is, you could be sedentary, you could eat a lot, and if you don't have these offending carbohydrates in your diet, your body will metabolize the energy that you take in, and it will do it perfectly fine, and it will not just stick it in your fat tissue and make you fat. That's an idea that's exceedingly hard for the establishment researchers to buy or understand. Russ: And similarly, you are going to argue that if I have a low calorie diet of, say, being a male, 57 years old, if I eat 1500 or 1800 calories per day, but they are potatoes, candy bars, and bread, I can be obese despite my low-calorie intake. Guest: Yeah. And again, one of the things I do in Why We Get Fat, the very first chapter includes a list of populations that had high levels of obesity, coincident with extreme poverty. I just did something that I always felt the research community themselves should have done but never bothered. We have this idea that it's the toxic environment we live in today that causes obesity. So that toxic environment is fast food joints on every corner, large portion sizes, energy-dense foods--whatever that means--and there is no reason to be physically active, so we don't let our kids walk to school any more; we are always getting in the car; we don't even roll down our own windows any more. And so we have this combination of too much food, it's too available, it's huge portion sizes, not enough reason to be physically active; and that's why we get fat. And what I did was I just looked for counterexamples. Which to me is basic science. Let's look to see if we can find basic populations that had high levels of obesity and had none of this toxic environment. And I found about a dozen of them. I probably found most of the ones that have been studied but I wouldn't be surprised if there are papers in journals here and there that identified others. These go back to the Pima Indians in 1902, where a Harvard anthropologist who lived with the Pima for 6 months, wrote the seminal text on them. The Pima had gone through 20 years of famine from the 1870s, 1880s, early 1890s. And here they were half a dozen years out of their famine period; they are on a government reservation. And Frank Russell, this anthropologist comments about the high level of obesity in the tribe. And he has a photo of an obese Pima woman in his book, which was published in 1905, 1906, and he calls her 'Fat Louisa.' And he points out, as did another Smithsonian anthropologist who traveled to the area, that most of the obesity is in the women and the women work--they were basically treated like beasts of burden. They did most of the farming; they carried anything that the tribe wasn't loading on mules or horses. So if physical activity is a way to prevent obesity--and this is what this Smithsonian anthropologist, who went on to become Head of Physical Anthropology at the Smithsonian, commented--was that if physical activity made a difference, why is it that the women are fat when the women did far more work than the men did? And you see this same trend in 1928 with reservation Sioux on a South Dakota Crow Creek Reservation--very high levels of obesity in coincidence with extreme poverty. Deficiency diseases. In the early 1960s, studies in Trinidad--MIT nutritionists calculated that the diet was giving no more than 2000 calories per day and it was 21% fat and yet they described the obesity problem among the females as an extreme medical problem. And it goes on. Chile in construction workers in the 1960s. Mexican-American oil field workers in the 1980s. And these are poor, hard-working people, sometimes living on near starvation levels of food and yet still with high levels of obesity. So the question I ask in the book is the question I think everyone should ask: Why were they fat? Because if we could figure out what made those populations fat we'll probably have the answer to what makes us fat. And what we know is that they didn't have computers, they didn't have video games, they didn't have iPads, cars, any kind of labor-saving devices. And in some cases they worked a lot harder than any of us ever do. So, what was going on to disregulate their fat tissue? And the answer is? Guest: One thing that was common to all these populations is they were relatively new to refined grains, like white flour and sugar. Even the Pima--trading post comes into the Pima territory after the 1850s and the trading posts are selling sugar and white flour. And the Pima are living on government rations, and 50% of the government rations actually are mostly white flour and some sugar. So again you can argue that you add these refined grains and sugars to a population, you are going to get obesity, diabetes, diseases that associate with them. And the problem with our toxic environment today is not that we don't get enough physical activity, it's not that there's too much saturated fat or anything else, but that there's too much sugars and refined grains in our diets. And if you get rid of those, which is what you do fundamentally on a low carb diet, you reverse the problem.
16:40Russ: When I read your book, I admit I heard that argument, but I heard a subtler version of what's wrong with calories in, calories out that I found extremely interesting and it reminded me a lot of the economic way of thinking. So I want to take a couple of examples from the book and you can talk about how they relate to endocrinology and what's going on in the body. So, you have a fascinating example. You have a picture of your son and, as you point out, most kids eat a lot when they are growing. And we would never say: Oh, my kid's growing because he's eating more than he exercises, so therefore he's able to grow. We say: He's having some kind of hormonal growth spurt and as a result, he's hungry. And so causation isn't just complicated. It's actually the opposite of the way we often think about the relationship between eating and obesity. With eating and obesity we tend to think: Well, I eat too much so I get fat. In fact, there's an argument to be made that because I'm fat, I eat a lot. I'm hungry, I have an urge to eat. And the psychological part of that that I find interesting, and I think this varies a great deal by individual, at least I presume it does--we can talk about that--but I know for myself, the line about you can't just eat one potato chip, which was a marketing slogan, is very true for me. It's not just that it's hard to eat one. There's no number of potato chips that satiate me. There's no number of French fries where if someone said, have another plate, that I would say: No, no, they don't appeal to me; I've had plenty. They are always appealing to me--when I've had some. When I don't eat them they are still appealing but in a different way than if I've had a few. And so that causal relation appears to be the opposite of what actually is the way we tend to think about it. Guest: There are a lot of examples of this that I point out in the book. The growing child--and here again, I'm just channeling the way the pre-WWII Germans and Austrians thought about this problem--and the growing child was one of their metaphors. An argument that I make in the book is that in every growth system that you can imagine, growth is the cause. And an increase in intake of nutrients is the effect. So in the growing child, the child's brain, pituitary gland is secreting growth hormone; the growth hormone is stimulating an insulin-like growth factor, and those are driving the growth of cells and tissues; and compensating for this, the body then needs more energy to both build these tissues and for the energy required for the building. And so the kid is hungry. And often you hear the same thing when your children are growing that they are lying around the house all day long: My son is eating me out of house and home and he's lying around the house all day long, and the reason he is doing that is he is going through a growth spurt and that growth spurt is driven by hormones. Elephants eat more than puppy dogs. And the reason they do--young elephants eat more than young dogs--and the reason they do is they are growing bigger. So, any system you can imagine. When a tumor is growing, that tumor is taking in more energy than it expends, but we don't really care that that's why--it's obvious that it's taking in more energy than it expends because it's growing. What we care about is what genes, oncogenes, tumor suppression genes in that tumor are broken that are driving it toward this unfettered growth. And the fact that if we could cut off the fuel supply to the tumor we could kill it is irrelevant. It doesn't mean that it's the excess fuel that's driving the growth. It means the growth is creating a sort of excess demand for fuel and the tumor--part of what's happening with the mutations that drive the tumor growth are all these mutations that allow it to take in more fuel from its environment to fuel the growth. So the fundamental argument I'm making is obesity is, we should think of it the same way. The reason people are hungry, the reason they tend to eat more when they are getting fatter is because the foods they are eating are stimulating the growth of their fat tissue. Those potato chips, the French fries, they stimulate insulin secretion. The insulin stimulates fat accumulation in the sense that it starts storing all the excess glucose, fatty acids in your bloodstream and locking them away in your fat tissue. So your fat cells are expanding. And the rest of your body perceives that as a kind of absence, relative dearth of metabolic fuels to run the body. And so you respond by wanting to continue eating or to eat more. The French have this wonderful phrase, that the appetite comes with the meal. And you've probably thought about this--I think about this--you might sit down to a meal and not be hungry, and then once you have a few bites of the appetizer, which is often a carb-rich creation, created to stimulate your appetite-- Russ: Yeah, it's called an appetizer-- Guest: For a reason. Yeah. And then suddenly you are hungry. Even though you would think that with each successive bite you would get more satiated and less hungry, that's not actually what happens. For a large portion of the meal you are hungrier than you were before you started eating. So there are all these hormonal factors that regulate this. And what you end up with is just a process of flipping the causality in obesity. I'm always having conversations with people where they are arguing, well certainly there's all kinds of psychological factors that are involved. For instance, I get stressed, I eat more; I get happy, I eat more; I get unhappy, I eat more. But among the things that are happening--for instance, if you got stressed and ate more fat and protein--so you went to the refrigerator and had a piece of rib eye instead of potato chips or pasta, then even though you are stressed you wouldn't get fatter. That's the argument. And then you ask the question: Why is it that when you get stressed, the foods you want, you know, comfort foods, are always rich in carbohydrates--usually sugars? And it turns out that stress hormones also have an effect on fat tissue, on fat cells. And in some ways they are similar to insulin and they work in collaboration with insulin in some ways, and so you could argue that it's the effect of the stress hormones on the fat tissue that in turn makes you crave the carbohydrate-rich comfort foods that calms you down. But the behavior in this sense is always an effect. Our null hypothesis, the assumption going in, is that the behavior is a response to a change in the physiological state of the body. Not a driver of that physiological state.
24:30Russ: Let me take a couple of examples here, to bring in a little of the economics. First I'm sure our listeners have noticed that there was a failure to pay attention to Austrian scientist and researchers after WWII. Which is of course true in economics as well. This program has an Austrian flavor because of my deep interest in the work of Friedrich Hayek. Guest: Have you've ever read Siddhartha Mukherjee's brilliant book, The Emperor of All Maladies? Russ: No. Guest: I'm a passive aggressive competitive science journalist. I don't like to call anyone's book 'brilliant' if I can avoid it, but it's really a remarkable book, and it's a history of cancer and cancer research. And this theme just keeps repeating itself, with research done in Europe mutually by Germans and Austrians in the 1920s that just gets ignored and/or forgotten, in part because of the disruption that Europe goes through in the war. And then is finally reconstituted in the United States, you know, in the 1950s, 1960s, even the 1970s in some cases. Russ: It's also a bias against German accents probably. I mean, F. A. Hayek's video presence is not easy to access, because he's not as articulate as John Maynard Keynes. So what can you do? Guest: And it's certainly true--I talk about this in the obesity field. The leading American expert on obesity post WWII was Jean Mayer, who was a French émigré. He had fought in the French resistance, and he simply refused to reference the German research in any of his books. And one of his colleagues told me that: Oh, yeah, Jean Mayer, he hated the Germans; he killed quite a few of them. And my metaphor is, imagine if in physics, instead of embracing these European researchers because we had atomic bombs to build and cold wars to fight, imagine if they had said: We don't care what that Heisenberg fellow had to say or Bohr or Planck or Einstein; what could they tell us? We don't like their accents; we fought a war against them; we don't like their politics; we don't like their attitude. And so we are going to ignore everything they did. And this is what happened in medicine and public health. Russ: So, the other example I wanted to mention is this causation being reversed. One of the strangest things to me is this belief that spending creates prosperity. When in fact I think causation is reversed. It is prosperity that allows spending. But because they happen at the same time, we've come to believe that by spending money with each other we can somehow stimulate economic activity and productivity, when I think what we really want to do is stimulate productivity and that allows us to spend and have a nice standard of living. Now the other examples that you give in the book that are so provocative, besides the growing child--I want to go through a couple more of those before we get to some of the, I want to challenge some of your arguments. But I want to go through some of the metaphors first. You talk about a remarkable experiment. The ovaries are removed on one set of rats and not on the others, and what happens, and how we could have misinterpreted that. Talk about that example. Guest: Well, this is one of the seminal examples that I came upon in my research, where I began to have my paradigm shifted. And this is research done at the U. of Massachusetts in the mid-1970s by someone named George Wade. And George is only interested in reproduction. And so he was studying the effect of female sex hormones on weight gain and reproduction. And he did these experiments where he removed the ovaries from rats, females obviously, and noticed that after the surgery they would get what's called 'hyperphagic'--they would get these voracious appetites and they would quickly grow obese. And effectively what he was doing was removing the estrogen, because if you infused estrogen back into these animals after the surgery, you wouldn't see the hyperphagia and you wouldn't see the obesity. So he said, he's telling me about these experiments: If you do these experiments, if you just do this one experiment, what you think is removing the estrogen, removing the ovaries, works to make the animal hungry, and then that hunger causes the obesity. That eating too much--the hyperphagia. And so you've now confirmed your preconception that eating too much makes people or animals fat. But you could do a second experiment, which he did because he's a good scientist. So now he does the same experiment again--remove the ovaries; but you don't allow the animals to manifest the hyperphagia. You don't allow them to eat any more than they ever did. So you restrict the amount of food they can eat after the surgery to exactly what they were eating before the surgery. And he said to me: What do you think happens? Socratic mode; and I said: I don't know. And it turns out the animals get just as fat, just as quickly. But in the second case they are completely sedentary; actually, their metabolic rate goes down, their body temperature goes down, they expend less energy. And if you only did the second experiment you would imagine that removing the ovaries and the estrogen makes the animal into a couch potato. And they get fat because they expend less energy. But if you do both experiments, what you realize is that removing the estrogen literally makes the animal fatter. It works on the fat tissue and the regulation of fat tissue to increase the accumulation of fat. If the animal can eat more to compensate at will--because now it's losing calories into its fat tissue--so if it can eat more at will. If it can't--if you do the second experiment--it just expends less energy. And what is fascinating about this is you've actually created with this, you've shown in an animal model that the behavior we associate with obesity--gluttony and sloth--can both be effects of the dysregulation of fat tissue. And as Wade explained it to me, what estrogen does is it actually suppresses an enzyme on fat cells called lipoprotein lipase, or LPL. And what LPL does, simplistically putting it, it pulls fat from the bloodstream into whatever cell it happens to be sitting on. So if LPL is on your muscle cell, it pulls fat from the bloodstream in and your muscles burn it for fuel; if it's on your fat cells it pulls fat in and your fat cells store it. And estrogen suppresses LPL on the fat cells. You get rid of the estrogen; LPL blossoms on the fat cells and starts pulling in fat as much as it can. And now the body is sort of suddenly losing all this fuel into the fat tissue. And so it compensates by: you get hungry. And as it turns out, insulin works opposite to estrogen, so insulin actually stimulates LPL all the time. And the argument again is, you change the regulation of the fat tissue. You could do it by removing estrogen; you could do it by increasing insulin--the fat tissue is going to start taking fuel. And the way the pre-WWII Germans referred to it is the fat tissue sort of suddenly has its own agenda. Just like a tumor has its own agenda. It wants to grow and it will take what's necessary from the body to do it. Independent of whatever else the body is doing. Just like a tumor. And then the body has to compensate, because it's suddenly got this drain on its system. So, if it can eat more it does; if it can't it becomes more efficient and gets by with less energy. The cause is the dysregulation of fat tissue; the effect is energy imbalance, taking in more energy than the body expends.
