Russ Roberts

De Vany on Steroids, Baseball, and Evolutionary Fitness

EconTalk Episode with Arthur De Vany
Hosted by Russ Roberts
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Arthur De Vany, of the University of California, Irvine, and creator of Evolutionary Fitness, talks with EconTalk host Russ Roberts about performance-enhancing drugs in baseball and Evolutionary Fitness, De Vany's ideas about diet and fitness. In the first part of the conversation, De Vany argues that there is little physiological or statistical evidence that steroid use increases home run totals in baseball. The second part of the conversation turns to De Vany's theories of diet and exercise. De Vany argues that our diet and exercise regime should take account of our evolutionary origins, an earlier time when we ate no grains and our exercise was a mix of intense activity punctuated by much milder activity. He argues that jogging is unhealthy and that we would live longer and feel better if we followed a different exercise routine than most Americans do today.

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0:36Intro. [Recording date: March 23, 2010.] Topic is what Art finds interesting--baseball, fitness, movies. Start with baseball. Start of the season is just around the corner. Forthcoming paper at Economic Inquiry on relationship between steroid use and homerun hitting; skeptical of the mainstream view that steroid use has had a big influence. Why a skeptic? "The data made me do it," as my professor, Armen Alchian used to tell me. That there is any such thing as performance-enhancing drugs is largely a myth, not supported by any strong evidence--other than some dehydration, which tends to increase the number of red blood cells in the blood, which helps endurance matters. Most publically-identified users of steroids--let's use the term "performance-enhancing drugs" because besides steroids there's HGH and who knows what else--are Barry Bonds, Mark McGwire, Sammy Sosa. Very large people, which people assume help them hit them home runs; and they did have a lot of home runs. Mass does help people hit home runs. Babe Ruth weighed 251 pounds. At equal bat speed, a more heavier player will add about 30 feet to the length of the hit. Hank Greenberg, Babe Ruth, Steve Bilko, Dick Stewart who I played with, all large. Mass does help, but you have to have the fine coordination and timing and precision of the swing path in order to make good contact with the ball. Contact dominates in how far the ball is going to go. So does backspin--you have to hit the ball on a slight uppercut so that it carries. Hank Aaron was not a very massive player, but he hit more home runs than anyone. To build upper body mass, steroids are not really proven to be effective at that; the increase in lean body mass that does sometimes result from a combination of hard training and steroids is primarily slow twitch muscle fiber, not the fast muscle fibers that impart strength and quickness to an athlete. Second point is that there were many steroid users, it was widespread in the minor leagues and we never heard of these guys. A few examplars who hit a lot of home runs is bad statistics, cherry picking over the sample. How many failures were there? Failure rate was enormous. If you look at what Cole and Stephen Stigler--George Stigler's son--did, with the evidence they were able to amass with known steroid users was the hitters suffered a slight decrease in performance. Who would be the people who used steroids? People near the end of their career; people under enormous pressure to hit home runs, like A-Rod; or they were injured. Selection bias for steroid users turns out to be primarily people who were injured or at the end of their careers.
5:52Clarify: Mass helps you hit home runs. Clear that many baseball players use weight training to increase mass, especially upper body. Did steroid use not enhance that weight training? Taken together, steroids and weightlifting has a checkered history. In some instances, particularly for power lifting, massive amounts of training and extreme overuse of steroids does result in larger body mass, but all that body mass is slow. You can make an equivalent gain in body mass as a baseball player without using steroids. All you have to do is work out. Mark McGwire is no less massive now--have you seen him? He's gigantic. Muscle mass he built early in his career--by the way, his brother is a body-builder. In his rookie season--hit 48? extraordinarily successful rookie season--if you look at pictures of him he was quite small. Partly your point. A thin, unmuscled person, Ted Williams, Lou Brock, can hit the ball a long way without lifting weights, without steroids. McGwire, Bonds clearly changed their upper bodies. Are you saying that steroids didn't help that, and are you saying that to the extent their upper bodies did grow, it didn't help them hit home runs because it didn't help their bat speed? Didn't help their bat speed. We know that muscle bulk--the kind created by weight lifting, body-building, where the only research has been done--helps you build slow twitch, not fast twitch muscle fibers. Helps you lift a 400-lb. bat or 200-lb. baseball, but doesn't help you swing the bat quickly. If you look at McGwire's record--he hit .3 homeruns per hit--even when he first broke into the league. Over his whole career he hit .36 homeruns per hit--one measure of his power. He had a few peak years--in his last year, 2001, about half of his hits were home runs. By that time, he had perfected the new modern swing. Technological change in baseball: in the Charley Lau swing, which George Brett used to great effect and is now essentially the swing that is used, they don't rotate the forearms and pull the bat off line. If you look at Mark's early career, he's a leaned-back, rollover-forearm type of hitter, which alters the swing path of the bat. In the later years of his career, he probably had the most beautiful swing in all of baseball. Long extension, with backhand off the bat, and the bat following the line through the strike zone for a much longer period of time, followed by high finish, which depicts the rotation and the swing path as a more upward swing path. He's a hitting coach now. Sammy Sosa would probably not be used as a model of a proper swing, though in his years, his swing had a very fine motion to it, too.
10:30Talk about Barry Bonds for a minute. Issue of slow-twitch versus fast-twitch muscle. A lot of people point to his success as being tied to steroids because of his success at such a late age. Could be just an outlier--possible. Two things about him: speed of his swing--look back at his earlier years; never saw him much when he played for the Pirates, compared to his later success. Did his bat speed change later in his career? Second, often neglected, is how rarely he missed the ball. In his later years, he was walking 200 times roughly a season--roughly almost a third of the time, choosing not to swing. When he did get a pitch in the strike zone or a pitch he chose to swing at it, he rarely missed it. Nothing to do with steroids. Is that correct? Yes. He only struck out 47 times in 2002, for example; 58 times in 2003. Unheard-of records. Ruthian numbers--Ruth rarely struck out. Bonds has always hit for a great deal of power. Line drive hitter when he came out. Altered his swing and went to the modern uppercut swing maybe in the year 2000 or so, maybe 1998. His home runs per hit haven't changed much: the average of .26 home runs per hit over his career, with one large outlier in 2001, .47, which McGwire exceeded. Williams over his whole career hit something like .33 home runs per hit. So, Bonds had a really exceptional year; primarily because he let his strikeouts drift up greatly, up to 93. His peak performance relative to his entire career is still not like the exceptional outlier that Roger Maris's 1961 home runs was. These peak performances are in some respects unexplainable. Rely upon chance combination of many small factors. Brady Anderson? We know he would have had acne; small testicles--don't think everyone would think that; baldness they took as a symptom of steroid use, but very little evidence that steroids cause baldness; connective tissue issues can sometimes be attributed to steroids. Steroids are not just a wonder drug. They do all kinds of bad things for the body. Alter protein synthesis, do all kinds of bad things to the muscles--rip tendons, tear knees out. Not a magic pill. Can't take a lousy hitter, put steroids into him, pump him up with muscle, and turn him into having a fine swing. Rare, exceptional talent. Very few people do it well. Expect extreme variations in outcomes--that's just how peak performance is. Publishing: half the papers in a department are written by the square root of the number of participants. Human productivity. A few people are the exceptional publishers in a department or the exceptional hitters in the major leagues. Just like George Stigler or Armen Alchian or Paul Samuelson--you don't expect them to do 5 great papers a year; expect some years of extraordinary productivity and other years of not such high productivity. This is the way genius is. These hitters are the Bach, Mozart, and Beethoven of home runs.
16:42Data and evidence more generally. One thing people forget when looking at data is other things going on in the background. Confirmation bias seeps in, focus on the one thing they know is the cause. The strike zone: in major league baseball the strike zone has gotten smaller over time. Why? The de jure strike zone is slightly smaller--changed from the shoulder to the armpit. In fact, the de facto strike zone is really the waist to the nipples. Hayekian emergent phenomenon: umpires who did that made for more offense and people like offense generally. Did happen; home run hitting has increased. General evidence: is there a secular trend? Why? Underlying reason for my not believing steroids had nothing to do with it is that nothing has changed. Shrunken strike zone--from 545 square inches to 410, de jure--the distribution of home runs has not changed. A few draws from the underlying distribution, which has been stationary over a longer period of time. If you think home run hitting has increased, you have to make the argument that the distribution of home run hitting has somehow been shifted--upper tail been pushed out, bottom pulled upward; tilted the distribution, putting more mass on the high outcomes. Turns out not to be the case. Distribution virtually identical. Which measure are you using? If you look at number of players who hit 50 or more in a season, disproportionate share of those seasons are in the 1990s and later. Twice as many players, twice as many games. Seasons 1959-2004: if you plot the frequency distribution of home runs per player per 200 bats or more--semi-regulars and regulars. Why that instead of home runs per at bat? Home runs per at bat used; turns out that it has a very odd statistical distribution. Depends on strategy. Function of time during the game player is up, what his role is in terms of the outcome of the game, depends on what his manager tells him to do, and depends on walks, because a walk is not counted as an at-bat. If you do look at it, it hasn't changed. There are a few more at-bats now than before. Walks are down. A lot more strike-outs now. In view of the smaller strike zone and increase in number of strikeouts per at bat, you know that there's been a change in strategy. Presumably, the naive prediction would be that as the strike zone gets smaller, there should be fewer strike-outs; but a smaller strike zone means pitchers are more likely to pitch near your power sweet spots, and therefore you are going to swing harder. Elasticity question in economics, whether your incentives to swing harder offset the size of the strike zone. Ironic you get more strikeouts with the smaller strike zone. Clearly indicates a change in strategy. Per game. Some adjustment in the number of walks. Measure of power, homeruns per hit. Not the only way to look at it; could look at slugging percentages. Homeruns per strikeout: older players more efficient at homeruns per strikeout.