33:00Russ: So, that's one way to think about it. And I struggle to reconcile that with what I heard you say in other parts of the book. So let me bring that out, which is: eating less and exercising more, ignoring the kind of calories you are eating, the kind of food--the mainstream view that says the way you get thin is you change, you just have to make sure you are in deficit and then you'll lose weight--a pound of fat is 3500 calories, is that what it is? So every week that you consume more than you take in, that's 3500, if you can have your deficit be 7000 you'll lose 2 pounds, etc. But what you said in the book, and I think most of us in real life understand this quite well, is that that strategy fails not so much because of the science but because of the behavior. And of course the behavior is driven by the science; maybe that's the source of my confusion. But the way you think about it in the book and the way I think about it in real life is if you are exercising like a fiend, and you are dieting on calories like crazy, you are really unhappy. Your body is not happy; you are really hungry; and as a result, it's very hard to maintain the strategy. So, the strategy is a good strategy. If you can eat 1500 calories a day and run 10 miles, you'll start to lose weight. But that's just not a viable lifestyle over the long run. And that's why it fails. But you also are kind of suggesting it's not just that it fails because of that behavioral reason. It fails because it's literally not scientifically going to hold up. Is it more--what am I confused about here? Guest: That's the idea. You can argue that the dieting--eating as little as you can--and the exercise are both ways to sort of minimize the carbohydrates in your diet. So without even thinking about it, you are reducing the carbs you are taking in. And you are burning off some of the carbs through exercise. So you are changing your fat to your--the fundamental argument I make is if you want to lose fat or your body wants to gain it, you have to change the regulation of your fat tissue. There's a whole suite of forces dominated by insulin that work to store fat in fat tissue and that balance of forces has to change to get the fat out. Now you can change that to some extent by eating significantly less and exercising, running your 10 miles a day, in large part because you are going to reduce the carbohydrates and their driving of insulin and the effect of insulin on the fat tissue. But now you are also increasing the need for dietary fat and for protein to rebuild the muscle tissue and restock that and protein stores. And when you are done with exercising, your fat tissue actually tries to restock the fat that it gave up. Because it's still being driven--you have haven't changed significantly this balance of forces, post-exercise. So your body is now trying to grow again. Your fat tissue is trying to grow. Your lean tissue wants to restore and repair protein, cells that have been broken down by the exercise, and now your body wants the fuel to do it. This, again, very simplistically speaking. So, this hunger that you are trying to live with is a result of what you are doing to your, trying to do by forcing your fat tissue and your lean, forcing your fat tissue to give up calories, not providing your lean tissue with enough resources to rebuild. So, you can have an effect. But that effect goes along with the hunger that is in itself a result of these behaviors. And by the way, there are people out there who have spent their whole lives doing extreme physical activities, from people who work jobs, manual labor, to marathon runners, who despite this continue to get fatter year in and year out. And in fact one of my largest supporters now is one of the world's leading experts on endurance running, who is himself a marathon runner who gained 40-50 pounds over the years despite running 5 or 6 marathons a year. Russ: Just to make an observation again about consuming data and studies, etc. My first thought in listening to make that claim is--but I watch the Olympics coming up in a month or so, and I watch the marathon--everybody there isn't just thin. They are frighteningly thin. Art De Vany, a previous guest on this program would say they are dangerously thin or unhealthily thin or emaciated. They don't look healthy. He argues it's not a healthy thing to run long distances at a constant pace. But I presume your argument would be that I have a selectivity bias, that I see the marathoners who happen to be thin; there are others who are not so thin, but they don't make it into the Olympic trials, so my sample of people who exercise like crazy are only the ones who are able to run very quickly. And it's therefore not a representative sample. Would that be correct? Guest: Yeah. That's exactly it. You could argue that if we all play enough basketball, we'd all become 6'8" and built like Michael Jordan. And odds are that won't happen. The ones who are 6'8" and built like Michael Jordan are the ones we end up watching on television. Russ: Of course, Michael Jordan, now that he's retired, or Magic Johnson, or others who are exercising less than they used to weigh more than they once did. Guest: Quite likely. But one could argue that that weight is not due to their decrease in regular exercise but due to the foods they've been eating and the effect of those foods on their fat regulation.
39:37Russ: You'd have to look at the data. But let me ask a related question to that. I actually--it's hard to believe for those who know me now--I actually ran a marathon and finished it in 1976. It's a long time ago. I concede that. But when I was a semi-serious runner, what I was told to do was carbohydrate loading. So, before the race, I skipped carbohydrates and went heavy protein for a few days, and I think before the race I ate a pound of pasta. I think many athletes are told this--that carbohydrates are energy producers. And so I assume that many world-class athletes are eating a lot of carbs. Is that not true? Guest: Probably. And this is one of the things that actually drove the acceptance of the high carb diet when we were younger. We're within a year of each other. When I grew up, in the 1960s, pasta was something you had once a week. Thursday night was pasta night. And then by the 1980s we were all making pasta every night, and ordering pasta; every time you had a dinner party, pasta is what you would serve because it was easy to cook. Russ: No, it's because Italians are happy. And so we are getting a little causal problem here. Guest: Yeah, well that could do it also. But part of it was driven by the marathon boom, the exercise boom, this idea about carb loading. Russ: No doubt. The energy. Guest: And one of the fascinating things--carb loading was developed by a Scandinavian exercise physiologist, as I understand it for cross country skiers, Olympic cross-country skiers. And these people would train all year round on very low carbohydrate diets and then they would carb-load before. They were raised to maximize the amount of glycogen they could get into their muscles, which, glycogen is the storage form of carbohydrates and it can be beneficial for a lot of endurance activities and actually shorter form burst activities like sprinting. Interesting enough, and this gets us into a different area of discussion entirely, but if you adapt your body entirely to the state of ketosis, where you are burning only dietary fat and you are getting in effect no carbohydrates in your diet, you can do really rather remarkable feats of physical activity. I have a colleague who is now--he eats once a day. He eats dinner, about 3000 calories, no carbohydrates except within the green vegetables. And he's now capable of doing a 90-minute weight workout followed by, for instance, a 70 mile bicycle race the morning after--without eating. And then he still won't eat until dinner the next day. I think it's a little bit obsessive, but he's in effect adapted to the state of ketosis, and even if you've got, say, 6, 8% body fat, which is very lean, you still have enough fat on your body--I want to say if you are 60 pounds at 6% body fat, that's 9 pounds of fat. Russ: Yeah. Guest: So that's--9 times 3500 is--what, about 32,000, 31,000 calories worth of fat to burn? Russ: Yeah. There's plenty there. Guest: That's a lot of exercise that that will fuel. So, if we make progress with the argument we are making, which is the carbohydrates in the diet that are the problem--we are making progress, but if part of this transformation, and the exercise physiologist I mentioned who runs marathons is a South African researcher named Tim Noakes. He's the author of the book The Lore of Running. And Tim is now doing experiments with ketogenic diets on endurance athletes--triathletes, marathon runners--to see how their performance changes when their bodies are running exclusively on fatty acids and ketones instead of glycogen and glucose.
44:10Russ: So I'm going to make a confession now to you and the audience--of which they are actually aware; you are going to be less so--but I'll let you know how this confession informs my questions. Which is that starting back in September of last year, I decided to change my diet and start exercising regularly. The way I changed my diet is during the week I basically have no carbohydrates. I have some on the weekends, but a moderate amount. I've cut out all sugar, all starches, etc. And I lost about 20 pounds. And it's bounced around a little bit around that 20. It's gone down to maybe 15 at one point and now it's about 17 or 18. But I've kept it off for about 10 months, which is a long time for me, and very encouraging. And I want to believe this theory is true. It seems like a good theory. I love the contrarian aspect to it. So, I want to give one more metaphor that you use in the book, to let you explain; and then I'm going to challenge it, even though I do have this deep desire to believe everything you say, Gary. So I have to temper that a little bit. When I tweeted that I was going to be interviewing you people warned me that I need to be careful of my own confirmation bias. Which I'm pretty aware of, but of course, being human, sometimes being aware of it is not sufficient. So, anyway, you give the example in the book, two examples in the book, that are both very provocative, that seem to confirm your antagonism correctly to the calorie-in, calorie-out theory. You show photographs of twins as adults photographed naked so their body types are pretty visible; and one set of twins is really thin, the other set are large and obese. And you make the argument it's hard to believe that these two twins who are both thin just happen to have the same mix of consumption and exercise, and the obese twins, it's hard to believe they just had a different mix but the same for each of them. And similarly you point out that different kinds of cows, there are some cows that are quite fat and some cows that are quite thin. And it's unlikely that the thin cows get a lot of exercise and watch their calories and the fat cows are lazy, watch TV, and gorge themselves at the ice cream bar. But the problem I have with that--and this is where I am trying to challenge my own confirmation bias: Isn't equally hard to believe that those twins had the same patterns of carbohydrate consumption? The same is true for the cows. Isn't a huge portion of what we are talking about genetic? And that I look at families where there is a thin body type member of the parents and a not-so-thin one and they have kids, some of whom are incredibly thin and some of whom spend their whole lives struggling with their weight. And I'm starting to wonder: Maybe this whole carb thing is also wrong. It's just the way I'm born. My body has a certain level of heaviness it wants me to have. I can fight it for a while, but I can't fight it--maybe even for 10 months but I can't fight it forever. I long for those fries. Or, to quote Kingsley Amis: Inside every fat person is a fatter person waiting to get out. That's a great line, isn't it? Guest: Yeah. Russ: So, what's your argument against that genetic argument? Guest: Well, the reason the twins are in there is--obesity has always been known to have a huge genetic component. This was first demonstrated in the 1930s by this Austrian researcher Julius Bauer. The question--you can think of it as a genotype/phenotype issue. We have a certain genetic predisposition that gets triggered by the environment. And some of us have an obese phenotype or diabetic phenotype, and some of us don't. And those of us who do, you ask the question: What is the trigger? We know there's an environmental trigger, because first of all the obesity epidemic and the diabetes epidemic tells us that. The numbers have gone up dramatically in 40 years, 50 years, and that's not enough time for our genetic code to have changed in any significant way. Russ: For sure. Guest: So, something has changed in the environment that's triggered the obese phenotype in more individuals. And then you could just look at other species and say: Why is it that just humans are the only ones who grow chronically obese? So there are hibernators and migrators that put on enormous amounts of fat to migrate or to hibernate or to get through the winters, but they don't become, they don't get the metabolic abnormalities that go with it. They don't become sick. Russ: You have to just make a small correction there, because you haven't seen my cat. You mean, animals in the wild. Guest: Animals in the wild. Very good point. And even elephants, hippopotami, whales that have huge amounts of--actually, elephants, I gather, are not all that fat. A lot of that is just muscle. But the animals that do acquire fat, they are not chronically diseased with it. They don't get heart disease, diabetes. Fat is part of their defense mechanism to survive in their environment. With us we get this obesity as a disease thing. Why? What is triggering it? And so obviously we all have different predispositions to this. One of the arguments I've been making--I didn't make it in the book--you know, I think back to when we were kids. Late 1950s, early 1960s; and there were typically a couple of obese kids, one or two in each year of your school. Russ: Yup. Guest: Your year in school. I was talking to a bariatric surgeon from the U. of Missouri who described himself to me as the fat kid growing up. Back when there was only one. We never saw--when you are kids you don't think of those kids as kids who just eat too much and exercise too little, right? You think of them as people who are different. I'm sure we weren't kind to them. But we didn't think of them as lazy or gluttons. We just thought of them as the fat kids. There was something different about them. So the question just becomes, because we had less obesity 50 years ago, because you could find populations in which obesity didn't exist, because we can't find species in the wild that get obese--only humans and our pets and farm animals--what is it that's triggering that obesity? What is it that triggers the obese phenotype in those of us whose genotype is predisposed to it? And the rational argument, the conventional wisdom is it's too much food available, not enough exercise. And I'm arguing that that's wrong and that the null hypothesis should be the quality and quantity of carbohydrates in the diet. And again, in support of what I'm arguing, until the 1960s the conventional wisdom was that carbohydrates were inherently fattening. Jean Brillat-Savarin, 1825 book The Physiology of Taste, said: I've done conversations with hundreds and hundreds of fat people and they are the ones who want to eat the potatoes, the rice, the bread, the sweets, the beer. As late as 1963 I have a quote that I use in both my books from one of the two leading British dieticians. First sentence of his article in the British journal of nutrition was: Every woman knows that carbohydrates are fattening. And actually, when the 1980s came around and the British government started thinking about pushing low-fat diets for heart disease, one of their reports says we're going to have to figure out a way to get people to eat more carbohydrates when we've been telling them for the last 20, 30 years to eat less because they are fattening. So the argument I am making is it should be the null hypothesis, it should be the hypothesis that requires remarkable evidence to throw out. Particularly because the biochemistry and physiology supports it completely. And then we have this simple fact, as you've experienced, that when you actually do give up the carbs in the diet and replace them with fat, it's, for most of us, almost effortless to lose weight. Except for the French fries craving.