23:06Also have the effect of the newer stadiums tending to be smaller. Bottom line: For the bottom 4/5 of the distribution, there's zero change, totally flat. Bottom 80% of the talent shows no improvement over time in ability to hit home runs. All in the top 20%; and that's very person specific. More extreme than that. From 90% down there's been essentially no change. Take each of those percentiles, plot them, essentially flat. Only peaks occur amongst these truly exceptional hitters. Temporary peak in 1998, 1999, 2001; otherwise it's flat, too. A little below now what it was in 1965 and the mid-1970s. Curious slight decline in home run hitting through the late 1970s and 1990s. Then there was a little peak, late 1980s, pretty much back to normal, where it was in 1960. Have all the percentiles, exception above, influenced by a few extraordinary people. Before leaving baseball: you played with Dick Stuart, minor league career with the Pittsburgh Pirates, correct? Same system? Spring training together, Hollywood Stars, first baseman--got the name "Doctor Strangeglove", ended up on the Red Sox. Hit the ball a towering distance.
26:00Evolutionary fitness, followed on blog; scared Russ's wife, dead deer draped over his shoulders--goal. What is evolutionary fitness and what are you doing with it? De Vany sitting here in his 70s, weighing what he used to weigh. Book coming out in the United States and United Kingdom detailing the approach. Peaceful way to live. Your genes encode a smart, physically active, highly adaptive hunter/gatherer, the profession of all humans but for the last 10,000 years ago when farming began. Jared Diamond and others call farming the worst invention of mankind. We know that human stature declined; health declined precipitously; brain volume shrunk; many infectious diseases invaded because of close proximity and poor sanitation. Have lived for the last 25 years as if a 21st century cave man, hunter-gatherer; follow a diet that is primarily a modern enjoyable diet, but predicated on the fact that many foods now introduced did not have a role to play in the evolution of human metabolism. Do not eat any grain or grain-derived products. They entered the human diet only as early as 11,000-13,000 years ago, in some areas. For North American Indians, only a couple thousand years old in their diet. Avoid grains, avoid milk; outgrow need for milk, at the age of three, all hunter/gatherer children tend to be weaned, no longer on the mother's milk. Until food restrictions in northern climates, no longer drank milk of some other animal. A little calf has a lot of growing to do. Milk has a lot of insulin-like growth factor in it, which causes insulin resistance. Insulin resistance in a human being is somewhat troubling to our metabolism, not to mention the foreign proteins in milk. As an economist, we have to realize that evolution is a very conservative process; there have been very minor changes in the human genome since the first fully modern humans emerged about 100,000 years ago. Our paleolithic Cro-Magnon ancestors of 28,000 years ago have had their DNA sequenced now, and virtually identical to that of a modern human. So our genes haven't changed, but our diets and activities have changed. Eat wonderful delicious fresh fruits, lean meats, seafood. The Paleolithic was a very cold period; humans were forced to the shoreline about 50,000 years ago, at the height of the last glaciation, actually got worse about 17,000 years ago. Rapid expansion of human brain that took place during that period was, one, probably engendered or assisted by need to survive that brutal ice age; and two, by the seashore-based foods that occurred because we were forced to the shorelines for protection to the cold.
31:12How do you answer the fact that paleolithic man didn't live very long, and modern, grain-eating man lives for a long time? Life expectancies are at a maximum. Some due to medical technology; some due to more calories during childhood and infancy. Why revert to more primitive diet? Beautiful story, but what's the evidence--other than the fact that you look great for 72 and I look pretty lousy for 55? Thanks very much. One of the great advantages of radio or podcasts is you can say you weigh the same as 60 years ago; I could say the same thing. But I not born 60 years ago, so not tenable claim. Small set of data. What would you do to encourage this? What evidence? Infant mortality is a determinant of life expectancy. We have been removed from pathogens and food shortages and the dangers of paleolithic life. Like lab rats. They lived three times longer than wildlife, wild rats; and we live roughly two and a half times longer than our Paleolithic ancestors did, because we are protected and safe. But we suffer a variety of diseases that they are completely free of. When Albert Schweitzer went to Africa to treat the indigenous population, he was amazed at their relative freedom from disease. Saw no colitis, no inflammation, cancer; can't find a depressed hunter-gatherer, a psychiatrist. Probably a good deal smarter than we are because human brain sizes have continued to shrink. We no longer have to have those tremendous cognitive skills to stay alive in a very complex world with scarce nutrients. Yet IQ seems to be rising--or at least that's the claim. Of course we are all better at testing now. IQ testing is so problematic anyway. You and I wouldn't survive half a week in a Paleolithic environment. But we could live there the tribe would take us in and teach us how to move around and we would be much healthier than we are. Aboriginals in Australia come into the city and get sick; go back into the bush and get well again. This has been done experimentally. Foods, activities all alter gene expression. Our genes come from a different time. In terms of longevity, once the hunter-gatherer has survived to adulthood, their probability of death is no higher, but for some slight difference due to accident or starvation, than ours are. Well known that when Europeans live side-by-side with hunter-gatherers--they farm and hunter-gatherers are hunting and gathering--they live less long.
35:21Turn to exercise. Big critic of jogging and marathoning. Empirical data impression: effects are quite small. Is that because we are doing the wrong kind? Misreading the evidence? Evidence is not so much for exercise, because most people do such unproductive exercise. The way they count exercise very difficult. You have to pass a threshold of intensity or exercise does very little good. Not about burning calories; it's about altering your muscle mass and changing your hormone drives. Study by Ruiz, Cooper clinic patients over long period of time, ranking incidence of cancer: the people who had the lowest incidence of cancer death were the strongest; and the next lowest down the line. Stair-step function. If you look at people who survived to be centenarians or older, they have two common characteristics--true all over the world. One, they are very strong for their age--which means they are very lean and muscular--and two, they have very low insulin. Insulin is the aging hormone: nutrition is abundant and it's time to reproduce; turns on genes that are geared toward reproduction and turns off genes that are geared toward stress-resistance and repair and maintenance. Knowing economics has helped me enormously to think through some of these issues. Suppose you are a hunter-gatherer in the Paleolithic era; suppose you are on the African savannah. Nutrient: simple carbohydrate. When would it be available? If you came upon a wild honeybee hive--and hunter-gatherers went to great risk to get honey. African bees--this is scary! Or if you come upon a tuber out of the ground--and tubers were not readily available. Occasional seasonal fruit, springtime. What the hunter gets the rest of the year are simple, delicious dark colors, lots of glucose and fructose--signals of nutritional abundance. A young man's thoughts turn to reproduction. It all fits. Glucose would have been the least abundant nutrient and therefore would have been the most powerful signal to the genes to turn on reproduction and turn on repair and maintenance. Your genes know if you reproduce, then they don't have to take such care of you. Disposable soma. Almost every element of economics. Tradeoffs. Genes say they can jump ship. The people who try to do caloric restriction are trying to turn down the insulin IGF pathway--growth and reproduction. Claim: If I eat very little I will live long. What do you think of that? Think it's bogus. Cause a miserable life. Spoke to their society; some admit to being cancer-? [sp.?] or to cheat. When the mind is occupied with getting the glucose it needs, it turns to devious methods. In starvation experiments, people who self-mutilate, they cheat and lie and steal and do all sorts of bad things. It's a very stressful way to live. But using our economics, if we think back about glucose, turning on the genes to promote either life extension or reproduction, all we have to do is restrict glucose and we get the same benefits. The same benefits meaning more maintenance? Centenarians long and lean? Your claim is they have less glucose in their diet. Some have prodigious amount of fat; but that's beside the point. Universally they test for low insulin. Why would you have low insulin? Because you are not ingesting simple carbohydrates.