53:29Russ: Yeah. I guess the flip side of that, though, is that if you start to indulge a little bit, and then a little bit becomes a little bit more, your body gets very excited about the arrival of those carbs. Guest: Well, I'm considered a hard-liner on this because I suspect for most of us it's easier not to eat any carbohydrates than it is to eat them in moderation. Russ: That's why it's easier to eat zero of something than a little bit. There's something ironic about that, I suppose. But maybe not. I think everybody understands that. Guest: I used to be a smoker. And if I tried to do what you do with carbohydrates with smoking--like I'm only going to smoke on weekends--I might have been able to do it, but the weekdays would be torture. Russ: Yeah. I don't find it hard. But I'm not so sure it's good for me. I think there's some evidence that this kind of on and off is not so good for you. But I want to come back to the twins. So, I've got these really skinny twins; they're grownups now. They grew up perhaps together; I don't know if they grew up in the same house or not; I think they probably did. And there's one set that's really skin; and both twins are really skinny. And there's one set that's really obese, and both are really obese. Are you suggesting that the obese twins had the predilection toward obesity and then just carbed out? Guest: Well, I'm saying they both lived in an environment where carbohydrates were available and a consistent part of the diet, and it triggered obesity in the obese twins. Not in the lean twins. It's not necessarily a one-to-one correspondence. Like if I eat 55% of my diet from carbs and 15% from sugar and my twin eats 57% carbs and 17% total calories from sugar, that twin is going to be 2% heavier. Russ: That's not true. Guest: That's a kind of simplistic way to think about it. Although I've seen those kind of analyses in the literature with populations where because you don't have a 1-to-1 correspondence between carbohydrate availability or sugar consumption, sugar availability in weight in the population, therefore this refutes the hypothesis. What I am saying is if both of them live in a carb-rich environment, they are both eating from it, they will end up at effectively the same obese bodies. And the lean twins who can tolerate the carbs will tolerate it equally well even if they have subtle differences in how much they consume. Russ: So, to take another weakness of mine, a donut--very hard for me to eat, say, half a donut. I'm more likely to have four. And yet it seems to me there are some people who can take it or leave it. Donuts. And there are others more like me, who have struggled to eat a half and are more likely to eat 3 or 4 once they get started. Especially if there's a tray of them and you don't have to go through the trouble of ordering them. My brother has the argument that you should eat one potato chip, put the bag up on the top shelf, very far away. So you can have another one; you just have to impose some cost on yourself. Guest: I used to do this with cigarettes when I smoked. I actually kept my pack four blocks away. Russ: There you go. Guest: Shared it with a fellow at the liquor store where I bought the cigarettes. This is in Santa Monica, California. And every time I wanted a smoke I had to walk four blocks to get a cigarette. It worked fine, within reason. Russ: Of course, sometimes you find yourself sprinting. Not walking. But to go back to the twins: are you suggesting--we can think of different hypotheses. One hypothesis is the thin twins just didn't eat a lot of donuts growing up and still don't. Or, they eat a lot of donuts, as much as anybody, but their bodies process donuts differently. Or, they are a type of person that doesn't have a craving for donuts, doesn't get triggered by the first bite as much. And therefore they can't gain weight if they want to. What do you think? Guest: Well, it's interesting. Again, the second and third possibilities are related. So, if that donut affects fat accumulation through the hormones it regulated, then it also will affect craving. So the person that doesn't have a craving could easily be the person--I would argue is the person whose body doesn't want to store calories as fat even when consuming a donut. Russ: Yep. Guest: Now if that person ate a donut every day for the next ten years anyway, that might--I would argue would have an effect on the regulation of fat tissue, so ten years from now they might find they are addicted to donuts and they weigh 20 pounds more. But it happened more subtly. The argument I'm making is that the physiology will tend to drive behavior, so someone whose body is triggered to store fat by these foods is also going to crave those foods. For the twins, they could both have grown up in the same environment. They could both have eaten the donuts. There are variations in this. Like my wife is capable of ordering a dessert at a restaurant, having one bite, and being perfectly content. And if I have one bite of that food, that dessert then takes over my existence. Russ: Me, too. Guest: You know the thing: you are having a dialog in your head about when can I have the other bite, should I have the other bite, should I just eat the whole damn thing and get it over with? Can I get the waitress over here to clear it before things get out of hand? Russ: I know all about that, yeah. Guest: It's somehow related to my body, to the effect that food has on my body. That's the argument. Or anyone's body. So, if you are predisposed to store fat then it's going to happen because the carbs in your diet and particularly the sweets are going to have an effect on insulin signaling and the hormone leptin and other hormones and that's going to start to get your fat tissue growing, and as it does your body is going to respond by wanting more of these particular foods. Simultaneously, somebody might burn off the carbs easily. So, a Lance Armstrong or a Michael Phelps who can eat 15 donuts and might crave those donuts just as much as you do but in that case their body is going to partition that fuel into being oxidized in the muscle cells, and they are going to work out for 3 hours after they eat their donuts; whereas I'm going to just take a nap for 3 hours after eating donuts. There's a lot of variables involved. It's one of the things that makes this so hard to study. Russ: Yes, just like economics. Guest: Yeah. Because you can imagine doing a study where you said let's feed people 3000 calories--this is one of the studies, recently with a colleague, Dr. Peter Attia, we started a not-for-profit called the Nutrition Science Initiative. We have support from a Houston philanthropist to fund research that we think will help clear up these controversies with the help of the obesity researchers. It's all very exciting. It's happening so fast we don't even have a website up yet. But we started talking about what experiments to do and which experiments have been done in the past and try to assess this. So, often people would say: Let's feed obese individuals 1700 calories of diet; one will be low carbohydrates and one will be low fat. But now what they've done is beside from assuming off the get-go that you have to eat less, you have to eat as little as 1700 calories to lose weight, they've removed hunger from the equation by not letting their subjects eat any more than 1700 calories. So now even if one group is much hungrier than the others--the low carb group loses weight effortlessly as does the low fat group but the low fat group is hungry--it doesn't matter because they can't eat more. They are not given any more. So that's really not a valid experiment. But another way to do it, actually the way we want to do it, is to set calories high. So, we believe if you feed them both, say, 3000 calories a day, you'll be able to see the difference between these two paradigms of the way regulation will manifest itself. That's the regime in which you can demonstrate a difference between total calories consumed and the macronutrient content of the diet. But now one of the problems is you are ignoring satiety. So by fixing calories at all high, now you are saying we don't care if you are satiated at 1700 calories. We want you to eat 3000. So that could be problematic. If we allow them to eat as much as they want. This would work for animals, to some extent, but for humans we'll start getting what we call intervention effects: we're using obese subjects who want to lose weight; that's why they entered the study. So they might decide to eat less and be hungry all the time because they want to lose weight. So now we are not going to see the full physiological effect of the diet. These are the kinds of issues we have to work out. And they have to be thought through very carefully because if they are not you could get the wrong answer, even with a study that's otherwise very meticulously planned and carried out.
1:03:59Russ: Yes. It would not be the first time that a meticulously planned and careful study ran afoul of selectivity bias, countervailing things you didn't control for. It's a huge challenge. Of course what you really want to do is put sensors on people from birth, follow them through their life so that you know exactly what they ate rather than relying on a survey after the fact of what they ate 5 years ago, which is unreliable, weigh them every day, and get a massively wonderful data set. As long as you had every human being, you'd be fine. Guest: But even then you'd still only have an observation. Because unless you can not only put sensors on them but put shockers on them so you could stimulate one group every time they go near a donut-- Russ: Correct, you need a control group-- Guest: And the other group gets a very pleasurable sensation every time they go near a rib eye. Russ: Yeah. You hear an aria, when you see the plate of pasta you imagine you are in Italy. It's hard to do. I think one of the themes of both your books which I think is deeply appealing and slightly dangerous but I think for an honest person there is some value there: there is an inevitable tendency to use oneself as a data point. So, if you ask me which is easier--to cut your calorie consumption or cut your carb consumption, I'd say it's carbs. That's much easier to sustain. And so I'm more likely to lose weight and keep it off. That my attempts in the past to reduce intake to moderate my calorie consumption, even if that's a correct theory, have not worked because I can't sustain it. Whereas the carbs has a chance of being sustained. Zero carbs does not--it has a similar problem, I think. Guest: I'm not arguing for zero carbs. Except again, a lot of the arguments kind of get confused along the way. I'm arguing that for some obese individuals, some types of diabetics, 0 carbs may be necessary to restore them to some form of--near 0 carbs, in effect animal products and green leafy vegetables and nothing else--may be necessary to get them to a state of sort of near metabolic health. And that there are gradations of metabolic disturbance, metabolic disease, and the more subtle your disease is, the less carb restriction you need, the more refined grains and sugars you can eat. Although I think everyone would benefit from getting rid of sugars. And then for the 250-, the 300-pounders, the Type 2 diabetics, that's a different problem. Or it's a far greater problem and it requires a far more serious intervention. And this isn't a one-size-fits-all, hey, let's give everybody some whole grains, fruits, and vegetables because we think it's a healthy diet and we don't care if it's only a healthy diet for a subset of the population and for that other subset it may be better than what they've been eating. But it's not good enough, it's not severe enough to redress their health problems. Russ: Yeah. Although I have to say, the economist in me that looks at tradeoffs--I just happened to watch the movie Michael with my children. It's a John Travolta film. There's a really pleasant, delightful scene in there where they order two kinds of pie, of every kind of pie on the menu, and they sit around, and they are really happy. It's a really great scene. Andie MacDowell is not my favorite actress, but she's pretty good in this, sings a song about pie; and there's a great aura of love in the room. And there's a scene later where Michael, who is possibly an angel--we don't know in the movie if he's real or not--but he turns to the dog he's been hanging out with and says: You know, you can never get enough sugar. And it's a metaphor for the sweetness of life. But it is interesting how food is more than just things that make us fat and thin. Guest: No, that's true. But I'm going to give you a counter-metaphor. Russ: Yeah, go ahead. Guest: I used to be a smoker. Smoked first cigarette upon waking up; cigarette after breakfast, cigarette during work, during the morning walk to the gym, after the gym, after meals, between courses, after courses; cigarette after sex, of course. When you are a smoker or this is probably true of any drug, you can't imagine life without it. All pleasures are integrated through this cloud of cigarette smoke and nicotine. I lived in Paris off and on in the mid-1980s, and after I quite smoking I couldn't imagine returning to Paris, my favorite city in the world, because what you do in Paris is smoke and stroll, smoke and shop, smoke and eat, smoke and sit in cafes and smoke. Cigarettes are joy when you are a smoker. Just as food is joy, sugar is joy. And the interesting thing when you try to quit smoking is there's three weeks where you crave it constantly. Then constant cravings fade and then it's kind of longing. You're mildly depressed all the time because cigarettes really did mediate much of the joy you have in life. And then after a year or two that passes and after three or four years you can't imagine ever having smoked. And certainly can't imagine doing it again. And I would argue the same thing happens with the joys of sweets, if you give yourself a chance. The problem is sugar is so much more integrated into our lives and into our foods that it's almost impossible to ever get to that place where it's not consumed. And then fruits have sugars, berries have sugars. So you never get to the state where you are not a sugar eater. Although I know people who have certainly tried, and I would argue maybe a few people succeed. But I am a big believer in the need for joy in life, and what I used to get from the bread pudding at Hal's restaurant on Abbott Kinney in Venice, CA, I can now get from the steak, if I lived in New York, at Peter Lugar's; that I would be able to eat without thinking I was killing myself. Russ: Yeah. There are substitutes. Guest: And there's a lot to be said for eggs and bacon in the morning, if you don't believe you are killing yourself. And if you do, or if you are killing yourself, at least you get a lot of good breakfasts before you go. Russ: Yeah, well, that's the issue. A lot of people, I would just mention, although beer is not on my diet any more, other forms of alcohol are relatively low carb, so there are other kinds of joy, and as you point out a steak, etc. Of course, the complexity here is all these effects are, as you say, mitigated through genetics and life and all kinds of individual differences. Lots of people eat lots of potato chips who live long healthy lives, and lots of people eat lots of steaks and live long, healthy lives. And we just don't know so much about what it will do for us. Guest: Well, that's true. Again, and this is getting back to cigarettes, only 10% of smokers get lung cancer. But we know that cigarettes cause lung cancer--from the people who do get lung cancer, some 80-90% get it because they were smokers. I'm arguing the same thing with obesity. And then the other question to keep in mind, and often you get this thought about these very low carb, high fat diets are too restrictive. Doctors will tell me this: My patients are not going to do this. A counter-argument is: If your patient is a Type 2 diabetic or obese and he or she knew that they could be healthy--not have to take insulin, not have to take their statin, not have to take this drug, the hypertension drug, the blood pressure drugs--and that all it required was making this transition, this dietary transition, akin to a smoker quitting smoking or an alcoholic giving up alcohol, which are not easy things to do. But if their patients knew they could be healthy. And there are clinical trials suggesting that a large proportion of Type 2 diabetics could be drug free if they didn't eat these carbohydrates. How many of them would be willing to make the effort? How many of us would trade off--you and I were talking 20, 30 extra pounds. We're not pre-diabetic; we weren't becoming--I don't think so. There's a lot to be said for being healthy, and I think a lot of us will make the sacrifice if we really had the faith that if by doing so we could and would be healthy. Russ: Well, the other thing I would add, since I've cut out sugar and carbs and starches of that kind, that I have more energy. And it's probably just psychological, but it's working for me, so, hey, that's good enough. Guest: Yeah.
1:13:57Russ: I could be fooling myself, but if it is it's working. We're going long here, but I just want to ask you one more question. You are a journalist who works in science. You are very aware of group think; you are very aware of the problems of confirmation bias. And you've accused others, and I think correctly of making terrible errors in scientific judgment because of their failure to avoid these problems. But now you've become a crusader of sorts, and you've got a new religion. You've rejected the old; you've got a new one. And, as I said earlier, I'd love to think it's the true religion. But you do put yourself at risk of being prone to confirmation bias and making the mistakes that you've accused others of. How do you keep that from happening? Surely others have accused you just as you've accused them of ignoring evidence on the other side. Do you think you are guilty of that sometimes? Guest: Yeah, obviously. And at some level it's a very seditious[?] problem. I mean you look at a paper--two papers come out and one of them supports your point of view and the other one doesn't. So you read the other one very closely to find out why you don't believe it. Russ: Yep. Guest: Might spend an hour doing it. And the one that agrees with you, you go: Oh, this is great. You read the beginning and the discussion and that's the end of it. One of the arguments that I've been making--we all come with bias. None of us is bias-free. I have a bias; as I said, this should be the null hypothesis. And once I phrase it like that it gives me the opportunity to say: I need remarkable evidence to refute it. So, this poorly designed free living study isn't good enough; rat studies--you know, we can demonstrate anything with rats, we've just got to find whatever species of rat we decide. So you can come up with a lot of reasons to ignore evidence that seems contradictory. The nature of science isn't every paper that comes out is right, every result is right, every interpretation is right. There's a huge amount of chaff out there, and we all get to choose what we think is the wheat. Ultimately it's a scientific question. I believe that every book I've written is as much about good science and bad science as it is about the subject. My first book I watched physicists at Cern, the huge European physics lab, discover nonexistent elementary particles. My second book, I documented the scientific fiasco called 'fusion.' And then I moved into public health and ended up writing two books about nutrition. They are all basically the same book. The difference in nutrition was that there was this alternative hypothesis that kept getting passed over, swept under the rug, that seemed it obviously should be the null hypothesis. And I just dragged it out and said: Let's just look at this. And now, one of the arguments I'm making is: Let's do the best science we can. Because in all these fields, one thing I can state definitively about nutrition, chronic disease public health research, is: Because of the problem of doing human experiments--the cost, the complexity, the fact that you've got real, free living human beings involved who can think for themselves, it's excruciatingly hard to do the science that is standard rigorously and meticulously enough to get a reliable answer. So one of the things I've said, we've done, actually co-founded a nonprofit that's going to fund research. And we've put together a consortium of people who we think are the best scientists in obesity and chronic disease research to help design and oversee the experiments. And then--it's funny--I'm the one who is always saying: look, we might find that the conventional wisdom was right all along, at which point I better find a shoe store that's willing to hire me as a salesman, because that's what I did in high school and I might still be able to do it. But ultimately it comes down to: you get a hypothesis; people either decide the hypothesis is viable or not. In this case you can test it on yourself, on an n of 1, which gives you an advantage over most other hypotheses. But ultimately I've been arguing: Let's just do good science. Let's just do the kinds of studies--people think these answers were settled in the 1960s. And they weren't. Not even close. So let's do what should have been done in the 1960s. And hopefully--we have some philanthropic benefactors behind us; we hope to get more and it looks like we're going to be able to raise enough money to actually answer these questions definitively. But ultimately that's what we need--just really meticulous, rigorous science. And it can be done. And I think it will be done.

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COMMENTS (78 to date)
Floccina writes:

A few weeks ago, I heard on the radio a discussion featuring the authors of the book Zoobiquity. They made a strong case that it is simply abundance that is allowing us to get obese. They pointed out that our pets have gotten fat along with us and that animals in the wild get fat in times of abundance.

Perhaps Gary Taubes would like to take a look at the book Zoobiquity. They also have a web page.

Mads Lindstrøm writes:

Just a detail, but by saying "we fought a war against them" and then naming Bohr, it is implied that Niels Bohr was a German researcher. He was Danish.

grover writes:

Reading Taubes for the first time is very exciting. There are few things more electrifying than discovering that everyone else is delusional and that you - you - are one of the elect few who see past the nonsense.

Taubes is obviously correct that fat is regulated. Animals in the wild effortlessly maintain their weights, and native populations rarely suffer from obesity and diabetes. Why would evolution, a master architect of homeostatic mechanisms, leave something so important as body fat percentage totally unregulated? Taubes is doing a service by fighting the idiotic idea that, for instance, adding a daily square of chocolate to one's diet can make one gain 15 pounds in a year. The other day I was horrified to read something to this effect on the Mayo Clinic's website.

However, Taubes's model of weight regulation in which insulin "locks up" fat is not so obviously true. I urge listeners to consider this piece from Stephen Guyenet, who says that smart obesity researchers have considered the insulin hypothesis, and rejected it. Fat regulation is more complicated, he argues:

http://wholehealthsource.blogspot.com/2011/08/carbohydrate-hypothesis-of-obesity.html

I need to dig into Taubes's long responses to Guyenet. I tried before, but was discouraged by the philosophy of science-related logorrhea and Taubes's attempt to peg him as one of the "gluttony and sloth" crowd. He didn't seem to have any pointed counterarguments.

(Perhaps I wasn't being fair to Taubes and should have read on. I don't know much about this topic and must pick experts to trust.)

emerich writes:

I've read Taubes' book and have to admit it's persuasive. But Russ has also taught me to stay skeptical no matter what. I agree with the previous post that Stephen Guyenet is worth a hearing. He thinks that "palatability" is a major culprit. Those irresistible potato chips are high in both fat and carbs, and also have great flavor. Guyenet cites a study that says rats and mice get fat real fast on human junk food, which is designed for maximum palatability.

Ak Mike writes:

Russ, I yield to no one in my admiration for you and the Econtalk podcast, to which I am a faithful listener. But your nutrition programs are a disturbing contrast to your economic podcasts. For the latter, you invariably have highly qualified, usually Ph.D. economists, typically with outstanding professional credentials.

Yet, with nutrition, your guests have been entirely devoid of formal training in a scientific field with hundreds or thousands of highly trained researchers with positions in academe, government, and industry.

You know perfectly well that intense controversy is common in academic disciplines. If every biochemist and qualified metabolic researcher rejects Taubes' theories (as he suggests), that implies to me that he is a crackpot, not that he possesses a truth that all the scientists reject because of prejudice.

Please get a qualified scientist on your podcast to comment on Taubes' theories.

Doug Tree writes:

Prof. Roberts,

As a chemical engineer (just to bring my background/bias out front), I find Mr. Taubes dismissal of the first law (of thermodynamics) concerning and I think he often confuses the issue with his desire to be rid of the conventional interpretation.

To make a more concrete analogy, consider a bathtub with the faucet on and an unplugged drain, an analogy for the open system that is our body. In this analogy, the faucet represents our food intake and the drain our consumption and expulsion of energy. The water level in the tub is our fat level. Clearly the amount of water in the tub is not necessarily related to. The influx and outflux of water in the faucet and drain.

He wants to make the case that 1) the rate of intake and outflow are regulated by natural mechanism and 2) that these rates are influenced by the type of food that we eat. If we take these to be true -- and it would appear there is evidence supporting this -- that still does not change the validity of the energy balance. Rather, it simply turns the discussion towards the mechanisms of regulation.

I think that claiming the "energy in/energy out" paradigm is wrong clouds the issue. It is really a debate of regulatory mechanism.

Doug

Rufus writes:

I have not listened to this episode yet, but plan to do so on the morning commute tomorrow. I have, however, read almost everything that Taubes has written on this topic. What I like about Taubes is that he is very clear on what is a hypothesis vs. what other scientists call a "fact". In other words, if you read Good Calories, Bad Calories, you'll see that many of the studies have been poorly designed or else observational studies that cannot prove causality. In addition, Taubes' work goes a long way to showing the political and media influence over what we believe.

Taubes has done extensive research on this topic, including 5 years worth when writing GCBC. That can hardly be dismissed. However, the science is not settled. Stephan Guyenet presents some very interesting research on the role of Leptin, food reward, palatability, and other factors that also play a role. Taubes targets Insulin, Guyenet targets Leptin. Time will tell as more research is done.

For a very interesting podcast with Guyenet, I recommend listening to this interview with Chris Kresser. In this podcast he explains in more detail his "set point" theory and how the body has mechanisms to defend a whatever level of fat that it "thinks" is optimum. For example, the body can lower metabolism, make muscle contractions more efficient, or change the balance of use of carbs vs. fat. All of that is why the thermodynamic model "calories in, calories out" is a bad model. (on that point Taubes and Guyenet certainly agree).

http://chriskresser.com/podcast-episode-i-interview-with-stephan-guyenet-on-obesity-and-weight-loss

(there are several other podcasts on that site that continue the discussion with Guyenet and address causes of obesity). If I'm not listening to an Econtalk, then I'm likely listening to an episode of Chris Kresser. Highly recommended.

David writes:

Having Taubes on the first time was interesting. He holds a (very) minority opinion on health, weight, and nutrition, and it's often fun to listen to those on the outside of science. I don't know what is gained by having him on less than a year later. I was disappointed, just in terms of opportunity costs: having him take up one of the precious 52 yearly slots on EconTalk means that I'm missing out on overhearing a potentially great conversation you could have with someone else.

SR writes:

I second "Ak Mike's" recommendation...why not interview a real authority on the issue?!?!

Marion Nestle would provide some excellent counterpoints to Taube's hypothesis and she would also offer interesting insights regarding the politics and economics of food and nutrition.

Like the first time Taube's was interviewed, I was surprised that Russ didn't challenge Taube's fuzzy thinking, logical fallacies, pseudo-scientific rambling, and blatant cherry-picking.

Ken writes:

Thanks for the link to Stephen Guyenet's prespective, grover. I will dig into it sometime. I have a lot of interest in neuroscience, so it will be interesting to get that perspective. He uses lots of references, but there's a lot of dogmatic scientists in the nutrition field.

Personally, I don't find the 'law of thermodynamics' perspective to be persuasive. It assumes the human body to be a closed system and that calories do not escape unabsorbed.

I first tried the low-carb diet in 1995. I was a major skeptic and tried to prove it wrong by tripling my caloric intake, while keeping carbs below 20g per day. I lost 20 lbs in 2 weeks and another 20 over the next month or two. I gave it a major challenge by filling my freezer with microwaveable bacon and eating more than a pound of bacon per day as additional snacks. I was eating heavy cream out of the container just to add additional caloric intake.

I don't recommend that approach, but oddly my cholesterol came out better than it had ever been. I always had extremely high cholesterol. I have always had good cholesterol readings since I began watching my carb intake.

I don't know if the insulin story is correct, although it seems intuitive to me that insulin resistance could develop from long term elevated insulin levels. I do know that in my case total calories make little or no difference.

Dan Lundmark writes:

I've not read Taubes book, however after listening to this podcast I want to share my view that the human body is much more adaptable than presented, where people can consume primarily "high-fat" raw carbs and with no problems, just as gorillas can eat primarily greens & fruit...

A real world example is the fitness community of athletes and marathon runners who are fruitarian and live "high carb raw vegan lifestyle" (see http://www.30bananasaday.com or TV interview here http://youtu.be/s250objJpWg ).

It would have been great to hear him address the success of this approach. Perhaps the key is the type of carbs consumed.

Michal Ty writes:

There are two ways to loose weight: regulate intake, so that you ingest less calories than you use, and de-regulate processing, so that you don't eat carbs which forces the organism into "starvation mode" which burns off your fat reserves without making use of the fat you intake.

I think we've evolved on vegetable (i.e. carb/protein) diets and the mechanisms that regulate the use of our fat storage are based on carbs -- there are virtually no protein-only foods, whereas fruit is almost all carbs, so it makes sense to focus on lack of carbs as an indicator of starvation.

Fat in our fat tissue isn't made from good wishes and fairy dust, it's made out of energy -- it's a type of a battery. To say that you can maintain a low-calorie diet, use a lot of energy (i.e. more than you eat) and still get fat is ridiculous. The tribes he describes as having low calorie diets and still being fat must have had either misled the researchers as to how much they eat, or had other types of medical problems, i.e. they retained water, or had some kind of skin disease that makes skin flaps etc. They certainly didn't get fat while eating less calories than they used.

Considering that he mentioned them getting fat when processed grains became available, I imagine that was the point when food became very abundant to the indigenous population, especially if they had valuable items to trade. When getting food is a dangerous struggle -- hunting powerful beasts, gathering in dangerous forests, farming without the help of animals and modern equipment -- people generally eat less, than when getting food is a very easy and pleasant experience, like shopping.

In summary, I think that either you shouldn't interview people claiming to be specialists in the fields you have no expertise in (i.e. biochemistry), or you should invite guests who are considered to be at the top of their field. But I'd rather if you stuck to economy.

NickH writes:

Criticizing Gary Taubes as a non-scientist seems to be an ad hominem attack. Whether he is "trained" as a nutritionist or an epidemiologist is beside the point. GCBC posits a hypothesis that contradicts the mainstream calories-in-calories-out (regardless of quality) paradigm.

And it does so by relying on already-existing studies conducted by "real scientists." The onus should be on mainstream scientists (who get funding to conduct studies) to construct and carry out a study that falsifies the pre-existing paradigm, which is that carbohydrates are fattening.

I didn't find Taubes to be "pseudo-scientific" when he retells anecdotal evidence. He was simply explaining the ramifications of the carbohydrate hypothesis as they play out in real life.

Taubes does not disregard the first law of thermodynamics. I think he came off that way on this interview because the majority paradigm only looks at conservation of energy, as if humans were internal combustion engines. As he noted in the interview, when people get fat they do store more calories than they burn--that's why they get fat. A good example is his discussion of the rats with ovaries removed.

Doug Tree writes:

NickH,

Two comments:

First, I agree with you (at least in part) regarding the "not-scientist" attack. In science we should be rigorously opposed to dogmatism and welcome outside feedback such as those from journalists. However, that being said, by strongly advocating a certain position (i.e. low-carb, Keynesian/Austrian economics, whatever) one runs the risk of losing some measure of objectivity (admitting of course that objectivity is more of a moral virtue than an attainable reality).

Secondly, hopefully to clarify what I mean regarding the first law. My concern is that when Taubes makes a statement such as (paraphrasing) 'the energy in/energy out hypothesis is wrong.' He obfuscates two ideas: (1) the idea of a regulatory mechanism tied to solely to individual will-power (gluttony/sloth argument), and (2) the existence of the conservation of energy applied to a human body. I believe that you are correct that he does not mean to disregard (2) -- I certainly hope not anyway, because he would be seriously in error. But simply that the phrasing of the hypothesis is unfortunate because it leads to confusion.

For instance, Ken seems (if I read his comment correctly) to assert that (2) doesn't apply, when it most certainly does. However, the idea of a closed/open system is a little more nuanced than referenced and the human body is most certainly not a closed system. (My working definition of a closed system is one where mass does not cross the control volume boundary).

Greg Linster writes:

Russ,

Thanks for bringing Gary Taubes back on -- I really enjoyed the conversation. I couldn't help but laugh when you guys were talking about the internal dialogue one has in one's mind when a dessert is sitting on the table. I agree with both of you that having one bite of a dessert is harder to do than is to avoid it all together.

Like you, the contrarian in me is very sympathetic to the argument that Taubes is making, but I fear I'm being blinded by confirmation bias. Part of me has hard time buying the idea that carbs can be this evil. I have been experimenting with Paleo-ish/Primal diets for many years now, but I don't feel all that great when I go very low carb on them. A few years back I implemented intermittent fasting into my lifestyle and saw great results (in terms of leanness), even when I was consuming more carbs.

Anyway, I'm curious: have you tried intermittent fasting? I haven't really heard Taubes mention much about it, but I wonder if prolonged periods with absolutely no food in the system could help properly regulate the hormones and still allow one to moderately eat carbs. I am only one data point, but it seems to be working for me and I think it's more sustainable for most people than a pure Paleo/Primal/Low-Carb diet.

Dan writes:

I was initially disappointed to see Taubes invited back on the program so soon after he covered substantially the same topic in an earlier interview, but I was pleasantly surprised at both the high level of new discussion content and the scientific sophistication of his arguments.

My gut impression is that there is "some truth" to Taubes's nutritional arguments, but there is more to the story. Having said that, he certainly raises some good questions and gets you questioning certain assumptions.

Jen writes:

I have no problem at all with having someone from outside the academic canon talking on a topic - as long as they have something interesting to say (which Taubes' definitely did). There are many examples of where someone not trained in a discipline has come up with a breakthrough idea or concept.

I wonder how Taubes would explain the fact that vegetarians are (on average) leaner and live longer than meat eaters. Of course there might be other factors that come into this (vegetarians may be more health conscious overall) but if Taubes is right then even health conscious people who don't eat enough protein can get fat. As a vegetarian (all my adult life), I eat a diet very carbohydrate-heavy yet I have always been on the slim side. Perhaps it's just genetic (my dad is tall and skinny) and my body is geared to need the carbs to keep at a healthy weight. Does this mean some people eating a protein-heavy diet could become unhealthily thin?

Rufus writes:

If this podcast has peaked your interest and you suspect Taubes of selection bias or simply want to learn more about his theory, I recommend this approach:

Start by reading

What If Its All Been A Big Fat Lie? and

Do We Really Know What Makes Us Healthy?

Both are available for free on his web site.

If the first two articles intrigue you, and you're a data geek, then Good Calories, Bad Calories is a must read. (Why We Get Fat is a more "accessible" book) Beyond laying out the case for the carb / insulin hypothesis, it is almost a detective novel pointing out how political influence often trumped science again and again. That should come as no surprise to anyone.

There are many parallels between his work and the books and commentary by other Econtalk guests like Matt Ridley, Art De Vany, Nasim Taleb, and Richard Epstein (in particular his critique of the FDA). The common thread for me is that centralized planning systems often fail to function as intended - this question of a healthy diet is simply a case of applied economics.

As Taubes points out, population after population has become obese after being subjected to the Western diet. [I'm a Paleo diet person so I say "subjected" rather that something benign like "introduced"] Africans, Samoans, Pima Indians, and on and on are all suffering the health consequences. So, while the best intentions may have been to prevent starvation, the net result is unprecedented obesity, diabetes, heart disease and other ailments. Unfortunately, when the system of government policy, subsidies, and political influence become entrenched - such as the Food Pyramid or the Heart Healthy Diet - it is very difficult to dislodge these ideas - even if they might be killing us.

If you still have an interest after GCBC, and you're looking for someone with the "right" credentials, I recommend reading Paul Jaminet's The Perfect Health Diet - complete with about 600 endnotes. His book will provide plenty of science that support Taubes' theory along with some other interesting developments in understanding a truly healthy diet.

Ken writes:

Michal Ty says "I think we've evolved on vegetable (i.e. carb/protein) diets and the mechanisms that regulate the use of our fat storage are based on carbs --"

You might be right, but this is one of those hotly contested debates (was the evolutionary mix more vegetarian or carnivore). My own guess is that we evolved as both. With one or the other dominating within tribes, between tribes and probably entire societies. As gatherers, there may be advantage to being big and threatening. As hunters, there may be advantage to being lean and fast. Carbohydrate intake could serve as one type of signal as to which body type should preferentially emerge from your eating/activity habits.

My hunch would be that vegetables during evolution were in a carbohydrate-protein ratio more like broccoli or green beans than potatoes or bread.