41:26Fitness: What's wrong with jogging? Economics again. Jogging uses slow-twitch muscle fibers. Not getting above any particular threshold of intensity. A hunter-gatherer--in fact, people have done this, do jogging with hunter-gatherers who say, Are you crazy? Why would you ever do that? Useless activity, doesn't build muscle mass, wasting energy. Our genes and brains tell us there are two threats to our survival: an inability to move rapidly and the lack of glucose for the brain. We are evolved to be lazy over-eaters. Energy conservation strategy that kept our ancestors alive. Goes against the human grain to jog. I can't jog; I've tried it, it's impossible to do. If you jog you use only your slow-twitch muscle fibers. Body says, I don't need these fast-twitch fibers; I'm going to shed muscle mass. Turns out that joggers on average are fatter than other athletes. Fatter, meaning less muscle mass and more fat mass, ratio. Body sheds the skeletal and muscle mass because it gets in the way of being able to jog efficiently. As an economist: law of unintended consequences, market forces working against you in any complex system. Example: if you think you can lose weight by skipping breakfast and lunch you are going to be sorely disappointed. Things that seem obviously effective in weight management don't always turn out that way; they set in motion these other forces coursing through the complex system of your body. Top-down, command and control diet systems do not work. If you are listening while you are jogging: maybe you shouldn't take this to heart. If you start doing the fast-twitch stuff, it's shorter, maybe you are not going to pay attention; some EconTalk listeners listen while jogging, but we'll take a chance! Defenders of jogging also claim it's good for your heart. Threshold of exertion. Claim is that steady exercise, steady exertion builds your heart. Worry: how do you know it doesn't wear your heart out? What exercise do you recommend and why? The human heart beats according to a random interval between beats, not a metronome. If you train to chaos, the heartbeat is actually chaotic. Fractal physiology--looking at fractal dynamics. Very sort of thing as I did in baseball, same type of power log statistical distribution that you find in home run hitting that you find in the human heartbeat. Human heartbeat somewhat chaotic--a lot of different controllers acting on it simultaneously; it's a lot of feedback loops and controllers affecting it. Fractal heartbeat is a sign of an adaptive, complex dynamics within the heart; makes it resistant to shock and to stress. If you jog excessively, you train the chaos out of your heartbeat--it becomes a metronome. The two forms of death from heart failure are, one, too little chaos in the heart, and two, too much randomness--not chaos but white noise. Want to stay away from both of those. Stay away from the way an animal or child does: follow a fractal variation in your activities as well, meaning a few easy, languid periods, a few bursts, including some very intense ones, in which case the average is meaningless. The average is nowhere near the mode of the distribution. So that's how I exercise; and how I work. How a lot of us work! If not careful, the languid part gets to be too much.
46:57Talk a little practically about your exercise routine. Weight training, exertion, jog work, treadmill, what do you recommend practically for people to do to replicate that hunter-gatherer exercise? Could play with your children or your dog. Most people are not prepared to do that. Add a playful sprint every time you take a walk. Spring up the hills. At UCLA, walk, spring up some hills, walks some more, spring up some hills. Intermittent. Varying what you doing. Exceeding the threshold, if you sprint large, and then walking and taking it easy. Enormously relaxing. A few moments of intense exercise equals hours of intense work. Changes your insulin sensitivity, changes your stress hormones, variety of other aspects. If you were to take a half an hour, would you want to walk 20 minutes and sprint 10, or 15-15, or does it matter? How would you you know if you are doing anything good or not? You will feel it. The joy you will get from the sprinting is quite addicting. If you treat it as play instead of as dreadful exercise you will have a whole different attitude about it. You will see the effects immediately. Go to a track meet: which body would you rather have? Distance runner versus versus sprinter. But for sprinter--10 seconds, of course they are happy. The other guy labored for 2 hours. But the sprinter is burning energy for 4-5 hours after the sprint--at a prodigious rate. You don't have to be doing something to benefit. The post-exercise period from a high-intensity session lasts for many hours, during which your body consumes huge amounts of fatty acids.
50:36Challenges of interpreting data and confirmation bias, charlatanism; fan of Ed Leamer. Is our scientific knowledge reliable? prone to the same problems? well known? are we making progress? Only about half of medical studies every replicate. Sure the replication rate in economics even worse. Based on that, serious problems. Meta-studies, lumping several studies together. Frightful. Some very bad conclusions coming out of that. All that really matters is continual testing and rejecting. Economics is not very good at rejecting; always looking for confirmation of theories. A good deal of that in the diet and health research too; for example, most of the early laboratory work on exercise was done with aerobics exercise because that was done in the lab. You can't do anaerobic or intense exercise very well that way because the body never hits a steady state. Models far more difficult. Bias toward aerobic exercise simply because that's where the light is: the drunkard problem. In terms of diet studies, similarly: neglect of the damaging role of anti-nutrients contained in grains and a bias against fat and in favor of carbohydrate; when just on an evolutionary record clearly contravenes anything that would have pertained in an evolutionary environment. The longer stretch of evolution helps to give you a wider sample to examine these things. They use a lot of p statistics and t-values and so forth--and very few medical statistics are normally distributed; and they always throw off the outliers. Economists, even embedded into some programs, they throw out the outliers. Homerun paper; in life, in health and physiology, the outliers exert the massive effect; unique, life-changing, economy-changing events.
54:06Practical question: habit formation, application and knowledge. Russ: age 55, ran a marathon around at 27 or so, unhealthy marathon, extremely steady 10-minute per mile pace, so a 4 hr. and 20 min. performance; very exhilarating though couldn't walk stairs very comfortably for about a week. Another aspect of jogging, damaging to joints; but since then exercise fallen slowly. Tend to do hiking in the summer, out of shape; diet way too sugared and carbohydrated; have trouble staying away from potato chips. What practical advice on diet and exercise that I'd have a chance of actually following rather than just dreaming about? This is the classic problem. You get the cravings because your insulin remains high. It's driven high by your diet and lack of activity. You should test your insulin. Most doctors won't do it, but I bet it's in the range of 9-12. What does that mean? It means its chronically high. If it's chronically high, remember how doctors killed their wives, or rogue nurses killed people--they injected excess amounts of insulin into them. What happens is they get brain damage. If you have high insulin and the insulin is being siphoned off into fat and muscle and organ tissues, the brain doesn't get it. Insulin is so powerful it can kill your brain because it can withhold the glucose that's in your blood stream. You have to get your insulin down. The cravings are your brain striving to get the glucose. Insulin resistance is nothing more than your brain trying to deny nutrients to your other tissues to reserve it for itself. Simply an allocation problem between your brain and the rest of your body. Most of the carbohydrates that you eat enter your fat cells because you are not draining the glycogen from your muscle cells. Competition between your selfish brain and your greedy fat. Get a big plate of pasta and want seconds! Insulin shooting up in response to the blood sugar; blood sugar crashes even though big dose. Chinese meal syndrome. Tug of war between your brain and your fat. Master hormone that regulates that is insulin. Not your energy expenditure versus your energy intake. Not what you eat or what your metabolism does with what you eat. Your metabolism is being directed overly much by insulin, master hormone. What to do? You want your exercise to be productive, not take a lot of time, and be fun. Easiest way to do that is to do some intense weight lifting. Rehabilitate heart patients with weight lifting, not jogging. Jogging is too dangerous. Suggest you work out no more than twice a week, 15-20 minutes each time; start each workout with a little brief sprint on the stationary bicycle; get in there and build some muscle mass, will consume glucose voraciously and increase insulin sensitivity and will burn fat like crazy. I burn way more fat than most people because I have a fair amount of muscle mass at this age. On eating, dead simple; but will take a month for your brain to adjust to the new diet. During that time, you might take a little magnesium and a little salt--healthful. Forage the outer perimeter of your supermarket, where all the produce, fruit, meat, and seafood are located. The cereal section is the most dangerous row in your supermarket. Don't eat cereal, don't eat milk; eat leftover dinners for breakfast.
1:00:24When cutting out carbohydrates in the past, hard to maintain that. Is that because of not exercising or because of not waiting a month? Both. Takes both together. Have to be kind to your brain in this time. A brain that lacks glucose thinks it's dying. It doesn't know it's in the 21st century. It will say Eat, and eat fat and sugar and do it now. Then you'll have to do it all over again; you'll get the same insulin rebound. You have to go cold turkey--is that correct? Easy turkey: supplement with fruit. Your ancestors starved; your brain is going through its primitive regions. You have to tell it you are not going to starve. If you exercise it will feed your brain in another way. You release lactic acid from the burn and working out. Ketones and lactic acid. You are supplementing instead of stealing from your brain. Variety of activities. Recommend: Skip dinner once a week, go to bed hungry. Run around with a deer carcass. Getting chased by a saber-tooth tiger. What about runners' high--long jogging? Good chemical that makes them happy? Also creates chemicals that cause brain cancer. Releasing endorphins. Some people can become partially addicted to it. High exercise does the same thing--brain neurotrophic factor, which also heals the brain, every bit as much of a high. Sprinters smiling. Stimulation beneficial to the brain. Opiate, opulate high, addicting to some; more addicting high intensity workout. Hormones without destroying muscle mass. Top ten reasons not to run marathons. Jogging different but totally useless. Maybe revisit movies some other time.