Bacteria often turn on entirely different sets of genes depending on what nutrient sources are available in the environment. This can result in different morphologies and growth strategies. If humans develop different 'morphologies' based on source rather than quantity of fuel that would not be some new evolutionary trick.

Doug, my point is that 'thermodynamic law' does not apply because the body is not a closed system. Fatty acids are not easily digested or absorbed and often pass through the body. Also the rate of absorption could be influenced by some mechanism. I agree that if one rejects the "energy-in/energy-out" hypothesis, one should explain WHY.

Ketosis alone tells me that something different happens on low-carb. If I cut down to

I guess I'm less open-minded to the idea that it's 'the calories' or that 'nothing special happens' when I reduce my carbs.

John the slender one writes:

As a formerly fat person who has been slender and fit for years I can provide the one-word solution to the obesity conundrum: Willpower.

You control what goes into your mouth. If you eat plenty of vegetables, fruits, whole grains, and legumes you will be fabulously slim and also have a pleasant feeling, throughout the day, of being well fed and light on your feet.

Jason writes:

@grover. Your link to Guyenet is an interesting one. I looked for Taubes rebuttal, but he seems not to have completely published it.

You can read his Part 1 where he argues that 99+% of outsider opinions on an area of science are wrong, but in this case he is in the outsider minority that knows better than the insiders. The tone of the article made me doubt is credentials more. Part 2 argues why Guyenet results might not be relevant to the real world. However, the main part of Guyenet's argument is around leptin and Taubes doesn't give a thorough enough counterpoint on this.

The only conclusion I can really draw, is the unsatisfying one, that it is all more complicated than anyone fully understands at this point.

iBurger writes:

I am surprised by the amount of negative reviews on this page. The low-carb hypothesis is nothing new to us. I have been reading about for ages, ever since the Atkins diet became popular.

This is my theory:

1. Naturally thin people in their mid-20s are still responding to insulin. Given an additional 20 years, they will become insulin resistant and get fat. That is, if they do *not* smoke, are not active, and eat the typical hamburger diet.
2. Genetics matter. If you are short and female, you are in big trouble. It's the tall male body that burns calories.
3. Activity. The American lifestyle is just not good for staying thin. My friend moved to the US and gained about 20 pounds in 6 months. The average American meal has too many calories.
4. Extreme measures: Smoking helps. Drugs help. Not eating breakfast helps. Fasting helps a great deal.

Many of my fellow students in Europe are heavy drinkers and smokers. In general we skip breakfast and do not eat regularly. In my opinion this is helpful to get the fat off. Smoking raises your heart rate because you need to work harder to get the oxygen in the blood. Skipping breakfast helps because you extend your fasting period.

Rod writes:

Taubes spends much more time discussing the thermodynamics angle in his @Google talk starting at 36:00 mark. Watch it.

I loved the topic. I don't need my EconTalk to be econ-related, just thought-provoking. Thanks, Russ.

Oh, and John, as a formerly fat person myself, I ate TONS of veggies, fruits, whole grains, and legumes for many years and it did nothing for me. Nothing! But only when I dropped the grains and legumes and replaced them with fat and protein, my energy level shot way up and I started losing weight. So it's not just willpower for everyone. It is more complicated than that. Maybe Primal/Paleo works for some people, maybe vegetarian works for others, maybe an all-bananas diet works too. Who cares? We can all choose to do our own thing. Taubes is at least starting the conversation, and I thank him for that.

James writes:

Russ, I find it hard to take "science journalists" very seriously. These people build their careers off selling books, not doing science. Sensation sells.

There is a lot of evidence for what Taubes is claiming, and I appreciate his arguments. But I don't like some of his extreme-sounding claims. Carbohydrates do not "cause" obesity in any mechanistic sense. A single example of a person who takes in 3K calories of carbs while sitting at the computer all day and remaining skinny is all you need to refute this claim. Yes I know he talks about genetic predispositions, but the point is he does not speak carefully, he contradicts himself left and right.

This is the problem with having non-academics on the show. Academics are not perfect sure, but they are much more careful than journalists when it comes to making grand claims.

Allan writes:

Doug Tree:

The bounding boxers drive me nuts, which is what makes this particular debate so important to economics.

Let's suppose you have a elderly lady down the street with a little bit of problem with cat accumulation. Clearly, the amount of cat food entering her house exceeds the kitty litter leaving (wherever you wish to draw the thermodynamic border crossing) or she wouldn't be stricken with 400 lbs of living cat flesh. Yes, and if the sun stopped shining, our obesity problem would also go away.

The point about the energy expenditure balance is that this has been widely understood for a long time ("eat less" is hardly a new invention) and the population is still getting fatter than ever despite a massive expressed preference (and near-universal cultural zeitgeist) when you ask people about not being perceived as panting, tottering pie wagons.

Why is this? Perhaps because food and diet mobilizes our metabolic response to every other stress in life, for better or worse? Perhaps the cat problem could best be understood in a framework of socialization and isolation? But heaven forbid that this becomes central to our conception if we already know that constricting the input of cat food is a sufficient measure.

Wiki blurb: "Taubes studied applied physics at Harvard University and aerospace engineering at Stanford University." As the players used to say to the new arrival about Gretzky picking up his open teammate trailing the play, "No need to shout. He knows. It only helps to wake up the dim bulbs who aren't already paying attention." Do you show up at town council, and frame the issue of the woman with all the cats by first clearing your throat and mentioning the 2nd law? I'm so far past seeing the point here.

This is central to the whole sphere of economic debate. You get a bunch of camps, each with a fetish for a different simplifying narrative involving a bounding box which would clearly have already delivered an answer if that was all the clarity required. This often degenerates into a loudness war, with the supposition on every side that if only everyone would believe in the right-thinking bounding box simultaneously, then clarity would finally reign supreme and perform its magic abatement. Personally, when I left high school I voted the supposition of simultaneous enlightenment most likely to grow old with 200 cats. It didn't seem to describe the adult world I was entering one hoot.

Mark Sundstrom writes:

Like iBurger and Rufus (and others), I am surprised at some of the negative comments posted here. Russ, you can invite Mr. Taubes back anytime as far as I'm concerned.

Those who think he is not qualified to write about these topics have not researched his qualifications and past publications.

There is new research to be done and I look forward to hearing about the initiatives that he and others are pushing for.

I've told several friends about this stuff and they have all been impressed by the results they've personally seen so far. (Of course, that's anecdotal data and proves nothing.)

Even if you are a skeptic about this, I doubt you would disagree about the problems with sugar intake. Try cutting out just sugar and see how things go.

Thanks, Russ, for my favorite series of podcasts.

Mark Sundstrom

Tuure Laurinolli writes:

After having listened to half of the podcast, I find the presentation of the thermodynamic aspect confusing. Surely Mr. Taubes does not claim that humans are able to eat less than they consume and stay both fat and alive for extended periods of time?

Now, when one eats more than one consumes, it is certainly plausible that one does not necessarily get fat. All this requires is that the body is not one hundred percent efficient at converting the food into something the body can use or store.

Steve writes:

I've been listening to Russ for a long time and I'm a big fan; however, this is my first visit to the Econtalk website. Wow, I'm very impressed with the quality of the comments. It seems that intelligent, thoughtful programs attract intelligent, thoughtful listeners. Who woulda thunk it? :-)

Everything that I came here to say, regarding Taubes, has already been said. I'll add a couple of points. First, in the discussion, Russ reminded himself and his audience that he must be careful about confirmation bias, and then he proceeded to fall victim to that trap. Russ simply did not ask the kinds of critical questions that needed to be asked. I suppose I can chalk that up to Russ having an economics background rather than a scientific/nutritional background. It just goes to show what Russ also said about confirmation bias is true: Just because one is aware of the possibility of confirmation bias doesn't mean one won't fall prey to it.

Second, Russ made what sounded to me like an amazingly self-defeating statement: He said that he WANTED Taubes' theories to be true. Why is it desirable to deny oneself the undeniable pleasure and variety of carbohydrates, even unrefined carbohydrates, in order to be healthy? I don't know about Russ, but this sounds like a recipe for a pretty boring diet. I might do it if I had to, but I certainly wouldn't "want" it!

And finally, I have to wonder how people eating a more "balanced" diet - one that eliminates refined carbs but includes unrefined carbs - compare to Taubes' diet which virtually eliminates carbs. If we're going to compare diets, I prefer not to compare it to a diet of fast foods, pastries, sodas, potato chips, and beer. :-)

Richie writes:

I don't much like eating meat, so any news/science supporting the low-carb diet is discouraging to me. I've spend most of my adult life needing to lose 25-50 pounds. I've had short periods of success, but nothing lasts too well for me.

I just don't know how I could possible make the low-carb diet work for me.

Doug Tree writes:

Allan,

To clarify, my point was that Taubes left the thermo confusing and he was really debating about mechanism. In your metaphor, he made it sound (at times) like cats can enter the house and they'll just disappear. Other times he stated the principle correctly. I'm glad he has an engineering degree (so do I), but I don't think an appeal to authority is a carte blanche either. In economics appeals to authority are certainly part of the problem (95% of economists agree!).

That being said, Taubes has a flair for rebutting the status quo. This is a double edged-sword. At the same time he is condemning current obesity research (perhaps rightfully), he is saying things like "energy-in/energy-out" is wrong. This can easily create confusion in someone not fluent in basic (or not so basic) science (see several comments on this page). So, I'd like to say that you can debate about what the real problem is (will-power, refined grains, cats), but try not to confuse people about thermodyanmics along the way. Too many people (dim bulbs?) already think that they can power their cars with water and that electric cars have no pollution.

In addition, I don't think I ever meant to draw a neat little box around the problem and say that the whole answer was 1st law this or 2nd law that. Given that, everyone has a background and frames the problem in a way they can understand. I hear the talk and think of feedback loops, PID controllers, and CSTR reactors. It's what I know. I also like to make mathematical models. We learn by metaphors and models (see also: why its hard to understand quantum mechanics). As a practitioner of science, I also tend to think that different backgrounds are more helpful then hurtful. The problem is when (1) backgrounds devolve into philosophies that cannot be reconciled because (2) there are no testable hypothesis.

Your last point is a more interesting one. To make a metaphor (if I may) you seem to say that "bounding boxers" (presumably me) are all given piece of the picture and simply try to interpret the whole picture in terms of their piece. Basically a confirmation bias/limited knowledge hypothesis. The problem is Hayekian: is it really possible for us to know anything without reducing it to something we have experience with? What is knowable? Is the whole process too complex to be conceived by any model? Perhaps. Perhaps it's the human condition to have a finite understanding (and why we should all be a little more humble about what we 'know'). However, we've been successful in the past in understanding some things that have emergent order (statistical mechanics, self-assembly). At the end of a 2010 podcast Robert Laughlin suggested (related to the idea of universality in Field Theory) that maybe all of our physical laws are emergent and we just haven't seen the complexity beneath them (paraphrase).

In the end, I don't think that metabolism is quite *that* complicated however. Taubes doesn't either. He has a testable hypothesis that he intends to test (objectively?). But then again, I'm only human.

Doug

Allan writes:

Ak Mike, James:

Academics are not perfect sure, but they are much more careful than journalists when it comes to making grand claims.
Would it were so!

The white coats follow the paradigm of Bruce Bueno de Mesquita like everyone else (Mesquita's interview is one of seventeen in the Econtalk Favorite Podcasts archive). If their specialization is narrow enough, it's a darn small selectorate they keep firmly fixed in their vigilant side-view mirror.

You should spend some quality time with Peter Woit on Not Even Wrong. Woit is a professional mathematician, which in the minds of the people he criticizes casts doubt upon his legitimacy, people who style themselves as physicists, but have in fact been doing 99% mathematics and 1% physics since string theory became the latest and greatest hot fad in the early 1980s. But still--in their minds--Woit is unqualified to carp. Why has the supreme selectorate of sub-atomic physics formed this strange cartel surrounding a branch of mathematical speculation completely divorced from experimental verification? For economic reasons. The particle accelerator they would like to have would be about the radius of the solar system. They suspect this won't be funded any time soon, so they've found a way to content themselves with the E$3 billion Swiss-French benchtop toy, which is now going great guns to complete the verification of physics as unveiled in the great flowering of the 1960s.

Everyone looks over their shoulder at the power group that controls their rice bowl. What makes you think scientists do more or less of this than anyone else? Journalists have a much larger selectorate than particle physicists. Taubes has positioned himself as a lightening rod in one of the most contentious debates going. You don't think he's watching his back? Why are Taubes' book revenues so much more explanatory of his scruples than what a hadron physicist is likely to say in front of a congressional committee to secure another year of beam time? Do you think "We're discovering the God particle!" has no overtones of populist exploitation?

Academics are not perfect sure, but they are much more careful than journalists when it comes to making grand claims.
Pardon me as I stumble back onto my chair. It's not gaining persuasion in the repetition.

My starting point for the inherent credibility of scientists (which is different, by far, from the scientific enterprise as a whole) was the tobacco wars of the 1970s. There was no shortage of white coats in parade to contest the primary hazards of smoking, though this was by then clearly a losing cause to any thinking person. A lot of scientists were approached with a Big Tobacco business card reading "we have ways to butter your bread". Now it turns out the primary hazard was pretty irrelevant: the addicts themselves were being controlled by chemical tweaks to the nicotine delivery system, as we found out later. The real purpose of this kayfabe circus was to taint the well on the public discourse over the effects of second hand smoke, and the frightening prospect of Libertarian attrition, who while defending your right to kill yourself tend not to defend your right to spill smoke into my environment and kill me. Nothing spells demise like the prospect of the Libertarians and the Nanny State in unholy collusion, each to their own cause. The decline in public acceptability of smoking has in fact severely dented the uptake of the Big Tobacco lifetime annuity program (the word "annuity" has actually been used inside the tobacco and alcohol delivery industries in reference to what's at stake in winning the teenage consumer).

I have a lot of respect for science, as a human tradition, but no presumed reverence for any particular scientist. I hold scientists and journalists to the same standards of skepticism: they need to make a sensible argument not entirely devolving to the approval of their own kind.

I mentioned Big Tobacco because it has lessons to teach us about Big Skinny: a $10 billion dollar industry now demonstrating far more success in buttering bread than withholding it. There's no guarantee Taubes is on the right side of the science, but I welcome his frigid gust of derision into the comfortable room of their tiny selectorate.

Rufus writes:

@Allan - great post. I love finding links to science sites like Not Even Wrong even if some of the discussion exceeds my recollection of the math courses I took over 20 years ago.

I'll offer up one more post, just to try to show the economic implications of Taubes' work. Basically, he's saying carbs are the root cause of obesity, and one of the key carbs in our diet is wheat. There are many critics of wheat, and studies that show that it has a toxic effect - and more than just on those unfortunate people who have Celiac disease.

Lately, Bill O'Reilly has been off wheat, losing weight, and proclaiming the health benefits. Study of N=1, but still...

http://www.ksn.com/news/local/story/Bill-OReilly-credits-no-wheat-diet-to-his-weight/X7F8CoS2Pk-yTJEM7ZTTyw.cspx

What is interesting about that story from an economic perspective is the statement of the farmer: "There would be a lot of farmers out of business, if that happened."