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COMMENTS (89 to date)
Floccina writes:

On nutrition and exercise I do not think that we know much beyond the basics.

And by the basics I mean:

We need to consume a minimum of each of the 12 amino acids.
We need to consume a minimum of certain vitamins and minerals.

Some minimum level of exercise is needed to keep muscles from atrophy.


Maybe I am biased because I love bread, pasta and pastry (I just had my favorite pastry over the week end, sfogiatelle they are so good they are guaranteed to get you to break you low carb diet).

BTW I am 6'5" and 204 lbs and I love my carbs.

John Giagnorio writes:

Thanks for this one, Russ. I've been waiting for some time to hear Art De Vany on Econ Talk. Does this mean the end of hearing you say "We all know you need to eat less and exercise more"? :)

Rob L. writes:

Right after I ate my cereal I listened to this podcast on the treadmill.

arnold writes:

"That there is any such thing as performance-enhancing drugs is largely a myth, not supported by any strong evidence"

"To build upper body mass, steroids are not really proven to be effective at that; the increase in lean body mass that does sometimes result from a combination of hard training and steroids is primarily slow twitch muscle fiber, not the fast muscle fibers that impart strength and quickness to an athlete."

Sorry, this guy is just an academic pin head. I invite him to investigate the differences between "natural" bodybuilding and powerlifting competitions, which have strict drug testing, and the less regulated competitions. Alternatively, he could look into Ben Johnson's 100m PR while on steroids and without steroids. Without, he was just an average elite sprinter. On steroids he destroyed Carl Lewis and set a world record that would have lasted almost 20 years. We have good before, during, and after steroid usage data on Ben.

Amazing that your guest claims there is not enough data to support efficacy of steroids, but then embraces a very speculative (possibly correct, but nevertheless with much weaker support than the steroid hypothesis) diet theory.

arnold writes:

PS If you believe in market efficiency you should believe that professional athletes and trainers know enough about steroids to decide whether they are worth the substantial risks (legal and health wise) and effort they entail. Why aren't these actors rational and well-informed? Why do we need drug testing if steroids don't work?

emerich writes:

I have no special expertise to evaluate deVaney's diet and exercise claims, but I can comment on his teaching. I lived in Houston for three years in the early 80's and happened to take an economics course with DeVaney, who was a visiting prof at the University of Houston. It was an electric experience. His lectures were full of arresting but unassailably logical claims and assertions, and always great fun. Lost track of him so it's great to find him still knocking out insights as entertainingly and persuasively as ever.

Trent Whitney writes:

While I enjoyed the podcast, I have a few problems with Prof. De Vany's analysis regarding steroids and home run production.

First, in the early part of the podcast, I believe his point is that you cannot tie steroids to increased home run production "because of all the failures." In other words, because there were so many players who presumably took steroids and did not hit 50+ home runs in a season, there cannot be a tie.

Having read both of Nassim Taleb's books recently (both are fantastic - and he does mention Prof. De Vany favorably, by the way), I'm becoming much more sensitive to logical fallacies. Simply because all the players who hit 50+ home runs in a season (of late) took steroids, does not imply that all players who took steroids should hit 50+ home runs in a season.

In fact, I believe Prof. De Vany's later statements actually comply with the "inside baseball" argument that ties steroids to increased home run production. That argument is pretty simple - that sluggers who already have great home run power (Barry Bonds, Mark McGwire, Sammy Sosa) would hit a few more home runs because their warning track fly balls (those long fly balls that are just short of becoming home runs) would carry marginally further. And you'd have the occasional players who possess warning track power (Brady Anderson, Ken Caminiti) who would break through with a strong season every now and then.

Prof. De Vany speaks to how the upper group of sluggers all saw home run increases, while the rest of the players didn't, save a few outliers like Brady Anderson. Those findings correspond to the above argument. It should be rarer for the warning track power guys taking steroids to break through....but it should happen once or twice a season, and hence they look like outliers.

As to Prof. De Vany's statistics showing how the home runs for the bottom 90% is essentially flat, there is another interesting trend that needs to be taken into account, and that is that many pitchers have taken steroids, too. That brings us into the "does good pitching beat good hitting or vice versa" argument.

Suppose, for some reason, that pitchers on steroids are more dominant against batters, except for those sluggers who are taking steroids, too. Wouldn't that lead to the outcome that he found?

Also, what about the case of Frank Thomas, who professes that he never took steroids? In his prime, Thomas posted great batting averages, low strikeout rates, and had tremendous power. Yet without steroids, he never posted one of those 60+ home run seasons that the steroid users did. You could argue that Thomas wasn't as talented as the other players in the areas that Prof. De Vany mentions, but to anyone who saw Thomas play in his prime, I think they could argue differently.

Prof. De Vany didn't touch the subject of why these sluggers took steroids in the first place. If it truly didn't help them, why did they take them, and why did they keep taking them?

Lastly, I'll refer to a subject I wrote about at Cafe Hayek again because Prof. De Vany mentions Roger Maris in this podcast and how his 61 home run season was an outlier a la Brady Anderson. I'm sure he knows that steroids were first used in sports in the mid 1950s, and there's a new school of thought concerning Maris because he fits the profile of a steroid user: Warning track power guy who has one huge breakout season, breaks out in acne, loses hair (I know that's rebutted in the broadcast per Brady Anderson), retires early because his body breaks down, and dies young due to heart problems. Suppose just for the sake of supposing that Maris was indeed part of this steroid group - would that change Prof. De Vany's findings?

I apologize if anyone finds my writing too long. As Russ knows, I worked for a MLB team for four seasons, so this is a huge area of interest for me.

skeptic writes:

DeVaney says powerlifting uses slow twitch muscles, which is completely wrong. Marathoners, who have a lot of slow twitch fibers, have good endurance but are slow and weak. Powerlifters are unusually quick for their size and would have very good power numbers, such as in vertical leap, 40 yd dash, etc. There is no doubt that steroids aid performance in power and olympic lifting. BTW, he seems not to be aware of Soviet and East German sports programs for female sprinters that relied heavily on steroids and allowed them to outperform for many years.

I can believe his claim about steroids and baseball; at least, the evidence is murky. But it's obvious he knows next to nothing about steroids and athletic performance in general. Ironically, he is overconfident about what knowledge he has.

Neal W. writes:

I've followed De Vany for years and read his original paper on steroids and baseball a few years ago.

I just don't understand his claim that steroids don't build size though. Steroids have been shown to build size without even exercising. Also, small doses can allow you to keep size down, so you don't blow up like a professional body builder, and enhance recovery so that you can train more often.

However, it can still be true that steroids have not increased home runs.

David writes:

I found Professor DeVany very interesting. His theory on diet sounds a lot like that of Michael Pollan, which boils down to a few simple rules: (1) eat food; (2) not too much; (3) mostly plants; and (4) stay away from anything that your grandmother wouldn't recognize. Pollan, like DeVany, suggests that you should shop the perimeters of the grocery store and avoid all the processed food on the cereal aisle. He is fairly critical of nutrition science, arguing that we really don't know enough about it to draw any firm conclusions. I wonder what Professor DeVany thinks of Michael Pollan's arguments? Also, solely from personal experience, I tend to agree with DeVany's theory on exercise. I've always exercised, but have by and large quit jogging, the treadmill, and similar activities. Exercising everyday for short, but intense periods of time, seems to agree with me much more than longer, less intense exercise. A short nap during the day seems very beneficial as well. As I listened to DeVany, I thought that my routine (with no planning on my part) mimics the hunter-gatherer life style -- a lot of "hanging out" punctuated with short bursts of intense activity. But, perhaps that is just my own confirmation bias!

bdubs writes:

@skeptic--Remember, Evolutionary Fitness is not simply some academic theory. If you actually go on his website, you'll find that he's selling a bunch of DVD's, and you can't access the full text of his blog entries unless you pay for a yearly subscription. So, he most certainly has a horse in this race. I found it entertaining to listen to him, but was disappointed that there wasn't better disclosure of this monetary interest. While listening to the podcast (and before I went to his website), I did have the feeling that the part on Evolutionary Fitness felt too much like an infomercial. I'm disappointed.

arc of a diver writes:

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buddyw writes:

I found the episode interesting. I might even try evolutionary fitness/paleo diet rout in the not too distant future and had not heard of it before yesterday.

The science is not 100%, but there have been some recent studies that show some positive effects of a low carb diet.

I have no problem with a guy making money off of a message like this. I would be paying him for his research. It just means I need to find some independent claims that prove he isn't just blowing smoke.

From what I have read, his previous wife died from complications of diabetes, and this has fueled his lifelong research on nutrition.

As far as baseball and steroids, I found the conversation very interesting. I don't really know that much about steroids, but he make good points.

interesting reading:
http://women.timesonline.co.uk/tol/life_and_style/women/diet_and_fitness/article4523487.ece

So I'm an avid listener and occasional commenter here at econtalk and also over at Cafe Hayek. I'm not an economist yet I enjoy learning more about the subject, always like a good argument, and often walk away relatively satisfied

But I am a biologist, and I can't tell you how disheartening it is to listen to a program which I take so much joy in and where I learn about topics that I know little about, only to hear someone come on and butcher the topic that I do know a lot about. It makes me question far more of what I'm hearing, which I suppose is a good thing but not if it makes me question to the point of my listening becoming a useless endeavor.

One claim made was that brain volume has shrunken which shows how bad agriculture has been for us. Come on now, we all know the next question to ask: has there ever been an even moderately significant trend between cranial volume and intelligence in humans? Not even close. Indeed our Neandertal 'cousins' had larger cranial volumes than modern man, but so do elephants. It frankly says absolutely nothing.

Let's talk more about butchering theories of evolution. We're told that evolution is a conservative process and genes haven't changed hardly at all in 28,000 years. Then five minutes later we're told that compared to hunter-gatherers "We no longer have to have those tremendous cognitive skills to stay alive in a very complex world with scarce nutrients." We're devolving ourself rather quickly but lack the ability to evolve; bonk.

The thought of homo sapiens, or any of the homo/austropithecine lineage, evolving in seaside environments is again, absolutely false. Virtually all theories of human evolution are predicated on the move from forest to grassland environments. No humans were probably sea-faring for any period longer than 30,000 years ago so how we would have the ability to catch and eat seafood aside from the relatively small percentage of small shore-dwelling fish is beyond me. Clearly climatic changes placed serious pressures on ancient populations to move, and surely some of them included a move to bodies of water where fish may have been a staple. Whether this lasted for a period long enough to create an evolutionary pressure for the ability to properly digest fish more than grains is complete pseudo-science.

If we weren't 'meant' to eat grains, how do we explain other things which we most certainly never ate prior to the modern age: namely anything that you'll find in the supermarket (even on the outside). But somehow what we now call a chicken/pig/cow is better for you than potatoes even though we most certainly never encountered anything bearing more than a passing resemblance to a modern pig during our evolutionary history?

How about the claim that humans weren't meant to drink milk. This rebuttal is even coming from a vegan who doesn't drink milk, but it is absolutely known that lactose tolerance has evolved at least 3 separate times in human history: twice in africa and once in northern europe. Why did it evolve? Because those who retained the ability to drink milk survived in greater numbers than those who didn't. Most of us here in the U.S. are descendants of one of those populations and we retain production of lactase (the relevant enzyme) through adulthood, while other populations (notably asians and much of africa) don't. Who is more human? It's an absolutely outrageous claim that we 'naturally' shouldn't drink milk based on this crap evolutionary explanation.

I'm glad you at least mentioned runners high. I was squirming in my seat hearing how great sprinters feel and how terrible distance runners do; it's absolutely not true. I'm not familiar with the all the mechanisms but those darned brain cancer causing endorphins that cause runners high also show up in other evolutionary detrimental practices such as feeling love. sarcasm should be evident.

i'm not going to go through everything i heard that is complete nonsense, nor am I claiming to not agree with certain issues (I.e. interval training is clearly the best option if you want to exercise). but once i find as many fallacies as I did during this conversation, finding a few statements that I agree with is a poor and statistically insignificant consolation prize.

however, one bit of kudos towards dispelling the myth that older populations had a shorter life-span; as was mentioned this comes from high infant mortality rates that drag down the average. If you look at average age of survival for those living past 20 for example we have no reason to believe maximum life span has changed greatly anytime in the past 100,000 years or across current populations however the prevalence of more accidents even through adulthood will continue to drag this number down in certain populations.

skeptic writes:

"...it is absolutely known that lactose tolerance has evolved at least 3 separate times in human history: twice in africa and once in northern europe. Why did it evolve? Because those who retained the ability to drink milk survived in greater numbers than those who didn't."

This is correct, and I strongly suspect that humans also evolved adaptations to allow them to better digest grains and rice. It is a common misconception that 5-10k years is not enough time for genetic adaptation. It's all a question of selection pressure and we have examples like lactose tolerance that show that agriculture impacted human evolution.

DeVaney's understanding of evolution is very poor. I'm not saying his general thesis is wrong (I actually follow, to some degree, both the paleo exercise and diet recommendations), but the logic and facts used to support it are indeed poor -- nothing more than an evolutionary "just so" story.

The most disturbing thing is the degree of certainty he expresses for what must, honestly, be described as speculative hypotheses. Is this part of the training in economics? At one point he did say something refreshing, to the effect that economics is unable to falsify models. I'm not sure how hard DeVaney is working to falsify his dietary and fitness models.