Then, of course, and "expert" in the article says "There is no scientific evidence to back up that gluten is toxic to anyone who does not have celiac disease, which only affects about 1 percent of the population"

Well, actually, there are studies like this paper in PubMed that shows that there are "... at least 50 different toxic epitopes in gluten peptides that have been shown to destroy cells, dysregulate the immune system and cause leaky gut."

http://www.ncbi.nlm.nih.gov/pubmed/22109896

and this post by Chris Kresser that discusses research that shows as many as 12.5% of the population has celiac disease along with other suffering from the 50 other toxic components of wheat.

http://chriskresser.com/beyond-paleo-2

So, where are we? Sounds a lot like the smoking situation that Allan just referenced. We have a potentially toxic substance (wheat) and we have scientists lined up on both sides with opposing views. If Taubes is right, we should quit eating wheat because it is making us obese. If other scientists are right, we should stop eating it because it is causing autoimmune diseases. If the other scientists are right, then farmers in Kansas keep their jobs, General Mills keeps making cereal, and people get to eat low cost food.

People on the street might wonder "If we can't eat bread, what would we eat?" "How could we afford to eat if we didn't have cheap grains?" and other similar questions. At the same time, if the market is allowed to solve this problem, no one will starve. There may be a redistribution of how our income is spent, and bakeries across the nation would close and re-open as grass-fed beef jerky or smoked salmon shops. Who knows. I'm almost excited to see this play out. I just have the ethical dilemma of not wanting increased demand to push up the price of what I eat while simultaneously thinking I should tell people not to eat wheat because it is toxic and causes obesity.

John Danforth writes:

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Andrew writes:

I am relatively new to Econtalk and have been very impressed with the quality of the podcasts... until this one. All of what I wanted to say has been said in this thread, but I feel the need to add my voice to the critics.

Taubes ideas may have some value, but I cannot tell from the podcast. Russ, who normally is the king of asking the awkward question, lets multiple vague and sometime contradictory answers go by without challenge. Steve's post above say's it all really. Russ say's himself that often being aware that one has a confirmation bias is not enough to avoid its effects, this podcast is a case in point.

I apologize if this post comes across as a criticism of Russ, it is not meant that way. He is an amazing interviewer/podcaster, with a sharp intelligence that he can apply to many wide ranging fields, I am in awe of his abilities.

Just one point to the topic itself (I have not read the book), in the podcast Taube gave examples of groups that had high carb diets, but were otherwise healthy, and still suffered from obesity. IIRC all these groups were in North America, and relatively small. How can these examples be considered significant, when it is so easy to find a counter example e.g. Vietnam - nearly 100 million people, a very, very high carb diet (all meals with noodles or rice , and sometimes bread!) and very low incidence of obesity in the population.

Again I am not saying Taube is wrong, but I do think many of his statements in the podcast needed to be challenged.

Doug writes:

Allan,

To clarify, my point was that Taubes left the thermo confusing and he was really debating about mechanism. In your metaphor, he made it sound (at times) like cats can enter the house and they'll just disappear. Other times he stated the principle correctly. I'm glad he has an engineering degree (so do I), but I don't think an appeal to authority is a carte blanche either. In economics appeals to authority are certainly part of the problem (95% of economists agree!).

That being said, Taubes has a flair for rebutting the status quo. This is a double edged-sword. At the same time he is condemning current obesity research (perhaps rightfully), he is saying things like "energy-in/energy-out" is wrong. This can easily create confusion in someone not fluent in basic (or not so basic) science (see several comments on this page). So, I'd like to say that you can debate about what the real problem is (will-power, refined grains, cats), but try not to confuse people about thermodyanmics along the way. Too many people (dim bulbs?) already think that they can power their cars with water and that electric cars have no pollution.

In addition, I don't think I ever meant to draw a neat little box around the problem and say that the whole answer was 1st law this or 2nd law that. Given that, everyone has a background and frames the problem in a way they can understand. I hear the talk and think of feedback loops, PID controllers, and CSTR reactors. It's what I know. I also like to make mathematical models. We learn by metaphors and models (see also: why its hard to understand quantum mechanics). As a practitioner of science, I also tend to think that different backgrounds are more helpful then hurtful. The problem is when (1) backgrounds devolve into philosophies that cannot be reconciled because (2) there are no testable hypotheses.

Your last point is a more interesting one. To make a metaphor (if I may) you seem to say that "bounding boxers" (presumably me) are all given piece of the picture and simply try to interpret the whole picture in terms of their piece. Basically a confirmation bias/limited knowledge hypothesis. The problem is Hayekian: is it really possible for us to know anything without reducing it to something we have experience with? What is knowable? Is the whole process too complex to be conceived by any model? Perhaps. Perhaps it's the human condition to have a finite understanding (and why we should all be a little more humble about what we 'know'). However, we've been successful in the past in understanding some things that have emergent order (statistical mechanics, self-assembly). At the end of a 2010 podcast Robert Laughlin suggested (related to the idea of universality in Field Theory) that maybe all of our physical laws are emergent and we just haven't seen the complexity beneath them (paraphrase).

In the end, I don't think that metabolism is quite *that* complicated however. Taubes doesn't either. He has a testable hypothesis that he intends to test (objectively?). But then again, I'm only human.

Doug

Tim Wright writes:

I did enjoy the podcast and do think that Gary Taubes has important things to say. I have read his books and familiar with his work so I can't comment whether the podcast was confusing or not. I have heard him give a better description why the calories in/calories out system is the wrong way to think about it.

I do think we should give everyone his due and not be concerned about his credentials. People with credentials like nutritionists have been trained with a specific world view. They should not be given deference just because of their degree.

About pets, we are feeding our cats and dog food that is more meat and less grains, trying for lower carbs. I have not looked into it but I wonder if many of the common pet foods contain a lot of carbs because it is cheap. So our pets get fat. Our cats are not fat, yet anyway.

Tim

Miles Stevenson writes:

Despite the fact that Russ is personally an economic hero of mine, an outstanding individual, and one of the most genuinely honest academics that I have ever encountered, I was highly disappointed by this podcast.

There was a little bit of skeptical push-back by Roberts, but not much. It became clear to me, especially after all the parallels drawn between Taubes' experience with his theory and Roberts' experience with Austrian theory, that Roberts was perhaps more interested in the idea that government has been giving people bad information than whether or not Taubes' grandiose claims are very well supported by scientific evidence.

After a cursory bit of minimal research, I have found Taubes to be very near a journalistic fraud. Michael Fumento of Reason Magazine demonstrated how incredibly biased Taubes' work is and can be found here: http://reason.com/archives/2003/03/01/big-fat-fake/3

Taubes can only cite a handful of studies to support his claims, yet over 200 studies have been done that do not, and are easily obtainable from medical journals and online databases. But it gets worse than that. Not only are the scientists that he quotes as supporting his theory angry at him for completely misrepresenting their views, but one of the only handful of studies that Taubes relies upon was paid for by the Atkins Diet group.

Finally, when Taubes was asked why he decided only the handful of studies he picked to support his claims were relevant, and the more than 200 other studies which do not support is claims are awkwardly missing from his analysis, he simply responds that all those other studies are biased, eluding to a mass scientific conspiracy. No evidence for the conspiracy is given. No reasons why all those 200 studies are wrong. They were simply left out because they do not confirm what Taubes wants to be true. He even goes on to say, in a response to the Reason article pointing out the cherry-picking: "...this majority has gotten plenty of space to air their views...they didn't need my help." This is being passed as good science journalism? The scientists got to have their say, I think they are wrong so I simply don't feel like acknowledging their work?

Gary Taubes wants to sell you snake oil. It is upsetting that he has twice been given a platform on a show of such honest integrity.

Rufus writes:

Actually, one of the studies that Taubes mentions most recently was the Stanford A to Z study that was funded by the NIH. It was not a long-term study, but still showed that the Atkins diet was superior to 4 other diets including Zone and Ornish.

http://jama.jamanetwork.com/article.aspx?articleid=205916

This is the type of research that he is advocating.

Miles Stevenson writes:

Rufus,

I want to re-iterate that my harsh criticism of Taubes is not that he fails to provide any studies at all to support his claim. It is mostly that an overwhelming volume of evidence that does not support his claim is completely ignored or dismissed as if it is some kind of conspiracy.

A lot of his arguments are just plain disingenuous about the current state of nutritional science. The consensus of research is not exactly that fats cause you to get fat and carbs do not. The consensus is that an excess of calories, whether they come from carbs, protein, or fat, will cause you to gain weight. He bounces back and forth between conceding this at one point, and claiming that the consensus thinks everything is about fat and that carbs are universally good at other times. This confuses the issue.

He makes strange arguments, suggesting that a lack of citation to German research is some kind of evidence that the scientific community is dubiously repressing German research. Not only is no evidence given of this, but we lose track of the fact that this is a red herring and has nothing to do with whether or not his claims are well supported by current research.

I want to make it clear that my problem with Taubes is not that he wants further research and testing to be done to investigate the claims that he brings up. My problem is the cherry-picking of data, and the odious language he uses when suggesting that government officials should apologize and accept responsibility for the deaths of anyone they recommended eat a balanced diet and exercise regularly. When he starts going down this path, he starts treading very close to 9/11 conspiracy territory.

If Gary is proved wrong, does he plan to take personal responsibility and make public apologies for anyone who may have died believing they can live on the sofa, gorging on cheese steaks?

Russ Roberts writes:

I'd like to say a few things about guests like Gary Taubes and others who say things that are not obviously true or that many of our listeners disagree with. This gives me a chance to give you my philosophy of what I'm trying to do here at EconTalk.

I have a lot of respect for you out there. I start with the assumption that you're smart and thoughtful. I don't expect you to believe everything you hear on the program, whether it comes out of the mouth of Joseph Stiglitz or Richard Epstein or me. I can't challenge everything a guest says that I don't agree. If I did, some episodes might last four hours. I assume you're smart enough and thoughtful enough to take things with a grain of salt. So I don't agree with the comments that say I have to have someone else on on "the other side." This isn't a publicly funded broadcast with a fairness doctrine. I enjoy the show because it makes me smarter. That's my criterion for a good guest. Did I learn something? Some guests pass this criterion more effortlessly than others. But most of them I learn something from. None of them are saints or prophets--infallible experts where I can trust/believe/embrace everything that comes out of their mouth. And that should be your working assumption as well. In the case of diet and health and nutrition, I have heard for years that fat is bad for us. So I don't need to have someone defend that view as a public service. Again, don't believe Gary Taubes because he's passionate and sounds smart. Keep your skepticism. But you can find alternatives to Taubes everywhere. You don't need me to provide them.

Let me say a few things about Gary Taubes. I've read both of his books. I didn't read every page--I missed a few at the end of both books. But I've read a lot of his words. He's a very interesting and provocative consumer of scientific research. He's made me think. That's the goal.

He doesn't suggest there's a conspiracy. What he does suggest is that some of the claims about health don't seem to have a lot of rigorous empirical backing of the kind we usually expect and demand from other scientific enterprises. I'm very sympathetic to this argument because the same is true of economics. There is a lot more certainty based on mediocre evidence than there should be. That doesn't mean Taubes is right. But I find it fascinating when he cites studies that he correctly points out as flawed. That doesn't mean the claims of those studies are false. They could still be true. But I think he is right about how much arrogance there is in favor of claims that have insufficient scientific support for their being true.

As I said when I interviewed him, I think he is risk of being just as cocksure of being right as the people he critiques with all the consequences that creates. When I said I wanted the theory to be true, that's because it's fun. It's fun to be a contrarian that turns out to be right. It's really exciting to think you have the theory that explains something complicated. But a smart person, like you out there, or me, realizes that the world is a complicated place, every human being is a little bit or a lot different, and there probably isn't one magic diet that leads to lean bodies that last till the age of 120. It would be cool if that were so and if we had finally discovered it. It would be wonderful if reduced carbs can reduce diabetes, obesity, and heart disease. But it may not be true. It is fascinating that it might be, and I think that is why Taubes is worth interviewing.

Rufus writes:

Miles,

If your basis for your statement is this podcast, then it should be noted that there is only so much that can be covered in a one hour podcast. In addition, because the podcast format is conversational, it isn't going to live up to the rigor of written work.

Many of the statements that Taubes makes are repetitions of things he has said previously ever since Good Calories, Bad Calories was written. That book has a lengthy bibliography, >130 references, and extensive in-line quoting.

For example, the statement about German/Austrian research being ignored is covered in a long chapter about the history of their research from the 1800s to 1940. He cites a text written in 1940 that had 191 of 587 references based on German publications. By 1949, a similar book had only 13 of 422 references. By the 1970s, no one even considered the German research... until lately where their work and theories are being re-explored. Essentially, their work pointed to hormonal factors, and that work became ignored as the gluttony theory took hold in the 1940s.

I think there are some areas of imprecision in speech that also cause confusion. When Taubes says the "calories in/calories out" model doesn't work, he has done extensive research into studies of overfeeding, underfeeding, and various mixes of carb/protein/fat.

I'll offer two paraphrased notes from GCBC to illustrate why he believes that, and then leave the rest of the research to the reader.

* American men increased calorie consumption 150 calories per day from 1971 to 2000. Women increase calories by over 350 calories." Despite men's intake of fat decreasing by 50 calories per day (meaning the increase was due to a net increase of 200 calories of carbs), obesity increased from 12% to close to 30%.

* In one diet consisting of 60% fat, 25% carb, 15% protein and a total of 1850 calories a day, weight loss was the same as another study in which the subjects ate only 950 calories a day, but the proportions were 35 / 50 / 15 respectively.

DaveM writes:

[Comment removed pending confirmation of email address. Email the webmaster@econlib.org to request restoring this comment. A valid email address is required to post comments on EconLog and EconTalk.--Econlib Ed.]

Miles Stevenson writes:

Russ,

Maybe I'm only hearing what I want to hear. Or, more precisely, maybe I'm only hearing the most provocative interpretation of what is being said. If anyone has influenced me to slow down and re-examine my own passions and biases, it is you Russ.

I certainly don't mean to be harsher on the show than is warranted, or turn a disagreement about the content into a flaming ball of vitriol. Perhaps that is what I have done, and if so, I apologize for that. I intended to thoughtfully disagree, as opposed to launch a holy crusade. I do hope my comments are taken in that spirit, even if I have failed to express myself as such.

Thanks for the response and, above all, thanks for Econtalk.

Greg writes:

As an obese physician I have a vested interest in these issues. 30 years in practice leads to the conclusion that the conventional nutritional wisdom seems useless. The results of intervention tends to be short term. We need better studies. Unlike alcohol and nicotine you cannot give up eating permanently. The futility of conventional advice leads to the mistake of thinking the latest unconventional approach must contain the answer. My understanding is that Calories(Kcal actually) are measured in the laboratory based upon burning. Biological processes are not the same as burning in a calorimeter. The obesity problem is complex.

P.S. I LOVE econ talk.

Miles Stevenson writes:

Greg,

One thing that I believe is worth pointing out, is that personal experience is just about the worst possible way to do science. In other words, it makes very poor evidence.