The merits (?) of endurance running:

Bramble DM & Lieberman DE. Endurance Running and the Evolution of Homo. Nature. 432:345-352. 2004.

http://www.nature.com/nature/journal/v432/n7015/full/nature03052.html

I'm absolutely not saying that all their arguments are flawless in this regards or that all Professor De Vany's are flawed. But as the last commenter mentioned, presenting his thesis against distance running as some sort of scientifically accepted truth is irresponsible, detrimental to his own thesis, and drags the value of this podcast away from critical discussion and a bit closer to a bully pulpit.

Mort Dubois writes:

"There are no performance enhancing drugs". Uh, no. EPO works very well, as a generation of professional cyclists will tell you. With an absolute whopper like this in the first minutes of the podcast, it's hard to take the rest seriously. Entertaining, yes. Rigorous, probably not.

Mort

John S. writes:

I was struck by the contrast between the first half and the second half of the interview. In the first half Devaney came off as an analytical thinker, a skeptic unswayed by the conventional wisdom or the existence of outliers such as Sosa and McGwire. His motto seemed to be "show me the data". And even though I'm not sure I agree with his conclusions, at least his conclusions are based on analysis of data.

On the other hand, in the second part of the interview he pretty much admitted that his thinking on diet and evolution was not based on hard evidence at all. He claims that his dietary and exercise recommendations are based on evolution, but to me they seemed like ad hoc inventions made to confirm his particular prejudices. He believes his theories because they works for him. Yet he himself -- as a septuagenarian with a bodybuilder's physique -- is as much of an outlier as Sosa or McGwire.

Terry writes:

Once again, someone mentions steroids and baseball and only focuses on homeruns (or power).

Cyclists don't use steroids for power, they use it to recover from riding 100 miles the previous day. (There are other substances for power.) Andy Pettitte didn't want power, he said he used it "once" to recover from an injury. Mark McGuire didn't start regularly using steroids until the 1993 season when he had so many frequent trips to the disabled list that he tried it. (This was in a Times article after McGuire "came out".) It is not a coincidence that the first year of testing with suspensions, Barry Bonds gets a knee injury and doesn't play most of the season. It is not all about the long ball.

Mark M. writes:

I agree with John S. - the baseball/steriods discussion seemed very analytical, but the discussion of evolution/fitness seemed to be shooting from the hip.

The latter discussion reminded me of an article in the NYT from Oct. 2009 that seems to contradict his claims about running. Here's a key excerpt:

"The scientific evidence supports the notion that humans evolved to be runners. In a 2007 paper in the journal Sports Medicine, Daniel E. Lieberman, a Harvard evolutionary biologist, and Dennis M. Bramble, a biologist at the University of Utah, wrote that several characteristics unique to humans suggested endurance running played an important role in our evolution.

Most mammals can sprint faster than humans — having four legs gives them the advantage. But when it comes to long distances, humans can outrun almost any animal. Because we cool by sweating rather than panting, we can stay cool at speeds and distances that would overheat other animals. On a hot day, the two scientists wrote, a human could even outrun a horse in a 26.2-mile marathon.

Why would evolution favor the distance runner? The prevailing theory is that endurance running allowed primitive humans to incorporate meat into their diet. They may have watched the sky for scavenging birds and then run long distances to reach a fresh kill and steal the meat from whatever animal was there first."
http://www.nytimes.com/2009/10/27/health/27well.html?_r=1&pagewanted=print

Jake Russ writes:

I haven't quite figured it out, yet, but De Vany's choice of HR stat to look at bugs me. It could just be nothing, maybe someone else will help.

He is using HR/Hit. Rephrased, given a plate appearance results in a hit, what percentage of those were HRs?

I think a more straightforward thing to test would be (HR/Balls in play + HRs) or [HR/(AB-K+SF)] I realize this is loose terminology but since just "balls in play" would take out the HRs in the denominator you have to add that back in.

The reason I say this, a batter's batting average on balls in play (BABIP) will fluctuate due to luck. (Google "batter BABIP" for more info) So the use of that stat could mask the true effect by having the hits component intertwined with year to year luck.

What I think you'd want instead, is given that the batter made contact and put the ball "in play", what percentage of those were HRs? If you see a spike there that would be less likely due to good/bad luck.

Is this a distinction without a difference?

Trevor writes:

When I put on mass from working out over the winter I hit the ball farther and more often in the spring.
But mainly because I can wait longer to get the bat around or stop the bat more easily mid-swing.

Never done roids so I can't comment on their affect on performance.

The nutrition points are interesting but the marathon points are a bit backwards. It's not just about running X miles and brain cancer, it's about diet, sleep, stress reduction, fresh air and a host of other things.

I took up running and biking and stopped drinking and smoking and I eat much better.

emerich writes:

Much of the argumentation above is on peripheral matters. We can debate the details, but it seems we all agree that we need to eat like our paleolithic ancestors.

Jeremy Coghlan writes:

Playing to my biases, I agreed with the exercise recommendations because it fits how I happen to like my exercise.

I enjoy cycling to work 1 or 2 times a week because its a combination of:
* uphills (hard sprint)
* flats (just cruising)
* downhills (tuck in and stop pedalling).

Heart rate goes up and down; feel great at the destination; metabolism keeps me physically warm for 4-5 hours afterwards (even in winter) and I build a little bit of muscle (mainly legs, however). Oh, and I sleep better.

The other days of the week I drive my car: Perfect.

John S. writes:

You're wrong emerich, I don't agree that we need to eat like our paleolithic ancestors. I think that's a pretty dumb idea.

emerich writes:

John S, I bow to your logic.

benghis writes:

There was one huge assumption left unsaid regarding steroids in baseball, namely that this guy thinks he knows more about athletic performance than legions of professional players and trainers with millions of dollars at stake.

I think player's shrunken testicles are proof enough that there is such a thing as performance enhancing drugs.

MarcS writes:

So the best form of activity is long periods of taking it easy interspersed with random short periods of intense exertion. Hmmm, that sounds like baseball!

Life really is baseball.

John S. writes:

emerich, you showed the superior logic in assuming that everyone agrees with you, so it is I that should bow down before you.

Ray Gardner writes:

Very good podcast.

I didn't know exactly who De Vany was before this though I knew of the name, but I enjoyed that immensely.

Steroids and baseball:
Confirmation bias alert! This is the exact same thing I've been telling everyone in my own sphere. I'm an ex-jock of the woulda-shoulda-coulda type that would have probably topped out at double A ball had I made some better decisions. I also worked as a personal trainer in my 20s and learned about a lot about steroids both academically and practically at the gym level. De Vany is spot on.

Personally I am in the paleo-diet camp, but I do believe that many of the caveman eaters are flawed in how far they take some of their opinions. Despite the large amounts of data we have on primitive man, it's far from concrete and settled, but many of their proclamations are presented as universal truths.

An overabundance of grains, simple carbs, etc are not good, but there is a balance that can be struck that the primitive eaters deny.

Russell writes:

Fantastic! Russ, I have been hoping Art would be a guest for months now and I want to thank you for inviting him on the show.

He did not disappoint! And I hope he does come to discuss fitness more and his movie research.

As an unapologetic devotee of the evolutionary fitness approach, I am equal parts dismayed and unsurprised by some of the comments above. This lifestyle requires a true paradigm shift in thinking and behavior that many have difficulty grasping and often find offensive. I write this with empathy, not to be condescending.

While I do not blindly follow every thing Art says/claims, I do believe very strongly in the principles he outlined. And the physical and emotional results have been spectacular!

I would strongly urge those who are skeptical to give EF a full trial for one month and see how you look and feel. I think you will be astonished. And you don't need to buy a book or join a web site - there are plenty of free resources on the web in the paelo/primal movement to guide your efforts over a month. Cheers!

Matthew writes:

Mr Roberts finally found an expert on PEDs to confirm his belief that PEDs have not had an impact on professional baseball. This is an opinion that I've heard issued on EconTalk at least one other time in the past, and it was supported by De Vany in a grand manner today.

Unfortunately, there are a legion of issues with the premise that "performance-enhancing drugs is largely a myth".