I'm not ascribing this view to you. I'm not saying that you believe personal experience to be good evidence. I just think it is worth mentioning because so many people react to these kinds of stories with their personal experience: "I've lost 20lbs since I started the Atkins diet!", etc.

This is inadmissible as evidence to a scientific journal (at least it should be), and in my opinion, should be inadmissible in casual discussions of the evidence as well. I've always believed that best way for even lay-persons to discuss scientific issues, is for everyone, even the musicians and the cab drivers, to put their academic hats on and participate in the discussion using a stricter set of cultural norms than usual.

DaveM writes:

Gents:

It seems to me that Austrian economic principles might bear on this topic as well. Order emerges from the marketplace of ideas and practices!

Low-carb-ism has been tried in the marketplace and found wanting. It had a fair trial - it was an enormous fad and even had a cultural icon (Dr Atkins, whose name even blessed some menu items at chain restaurants)- but like every weight loss miracle in recorded history, it faded into cultural background noise.

IF low carb dieting worked, the marketplace of ideas should have caused asymptotic increase in its use and other weight loss strategies should have been unable to compete.

This did not happen, and to be intellectually honest we should admit the obvious verdict. Despite the appeal of the idea and the supporting story that can be constructed around it, low carb dieting does not work.

Posted by
DaveM

Aaron writes:

Why we get fat is a very interesting book to read. I have adopted a Paleo diet after reading Tim Noakes book , "challenging beliefs". Noakes memior "challenging beliefs " is in the same vein as Taubes. Taubes mentions Noakes during the interview and I think it would be great to get Noakes on econtalk. His latest book, "waterlogged " challenges the long held belIef that endurance athletes need copious amounts of water and sodium during completion. He points to the bodies way of conserving salt and the studies that back him up.

Rufus writes:

DaveM,

You raise some good points about the marketplace of diet ideas. However, you did not mention the interventions in the market such as the Food Pyramid, the American Heart Association's Heart Health low-fat diet, endless reports from observational studies saying that low-fat, high fiber diets are healthy and that red meat kills, saturated fat is a demon, and cholesterol is evil. (I will resist providing links that refute all of those points)

Also, the availability of food is a signficant factor. If you've seen Michael Pollan's films or books, you'll understand the rules of the game are to avoid processed foods and shop the perimeter of the grocery store. However, the vast majority of the population does not follow that advice.

I believe that we are at the start of a market shift. 5 years ago, there were hardly any organic foods in my local grocery and grass fed beef was not for sale. Now the organic section is almost an entire aisle and grass fed beef is in most stores. Vibram 5 toed shoes are everywhere, too.

I also foresee a coming battle with scientists and government officials taking sides. For example, recently there was a new story about Bill O'Reilly taking wheat out of his diet and losing weight. In the article, the Kansas farmer was worried what would happen if people didn't eat wheat, and a non-Taubesian nutritionist stated the health benefits of wheat. I'm on the side with Taubes and others who are avoiding grains and think that there is science to support that claim. However, I have a dilemma between trying to convince people not to eat carbs and my personal economic interests of keeping the demand for the food I prefer low so the price is cheaper. Ultimately, I can't imagine that the political pressures would ever allow a statement of "wheat kills" to come from the government, but then again, as with smoking, we might eventually see that.

Anecdotaly, I finally convinced my parents to go grain-free / low carb and they lost 15 and 8 lbs in the past 6 months, have higher HDL, and my mother's high blood pressure has dropped 10 points.

Doug writes:

Greg,

It is my understanding that metabolism is, in one way, very much like burning something in a bomb calorimeter. That is, the *overall* reaction taking place in metabolism (cellular respiration) is the oxidation of the ingested contents. A calorimeter's job is to measure heats of reaction that can be used to understand the thermodynamics of the reaction pathways (e.g. the Krebs cycle). However, it is clear that human metabolsim is a distinctly more complex network of reactions and physical processes, which are internally regulated.

Doug

David F writes:

I did enjoy this podcast but since this is an economics podcast it might have been interesting if the discussion touched upon the many interventions and involvements of government in this field.

Sash writes:

GT's own summary:
If your goal in reading this book is simply to be told the answer to the question “What do I do to remain lean or lose the excess fat I have?” then this is it: stay away from carbohydrate-rich foods, and the sweeter the food or the easier it is to consume and digest—liquid carbohydrates like beer, fruit juices, and sodas are probably the worst—the more likely it is to make you fat and the more you should avoid it.

This Makes Sense:
Refined sugars and flours are not healthy foods. They drive up the body's insulin response, which in turn leads to more conversion of food to fat and increases insulin resistance over time.
Illustrates his point well with photos.

This doesn't make sense:
Eating fat without restriction is OK if you shift to a "no"-carb diet.

Skeptical about:
When you are hungry eat as much meat as you want until you are full. What does this do to heart health?
Cut back on fruits and vegetables that have higher fructose content. What about fiber, minerals and nutrients your body could use? GT is dismissive of their benefits.

David B. Collum writes:

When keystroke and--"poof"--the post disappeared.

[Huh? If you had a problem posting a comment, email me at webmaster@econlib.org . I'm not sure what you are talking about.--Econlib Ed.]

Joe Marquez writes:

After hearing several podcasts on Econtalk about health and weight loss, I think it would be beneficial to hear what a personal trainer or a nutritionist would have to say. What I found (from online research and through fitness professionals in my gym) most interesting about diet and exercise is that most agree on eating 5-7 small meals every 2-3 hours a day using high-nutrient high-protein, low-carb low-fat low-calorie diet to shed body fat (weight may increase if one is on a mass-building routine/lifestyle or decrease with cutting routine/lifestyle). Not sure of the long-term (>20 years) effects, but this works.

I am very skeptical about the 1 meal per day diet as that type of diet/lifestyle is not practical for most people. Periods of starvation will slow down metabolism as the body will want to conserve energy (fat). The 5-7 meals per day recommended by fitness trainers may also be impractical to maintain because of work/life schedule.

Every body and their metabolic rate is different and reacts differently to different diets and exercises.

Robin writes:

I see a lot of people who think that podcasts they agree to are good and podcast they disagree with are bad. This is very bad habit. I have it also but I try to ignore it as much as I can but, but I know I prefer to listen to podcasts I agree with :(

Rufus writes:

What I find most fascinating about the comments on this podcast or comments on similar articles I run across in the media is the pervasive nature of certain themes. In some ways this is much like the Keynes vs. Hayek battle.

Here is a quote that illustrates the Hayekian view of nutrition from a blog post by Dr. Natasha Campbell-McBride.

"... no clever doctor or scientist and no clever book can calculate for you what you should be eating at 8am, or 1pm, or 6pm or in between. Only your body has the unsurpassed intelligence to figure out what it needs at any given moment of your life, as your nutritional needs change all the time: every minute, every hour and every day."

full article:

http://www.doctor-natasha.com/feeding-versus-cleansing.php

What I've most learned from Econtalk and Russ' interviews of Taubes and similar podcasts (Ed Yong, Matt Ridley) is to be skeptical of scientific studies and especially the way they are reported in the media. Often, we'll hear about "xyz increases the risk of cancer by 23%", but if you read the study, the increase is relative to a baseline incidence of 1.0% (or less). This is the type of science that condemns red meat:

http://www.zoeharcombe.com/2012/03/red-meat-mortality-the-usual-bad-science/

While studies that "prove" vegetarian diets are healthy ignore the high correlation of consumption of wheat with heart disease and obesity and cancer.

http://rawfoodsos.com/2010/09/02/the-china-study-wheat-and-heart-disease-oh-my/

http://rawfoodsos.com/2010/07/07/the-china-study-fact-or-fallac/

In the end, we're all a study of N=1, so perhaps the best advice is from a Chinese saying:

It's better to eat the wrong thing with the right attitude than the right thing with the wrong attitude.

Perhaps there are animal spirits after all.

Steve writes:

To Greg, the "obese physician," I have a question: What part of the "conventional nutritional wisdom" seems useless to you? If I were to summarize that "wisdom," it goes something like this: Eat a "balanced," unrefined diet of mostly vegetables, legumes, whole grains, fruits, with some meat or other protein sources, and some healthy fats. Don't overeat, get adequate exercise and sleep. Cut way, way down on refined carbs, drink enough water. So what part of that is "useless"? Is there any evidence to indicate that adhering to this plan would lead to obesity, especially if followed from childhood? Why do so many Americans - even Russ! - feel "excited" about "contrarian" ideas to supplant the "conventional nutritional wisdom"?

To Miles, DaveM, and Sash, I enjoyed your comments and I agree with you. And to Robin, I disagree with your point about not liking podcasts we disagree with. Podcasts, and Life, would be pretty boring if everything was always agreeable. :-) Anyway, it's not that we "dislike" Taubes' ideas. It's just that Taubes comes across as a bit more certain and antagonistic than the data and evidence entitles him to be. I think Russ mentioned the word "cocksure." Taubes has NOT made the case that healthy people eating a HEALTHY diet which includes unrefined carbs leads to weight problems. Moreover, Taubes seems to ignore data and evidence which contradicts or challenges his ideas. That's the worst kind of "science" and Taubes, being a science journalist, knows better. There are all sorts of reasons why a diet which eliminates all carbs might help overweight people lose weight, but that doesn't mean it's the healthiest way for most people to eat.

When Russ said that there is no rigorous empirical evidence for claims about health, I don't know what he means. Maybe Russ is making the same point as the obese physician, Greg, about conventional nutritional wisdom being useless? I can guarantee that if you take a hundred healthy kids who really follow all the "conventional" health guidelines, as promoted by various agencies, groups, and associations, you will end up with a hundred healthy kids. The main problem is that too many kids (and adults) don't follow the conventional guidelines.

And finally, I think Russ misunderstood what people mean by wanting to have a "real" nutritionist on the show. We aren't looking for "balance" per se and we aren't looking for someone to tell us that too much fat is not good for us or unrefined carbs are okay. If Russ is going to have a nutrition show with a contrarian outlier, then it's natural for an intelligent and skeptical audience to want to see how an expert would respond to Taubes' ideas. It's unfair for Russ to compare a one-off guest like Taubes with his economics podcasts. We get plenty of economics viewpoints just by listening to Econtalk each week. One week Russ may talk about Keynes and the next Hayek. Or he might even rap about them. :-) We won't get that opportunity with Taubes. And I don't think it's fair for Russ to say that he is just "having fun" and "learning" with Taubes. Russ told us that he has been following Taubes' guidelines in order to lose some weight. I think Russ said he lost something like twenty pounds. And that's good. But millions of people have lost millions of pounds on all sorts of diets. It's possible that for losing weight some diets are better than others. But I make distinctions between overweight people losing weight and healthy people staying healthy. It's not the same thing.

Steve writes:

Last night I watched an hour-long discussion/debate between Gary Taubes, Dr. Dean Ornish, and Dr. Barbara Howard, moderated by Dr. Oz. It's easy to find on the Internet.

It may sound unkind, but my honest overall impression is that Taubes came across as a jerk. I don't use the term "jerk" lightly. I was also not impressed with Taubes' standards of science journalism. He obviously had an agenda in the discussion, with very little evidence to back up his claims. At times Ornish would trot out some piece of evidence and you'd see Taubes smirk at it. My opinion has nothing to do with how I feel about Dr. Ornish or Dr. Howard. To be honest, I'm not a fan of Ornish's ultra low-fat recommendations, though I acknowledge that his diet may be beneficial to some people, including those with certain health issues.

Taubes did not come across as a jerk on Econtalk. As Russ said, he came across as "passionate and smart." Of course, it wasn't Dean Ornish who interviewed and challenged him. :-)

Jay Balapa writes:

I fall in the camp of our Genes determine our weight.

Based on your parents weights if you on average destined to be 200pounds then your diet can force to be between 180 to 220.

Anything below 180 you need to be in constant starvation mode to keep that weight off.

Anything above 220 you could easily shed those extra pounds by slight dieting.


Everything else is just marketing.


Only point I want to make is that when Russ challenged Gary about that natural weight of human beings regulated by thier Genes and

Rufus writes:

Jay

Your point about genetics got clipped, but one part of the story is why do children grow taller and not fatter? It is because they are genetically programmed to do so, and hormones also play a key role.

If that is true, then why in less than a generation has the rate of obesity sky rocketed? Clearly that is not possible due to genetics, so it must be something in the environment that changes gene expression.

Here is an alternate theory from a Boston U researcher who "... suspects that background levels of certain food additives could cause subtle but critical changes in our metabolic tissues, possibly contributing to diabetes and obesity."

http://www.bu.edu/bostonia/winter-spring12/corkey/

Steve writes:

Rufus, that's an interesting article about Dr. Corkey's research, but unfortunately it didn't have much definitive information. She's 73 and I hope she has many years left to continue her research. For some reason I've never thought it was "normal" for scientific researchers to retire, because I imagine that their work is fun. :-)

Dr. Corkey suspects that a class of widely used emulsifiers called monoglycerides, often found in processed baked goods, might affect beta cells in the body in a way that contributes to weight gain. Of course, if someone was overweight, he should eliminate processed baked goods from his diet anyway - that's a no-brainer!

I thought the remark Dr. Nestle made was both true and funny: “It’s an Occam’s razor situation—the simplest explanation is often the one that works. I still vote for calories, but that, of course, doesn’t give researchers much to do.”

Rufus writes:

Steve,

For me the irony of the article on Dr. Corkey was that after explaining how novel her research is, the counterpoint was from a "We-get-fat-because-we-eat-too-much-as-you-will-read-in-my-new-book" doctor.

Probably no confirmation bias there. I wonder what he does all day since there's no research to do.

Steve writes:

Rufus, now that you point it out I can see the irony. Apparently there are so many competing theories as to why we get fat that we're now getting books to remind us that eating too much is still one of those theories.

Regarding confirmation bias, it would be all too easy to define an overweight person as someone who eats too much. I suppose we can soon expect to see books about the health benefits of bulimia and anorexia, if done properly. :-)

Rufus writes:

Here's a good recent study on the role of dense carbohydrates and leptin resistance. It also has a table of a lot of the populations that Taubes mentions, what they ate, and whether they were lean or obese.

"Despite food abundance and a clear overlap of macronutrients and glycemic index with Western diets, Kitavans are reported to possess leptin levels, fasting insulin, and blood glucose levels dramatically lower than those in Western populations deemed healthy, and appear to have a virtual absence of overweight, diabetes, and atherosclerotic disease. Environmental or genetic explanations for this metabolic health appear unlikely, since islanders who leave for the mainland and eat Western foods become overweight."

http://www.dovepress.com/comparison-with-ancestral-diets-suggests-dense-acellular-carbohydrates-peer-reviewed-article-DMSO

Doug writes:

I eat a fairly low carb diet, but my mom always points that a billion (thin) Chinese have subsisted mostly on rice.

Stevie writes:

FYI: I'm changing my name from Steve to Stevie in order to distinguish myself from other Steves in this forum. And if there are other Stevies, I'll change my name to Stevie Wonder. :-)

Rufus:

I read the abstract to the article you cite. I don't know if you read the entire article? I think I understand some parts of it but not others. The part about "dense acellular carbohydrates" (i.e. sugar and flour) causing obesity seems clear enough, and I think everyone agrees on that point. I have questions about the following:

"The obese homeostatically guard their elevated weight."