First, PEDs are not limited to steroids, just as the pharmaceutical industry isn't limited to Viagra.

The other issue not discussed today was the fact that PEDs are generally good for a small advantage, say, 3-5% increase in performance. To a spectator of sport that can be viewed out of hand as trivial. But when we're talking about elite level athletes, even 3% calculates into a winning edge when all things go well.

The other serious problem with the baseball debate is that we do not have willing and open participants in the outing of which PEDs specifically were used by the athletes discussed on todays podcast. We don't know this information, so De Vany is free to make conclusive and somewhat convincing arguments.

I'm all for personal choice - one should take what one chooses to take, but they must accept the consequences - but to suggest that PEDs have no impact on sport is reckless for many reasons.

Finally, if you'd like an avid athlete's experience with PEDs (read not just steroids), check out this article from Outside magazine's Stuart Stevens written in 2003 (which, in the universe of PEDs is like a decades ago; this stuff has evolved, and continues to evolve rapidly): http://outside.away.com/outside/bodywork/200311/200311_drug_test_1.html.

Brian writes:

I am heartened to see that several folks have a already pointed out the flawed logic, lack of evidence, and poor understanding of evolution, displayed by De Vany. I won't repeat what has already been pointed out, but want to add a couple comments. For what it's worth, I have a graduate degree in Evolutionary Biology and my wife is a Nutrition Specialist at a major teaching hospital and teaches both graduate and undergraduate Nutrition (interestingly, when I told her about De Vany's comments in this podcast, she immediately recognized many of the phrases he used and examples he gave as being used by authors of previous books. She said his arguments were quackery but he is going to make a lot of money on the gullibility and general ignorance of the mainstream population).

Okay, De Vany seems to think the only food humans farm are grains. News flash, fruits and vegetables have been farmed as well, and the nutrient content of today's fruits and vegetables is very different from those of paleo man. The fruits are bred for high sugar content, large size, pleasing appearance, pest resistance, and other qualities. While veggies are not bred specifically for high sugar content, they most definitely are not bred for high nutritional content either. Like fruits, they are bred for those qualities that will yield the highest net profit to growers. The point being that the fruits and veggies we eat today are not the fruits and veggies we ate as hunter-gatherers. Furthermore, most of the calories in fruit and veggies are carbohydrate, that nasty nutrient that De Vany wants us to avoid. Moreover, the fruit is predominately simple sugars, the nastiest of the carbohydrates (according to De Vany).

He mentioned "foreign proteins" in milk. So, we should avoid the foreign proteins in the cow's milk, but we can feast on the foreign proteins in the cow's flesh, as long as it is lean. Makes perfect sense.

What about nuts/seeds? No hunter-gatherer worthy of a cave would pass up a handful of those.

De Vany is worried about the alleged "anti-nutrients" (whatever the heck those are) in grains, and the alleged carcinogenic compounds produced by sustained aerobic exercise, but he is not concerned about the documented accumulation of known toxins in fish. Honestly, his analysis of the human diet is so flawed there is too much to cover in a comment here.

The notion that humans evolved to a diet of fish during the Paleolithic period is utterly preposterous. Not knowing much about steroid use or baseball, I accepted De Vany's arguments about steroids and home runs. However, after listening to his Evolutionary Fitness hypothesis (money-making scheme) and reading the comments here regarding steroids, I think the whole baseball hypothesis is probably bogus as well.

I do agree with De Vany on one thing, simply doing the same exercise over and over is a mistake. The more varied the exercise, the better (and the more enjoyable). I also agree most Americans eat too much carbohydrate, but carbohydrate is the preferred energy source of human cells. Aerobic respiration is the most efficient use of energy in cells, and efficient use of energy would be key for hunter-gatherers. Hunter-gatherers are opportunistic and will take food in whatever form available. Also, it was not uncommon for them to gorge themselves when they came into a surplus of food, even carbohydrate.

Gus writes:

I'm always struck by the similarities between diets and religion. Both have their true believers who are certain about everything, despite the lack of evidence. I think there is a deep connection there, since so many religions require their followers to eat a specific diet.

A recurring theme in a lot of religions is that things were better in the distant past. The ancients were in direct contact with God, and if we could just get back to worshiping like they did -- practicing that "Old Time Religion" -- we too could find salvation. Devaney's evolutionary fitness regimen seems like a dietary form of that same delusion.

Jim writes:

This guy is Cliff Claven with an economics degree.

I assume as a tenured professor, he does have some area of competence. I also assume that his area of competence is not what we were treated to.

What makes him the most irritating kind of academic, is that his knowledge of sociology, anthropology, physiology and evolutionary biology is about an inch deep. He's clearly an amateur and dabbler, and yet cloaks his amateurism it in an academic position in another field and vague references to 'the literature.'

By tuning my internal translator to convert "It's well known..." to "There is literature which might suggest..." I was able to finish listening.

(And on steroids, I've heard better arguments in bars. His intuitive argument is that a baseball swing is the functional equivalent of a golf swing -- that is it is more about precision, speed and technique than strength. No one believes that a golfer would add yards to his drives by building body mass, thus no one should believe that a baseball player would add distance to fly balls with extra body mass. But we know that baseball hitting is about all those other things and strength. Which is why basebal player took steroids and golfers didn't.

His statistical argument relies on a cherry-picked statistic, and any anomalies are waved off by invoking 'the modern swing' and 'the shrinking strike zone'.)

Sam Lundstrom writes:

I actually enjoyed this interview. But I also have absolutely NO clue on nutrition. And I've never been inspired in the least by the low-carb rantings of my friends. After listening to De Vany yesterday I went to Costco and bought a bag of walnuts and some veggies and I ate some pulled pork without the white bun:) So for the biological and nutritional laity such as myself, De Vany tells a good story that actually motivated me to ditch the potato chips for an evening. That's more than I can say for some experts I have listened to. And I think Russ kind of falls into my camp. So those of you who have commented on this board who are 'experts' in the field, maybe this podcast will inspire you to not overlook the persuasive power of a good story to go along with all of your data:)

On the other hand, ya better be careful about interviewing academics about fields that are outside of their expertise in the future Russ. Based on some of the comments here it appears you are facing something of a mutiny from some previously loyal listeners.

Nick writes:

He never answered the fundamental question his proposition about steroids raises. If steroids do not enhance performance why do players take them. Not only take them but pay high prices and risk their career over it.

Ray Gardner writes:

Outdoor magazine is an awful collection of marginal opinions and left wing ideologues. I received a gift subscription and was sadly disappointed.

I'm a very talented athlete who has experimented with steroids, and can tell anyone interested that they do give a slight edge for specific applications, but not for hitting a baseball - especially at that level. They take them for the same reason that most people think they work - ignorance.

They do of course put on some decent muscle mass, and the kinds they take are some of the better quality stuff, and not just the water retention D-bol kind of stuff from the 80s. So they tend to keep more of their muscle, while avoiding many of the pitfalls. (Testicular shrinkage for instance does not occur right away, and can be easily avoided if the cycle is done correctly.) So the placebo effect is astronomical. They put on 20 pounds of muscle, their nads actually grow a little, and they feel like they can walk through a mountain.

The problem with the diet is that it's largely based on the incomplete theory of when modern man developed farming. There is evidence, but we really don't know. Also, we really don't know if it was the advent of basic farming and the more readily available food supply that helped "primitive" man develop into the advanced man.

A better theory in my opinion would be to examine what the earliest farmers ate. Due to their well documented history, looking at what the ancient Jewish people ate would be a good start.

John writes:

A large part of our current diet is seeds, wheat, oats, beans, corn, peas, coffee, chocolate. The animals we eat are feed a diet of mostly seeds: corn and soybeans. It appears we do so because seeds keep so well. They will keep from harvest to harvest and fat times to lean times.

If everyone switched to De Vany's diet how would we grow enough calories for the year? Tomatoes won't keep more that a couple of weeks. Would we switch to root vegetables? Or would we figure some way to grow all our food in the south? What would happen to all the far northern farm land? Is it OK to eat meat that is fed mainly seeds? Or do we need to switch to grass fed? Grass fed has a whole host of problems to be able to feed everyone. Alas most supporters seem to want people in general to eat almost no meat. Isn't that a return to the bad old days where the rich had meat and the masses ate stale bread?