This reminds me of the so-called set-point theory of weight maintenance. Many books have been written on how we can alter our set-points. I'm not sure how that theory stands today.

"low-carbohydrate diets spontaneously decrease weight in a way that low-fat diets do not."

I don't know what he means by "spontaneously."

"Nutrition transition patterns and the health of those still eating diverse ancestral diets with abundant food suggest that neither glycemic index, altered fat, nor carbohydrate intake can be intrinsic causes of obesity, and that human energy homeostasis functions well without Westernized foods containing flours, sugar, and refined fats."

Okay, so here it sounds like he's saying that as long as we avoid flour, sugar, and refined fats, we'll be okay. I'm assuming that "refined fats" include butter and oils, including olive oil?

"A diet of grain-free whole foods with carbohydrate from cellular tubers, leaves, and fruits may produce a gastrointestinal microbiota consistent with our evolutionary condition."

Here he seems to be saying that we should avoid whole grains (and legumes, too?), but it's fine to eat "cellular tubers" (i.e. potatoes, yams, etc.). Why is that? It's inconsistent with his statement that carbohydrate intake is not an intrinsic cause of obesity. If that is true, why are whole grains (and legumes) bad? Also, if we're supposed to avoid whole grains, then telling us to avoid flour is redundant.

Doug:

The Chinese eat a lot of white rice and most are slim, as you say. I have a killer recipe for rice pudding. I mean, no one makes better rice pudding than I do. But it's very rare that I will see a Chinese person willing to eat my pudding. Most of them don't even want to take a little taste of it because the very thought of making pudding from rice seems disgusting to them. Judging from their facial expressions you'd think you were offering them a raw dead rat! I've been willing to eat a lot of disgusting Chinese delicacies, so I don't know why they have such a problem with rice pudding. :-)

Rufus writes:

Stevie,

Here are a few responses to your questions, but first I have been inspired to re-read some sections of Good Calories, Bad Calories. As to the debate about calories in/calories out, research in the 1940s on mice and rats focused on the role of the hypothalamus in regulating homeostasis (and hunger). These mice or rats either had tumors or surgical procedures performed to damage the brain. What was the result? In one study, mice gained 6 times as much weight per calorie consumed vs normal mice. This line of research died (the researcher Ranson died in 1942) and soon after focused shifted to psychological studies about why we eat too much.

So, isn't that fascinating? 6 times as much weight per calorie consumed?

Okay, on to a few of your questions. On the topic of oils, here is a link that covers that topic and grains / wheat as well.

http://chriskresser.com/9-steps-to-perfect-health-1-dont-eat-toxins

People in the Paleo community refer to "industrial seed oils" like canola, soy, corn, and others with great derision. They have way too much Omega 6 for a healthy diet.

Olive oil is on the border line, but go for unfiltered, cold pressed if you can find it. There is a great chapter on oils in Paul Pitchford's book called Healing with Whole Foods. (that book also has a lot of information on Chinese medicine, which is quite different than the Western cause-and-effect approach).

With Oils, people don't realize the chemical treatment process and high heat that damages most oils that you see in the grocery store. Just to keep a little economics in this discussion, you get what you pay for... Don't expect to find healthy food for the same price as mass produced and processed foods. I cook with coconut oil and ghee mostly.

Paleo people also hold Wheat with special caution due to its toxicity. For example, brown rice and quinoa are also somewhat toxic, but there is no Celiac disease like there is with wheat. Wheat is mentioned in the link above, but for more, and to see a researcher who has identified over 50 compounds in wheat that are damaging to our health, read this about Dr. Fasano's research.

http://www.healthy-eating-politics.com/autoimmune-diseases.html

On the Chinese eating tons of rice, keep in mind they consume very little refined sugar. Also, they have a very active lifestyle (by necessity). However, that is changing as the Western diet has entered into the large cities in China. For example:

"Sweets can move from an occasional treat to a daily indulgence. Portion sizes are getting bigger, Western-style food is widely available in the urban areas, and people are eating out more often."

http://www.pbs.org/newshour/rundown/2010/06/reporters-notebook-obesity-rising-in-china.html

Maybe global trade is good for some things, but the spread of the Western diet appears to have a pretty high economic cost for those who suffer its consequences.


Stevie writes:

"So, isn't that fascinating? 6 times as much weight per calorie consumed?"

Yes, it is fascinating. And if it's true, the first question I would ask is: In a normal mouse, what does the body do with those calories if they don't go toward weight gain? In a damaged mouse, is adding weight "prioritized" at the expense of other physiologic functions, or does the body somehow become more efficient (which, under certain circumstances, might confer a survival advantage)? And why on earth would such interesting research stop merely because the initial researcher died?

Thanks for the info on oils and wheat. Regarding Chinese eating lots of white rice, I will point out that, if I understand Taubes' theory correctly, he would predict that even if the Chinese are physically active they should still get fat. Carbs - especially refined carbs - are the enemy, he seems to say. I'm pretty sure I heard Taubes say that even marathon runners will get overweight if they eat carbs. Conversely, I seem to recall Taubes saying that, if we don't eat carbs, we won't get fat even if we're not physically active. Am I missing something?

Rufus writes:

One of the issues that we face is that not all carbs, fat, or oils are created equally. So, for example, rice is much "safer" than high-fructose corn syrup or complex carbohydrates from refined grains.

Since most diets contain a mix of all types, the ratios play a big role. When Taubes mentioned the marathon runners, he was perhaps referring to a study where obese people trained to run a marathon successfully, and yet the average weight loss was either zero or two pounds (can't quite remember). So, that is pointing to the irrelevance of exercise and weight loss more than the carb theory. However, those people were not on a low carb diet.

As to the mice and rats, yes, absolutely their bodies were prioritizing the storage of fat over other metabolic functions. There are other studies where they die even though they are obese due to the misallocation of the nutrients. (Muscles actually contain a large amount of fat, so if they mice are metabolically deranged, they can end up depleting themselves until their hearts stop while still gaining fat).

Also the research pointed out was that homeostasis was affected because the mice slept more and were less active. This is more the set point theory. In other words, the effect of becoming obese had consequences for other autonomically regulated systems.

Stevie writes:

"So, for example, rice is much "safer" than high-fructose corn syrup or complex carbohydrates from refined grains."

That may be, but I'm trying to see things from Taubes' point of view. If I understand him correctly, white rice should be a big no-no. Even unrefined, complex carbs in moderate amounts are bad. The only carbs that are "safe" are those found in non-starchy vegetables, such as leafy greens, and then only if eaten in limited amounts. By the way, as I understand it, refined grains are not considered to be complex carbs.

"When Taubes mentioned the marathon runners, he was perhaps referring to a study where obese people trained to run a marathon successfully"

Perhaps. He said something to the effect that even some marathon runners were overweight because they ate too many carbs. Putting it that way implied that they had already been seasoned runners rather than people who were already obese but training to run marathons (in an attempt to lose weight?). But yes, since he didn't elaborate, he could have been referring to the study you mention. I will be honest in saying that it would absolutely amaze me if it turns out that for the average person exercise is "irrelevant" to weight loss. Or weight gain, for that matter (if you are working out to build muscle).

"There are other studies where they die even though they are obese due to the misallocation of the nutrients."

Well, there you go. In a way, then, it seems like the fat tissue is acting a bit like a cancer, growing out of control at the expense of the rest of the body.

"The mice slept more and were less active."

So while the body was conserving energy for other functions, that left more energy to be converted to fat. Now, if they could only figure out how to cause the opposite effect, preferably by taking a pill! :-)

John writes:

Floccina: pets foods are supplimented with grains. They are very high carb.

100% of the people I follow who reduce carbs have lost weight, many tremendous amounts. I have as well. And the interesting part is our lipid profiles improve. Here's mine.
HDL 112
LDL 70
TG 39
CHOl 191

Stevie writes:

John,

I'm a pragmatist, and for me the most practical theory is that if people limit or eliminate refined/processed foods and don't overeat, they'll be okay as far as food goes. Another practical benefit from such a practical theory is that it allows for a huge variety of delicious foods. I'm skeptical about any theory claiming that unrefined carbs are unhealthy.

You lost a lot of weight on a reduced-carb diet and your lipid profile is pretty good. That's great!

There was a recent news article about the higher rate of obesity in American pets. It's been said that masters often start to resemble their pets. In this case, the pets are starting to resemble their masters. :-)

Tim Noakes writes:

As someone who credits Gary Taubes with "saving" his life, I am perhaps not one to be completely objective in this matter. What Taubes taught me was what 40 years in medicine did not. It is also the key point of his message that has not been picked up by too many in this discussion as far as I can see. Specifically it is that his ideas apply to those who like me are carbohydrate intolerant/resistant and on the road to developing full-blown Type II diabetes. When we ingest carbs we oversecrete insulin, our blood glucose rises abnormally, we develop a triglyceridemia and de novo lipogenesis is activated. Our appetite is stimulated and 3 hours later we must eat again. These responses do not occur to anywhere near the same extent in those who are carbohydrate tolerant (although the hunger cravings might). So his message is perhaps of less relevance to those who are carbohydrate tolerant. But to those like me his message is literally lifesaving.
The change in my enjoyment of life, in all my measures of health and in my running performance produced by following his advice has been utterly spectacular - changes that I would have considered utterly impossible at age 63. On a high carbohydrate "Prudent" diet with lots of "healthy" wheat and cereals and little fat I was fat, weak, lazy and barely able to run anymore.
The cost of this miracle cure? Simply cut total carb intake to about 50 grams per day.
To say that the cause of obesity (and Type II diabetes) is not known and that there is no cure is in my mind disingenious. For those like me who are carbohydrate intolerant/resistant, the answer is almost too simple and too obvious to be believable. That perhaps explains Taubes' frustration that something so obvious cannot be "seen" by most nutrition scientists and the science they advocate.
Perhaps Taubes is "only" a journalist. But he taught me more about nutrition and my own physiology than had 40 years of interaction with all the medical experts I have ever spoken to.

Vlad writes:

More excuses for fat people? really? I have listened to your show for months now, and I have never stopped mid-show. But this drivel is pathetic.

Isn't it weird how a society that doesn't exercise, drives everywhere, eats garbage from fast foods which has no nutritional value, vitamins or fibre, starts getting fat? I guess it's MAGIC! Or a "complex system"... yeah sure it is. Go ahead and tell yourself this while you're eating at another all-you-can-eat buffet, or having your extra-large meal.

Shame on you Econtalk for promoting this pseudoscience.

Rufus writes:

Breaking news...

http://grist.org/scary-food/2011-03-04-low-fat-diet-fad/

Dr. Dariush Mozaffarian, who codirects the program in cardiovascular epidemiology at Brigham and Women’s Hospital and Harvard Medical School and is an assistant professor at the Harvard School of Public Health, was also there and said, “No randomized trial looking at weight change has shown that people did better on a low-fat diet. For many people, low-fat diets are even worse than moderate or high-fat diets because they’re often high in carbohydrates from rapidly digested foods such as white flour, white rice, potatoes, refined snacks, and sugary drinks.”

These are clear indications that an important tipping point in the mainstream understanding of fat and nutrition is underway. But it did take some time. Back in 2002, Gary Taubes wrote about it in The New York Times magazine, laying out a fine deconstruction of the low-fat premise presented to the American people. He pointed out that the science behind this recommendation was never proven and was actually based on “a leap of faith”

[Comment reformatted for clarity. Emphasis is Rufus's.--Econlib Ed.]

Stevie writes:

Rufus, I suspect that even Dean Ornish, if given a choice between a "low-fat diet" including lots of "white flour, white rice, potatoes, refined snacks, and sugary drinks,” or a moderate or high-fat diet, might choose the latter. :-)

Sometimes I hear Taubes claiming that we've been told high-fat foods have been making us fat, but I don't think that's a fair statement. From what I've seen, for decades now the focus has been on refined and processed carbs and an appalling lack of even moderate exercise. Over-consumption of saturated and trans fats have been mentioned mostly in regards to coronary and vascular disease. Of course, regardless of one's opinion on butter, for example, most everyone can probably agree that eating a few slices of white bread with half a stick of butter is not particularly healthy. But it sure does taste good, doesn't it? :-)

Dr. Duru writes:

I read and scanned through these comments and was relieved to find that others hold some skepticism about Taubes' theories. And thank you Professor Roberts for posting an explanation for why it is valuable to have someone like Taubes on the show (although like another commetor, I don't think he needed to come on twice in less than a year).

I like that Taubes has opened my eyes to all the flawed health research out there and the even more flawed interpretations of that research. I am a better skeptic because of it. But I was left wondering whether Taubes had fully considered cases that directly contradict HIS assumptions. Surely they are out there. For example, if carbs are so bad for us, why have rice and potatoes and yams been such an important staple for civilizations for centuries from Asia to Europe to Africa? Surely, there are populations we can find on these continents where people ate a high amount of carbs, worked hard (or not), and stayed nice and lean. Or is Taubes implicitly stating he does not believe any examples exist?

From Professor Robert's questions and discussion about genetics, I actually had to wonder more strongly whether genetics is actually the key factor. If so, then it is more important to understand your own body and metabolism and eat accordingly.

I personally marveled at how quickly I lost weight once I eliminated almost all "extra" sugary foods from my diet last year. I lost 20 pounds or so within less than 5 months. However, I also increased my exercising. Over 15 years ago, I made the decision to severely restrict my intake of carbs through starchy foods like pasta and rice, but I never noticed much change in weight...even when I was playing soccer and working out regularly. Am I to then conclude that I would have been even fatter? I don't know!

In the end, I am left with theory to do whatever works. :)

I also think economic trade-offs are real, and I thought Professor Roberts would go there in more detail. Is it worth a few extra pounds and a few years less of life to enjoy potato chips for decades? I can definitely see someone making that conscious choice!

I look forward to having OTHER experts talk about this topic. Surely there are other contrarians who have a different point of view than Taubes...

(Finally - I also liked hearing Taubes accept the possibility that his next research project could prove him wrong and the "conventional wisdom" correct.)

Dr. Duru writes:

Oh yeah - and thanks to those of you pointing to Guyenet's work. Great stuff.

Rufus writes:

To all those who listen to this podcast and question whether

... Taubes had fully considered cases that directly contradict HIS assumptions.

I can only recommend that you read Good Calories, Bad Calories.

Or look up Matt LaLonde, Chris Masterjohn, Mark Sisson, and many others who have dialed in on the science behind this "alternative" view of diet and metabolism.

In fact, I'm currently reading Natasha Campbell-McBride's book called "Put Your Heart in Your Mouth". The first chapter is about myths, and it has 32 points with dozens of studies of support that are in opposition to the conventional wisdom.

Examples:

Eating fat is protective
Low cholesterol increases mortality
Cholesterol is heart protective
There is no correlation between cholesterol and atherosclerosis
Low consumption of animal fat is associated with higher cholesterol
People with normal cholesterol die from heart disease at just as often as those with high cholesterol

and on and on.

Stevie - throw away the bread and eat that stick of butter!

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