I'm not trying to "pick a fight" here, just wondering what some thoughts are, specifically from people like De Vany. Although we're getting off topic for an economics podcast.

Jean Parmesan writes:

I can go one better than De Vany.

I am on a strict Australopithecine diet of the finest berries, vegetables and tubers. It all went downhill when Homo Habilis started roaming around eating animals and what not.

(i.e. i did not find his arguments very convincing. 1/2 half of the podcast seemed to be nothing more than nostalgia bias)

Carl Jones writes:

I should probably comment on the multitude of podcasts that I really liked before commenting on this one, but I won't. This was pretty much completely uninformative.

He clearly had in mind that steroids do not enhance performance, then mined the data to find evidence for the conclusion he had already made. The important thing to look at would be the effect of steroids on the very best athletes, not the people who do steroids and are not the best, and not averages. These are irrelevant. Russ Roberts was clearly right that Barry Bonds and Mark McGwire got huge after using steroids. Bodybuilders and weight lifters know how well steroids work. And of course the evidence is going to be weak because experiments with high doses of steroids on humans are illegal. There are several studies published that give low doses of steroids and then use those results to say that they are ineffective. However, many of these papers still show significant gains even with these sub-McGwire doses of steroids.

And his diet is not supported by evidence. The claim that steroids help athletes is much stronger than the claim that a hunter-gatherer diet is the ideal for humans.

American Hero writes:

I know you don't get enough thanks for the podcasts. It's a weekly college class given to us for free by your efforts.

However, this podcast was about 70 percent exaggeration. Remember an earlier interview with the guy who said "we are a story telling, pattern seeking species?"

I tend to agree with the first part, there probably aren't any real "performance enhancing drugs" and you didn't touch on the issue of even if there was such a thing, why should I or anyone care?

The 2nd part was confusing. We like sugar because we evolved on the African plains where there was only the occasional honey bee hive? And "grains" are bad for us because we evolved on the coasts during an ice age and could only find fish and meat? Which is it? And we don't naturally eat "grains?" What if grains were growing out there naturally? What did a "hunter-gatherer" gather if not grains and fruits and edible things growing?

And don't even get me started on the biochemical pathways -- the brain doesn't "think it's dying" if we don't eat straight sugar like honey. All foods, carbohydrates, fats, proteins, are converted to glucose through various complex reactions that take place in the body. That is, the brain is always feed by a constant supply of glucose no matter what we eat. There are some nuances but this isn't biochemistry class.

And why don't we ever see a depressed hunter-gatherer? My guess is we see the bones of a formerly depressed hunter-gatherer bleaching in the sun. In other words, if a hunter-gather "gets depressed" and and really just isn't into the whole gathering or hunting scene anymore he probably dies. Now, we could do the same with our society with a machine gun, we could simply gun down anyone who said they were unhappy and I bet a visitor would say "wow, you never see a depressed American!"

p.s. (I really love the podcasts and don't take my criticism the wrong way)

Worf writes:

If primitive man in a state of nature were anything but nasty, brutish and short, why did they bother to invent agriculture in the first place?

Botswana writes:

Weren't hunter-gatherers walking long distances every day to gather and occasionally running short distances to hunt? Aren't we predisposed to walk a lot every day?

Mike writes:

bdubs, way back up at the top, mentions that De Vany charges a subscription for full access to his blog.

I was kind of intriqued by his dietary claims and went to the blog for more information. There is some free information, much more behind a pay wall.

Daily I am confronted with the dilemna of giving away information on the expertise I have developed over the years. I have to give some away to establish credibility with my potential customers. I also want to keep as much to myself because it is that hard earned information that allows me to make a living. It is a line that keeps moving around due to changing circumstances.

I didn't buy a subscription to the website.

De Vany's line ain't drawn in the right place for me.

Maybe I'll buy his book when I can get a used paperback.

I do think it was a great podcast. And I enjoy the fact that so many of the commenters disagree with De Vany. We come for the information, but Russ will have much greater success keeping us around if there is drama and controversy.

Jean-Marie writes:

Devaney's theories on diet and exercise would make a great subject for one of my other favorite podcasts, Brian Dunning's Skeptoid.

Chas writes:

I departed from my usual 5-mile jogging routine yesterday and instead walked and sprinted (not unlike the typical interval training). This morning I can barely walk because my muscles are so sore.

Mark Selden writes:

Can steroids enhance home-run hitting ability?

How about this for a theory:
Increased strength from steroids allows a player to more quickly get his bat up to speed, giving him more time to see the ball. I’ve heard many speak of the higher bat speed, but extra time to react seems at least as important, and probably more. The short time available to evaluate speed and trajectory, decide, and then swing at the ball has always been acknowledged as the greatest challenge to a hitter.

Just to rephrase: All things equal, players A and B both react "late" to a fastball. Player A fouls it off, stronger Player B gets around on it and hits it out (albeit to the short porch in right field).

Regarding De Vany’s assertion that steroids with hard training does nothing for fast-twitch muscles: Fine, but he is ignoring that there are exercises that DO develop fast twitch muscles; among them batting practice. Can he assert that those activities are not enhanced by steroids?

shawn writes:

@chas; not sure what you're trying to say--the fact that you trained your muscles differently caused pain, or that you have somehow disproven something?

In the event that you are going the 'disproving' route: I lift weights (not in a couple months, and my wife's on my butt about it, but that's beside the point). I can lift quite a bit of weight, more than probably 96% of the general population, and I do something that might be called "bouncing" at a local bar partly as a result of that. I can not, have never been able to, run long distances. Even in high school, when I weighed about 100 lbs less than I do now, I barely broke a 7 minute mile my senior year, after having tried and tried all semester to get my mile time down.

So, if I were to "run" even a 5k tomorrow (assuming I was in good physical weight-lifting shape), I'd be a nightmare 2 or 3 days from now. Your muscles get used to things that they're used to doing--switching that up and using muscle pain as an example of failed theory seems pretty darn flawed.

That said, maybe you were saying that you already run 5 miles regularly, and so you should be in great shape. But then, having done something different, you're really feeling the effects (I'm in grad school, and I still struggle with effect/affect...man, that's embarrassing), and so you're thinking that maybe your muscles aren't as trained as you thought they were. In that case, it seems to me that you're dead on...

So, either kudos or jeers, depending on your intention.

james gaulte writes:

My background is in pulmonary disease, internal medicine and exercise physiology and the cringe factor was very high for me listening to your recent podcast.Dr.De Vany either dismissed or is unaware of a large body of research that indicates that endurance exercise training decreases insulin resistance. That literature goes back at least 20 years and contains a number of different lines of research and techniques making that conclusion not only widely held but basically no longer an issue. One large clinical trial demonstrated that regular aerobic exercise decreased the onset of type 2 diabetes in subjects with multiple risk factors for diabetes and such exercise is a major element in most physician's recommendations for patients with type 2 diabetes.

Interestingly, more recently there are increasing data that indicate high intensity short burst type training also decreases insulin resistance.Many of the articles on that topic emphasize that the "HIT" training has effects that are similar to endurance training.I cannot believe that someone could put sweeping theories of diet exercise and health and be unaware of such a large body of data.
The stories he tells regarding how our hunter-gatherer ancestors behaved and should be copied are interesting but he ignored another interesting tale of how humans with their bipedal nature,lack of fur and capacity for long hunts (endurance exercise) were able to run down those animals who could out sprint them in hunts that lasted for many hours if not days.

His comment that there are no performance enhancing drug was followed by a comment that dehydration might help by raising the red blood cell concentration.If he believe that he should also believe that EPO which raises the hematocrit would also work.(Dehydration, of course, decreases exercise performance)

His comment that cardiac rehab program do not use aerobic training but emphasize resistance training is simply incorrect.

James Gaulte

Ray Gardner writes:

Fortunately the definition of a good podcast isn’t whether or not the person being interviewed is widely agreed with. I enjoyed it a lot.

As is the case with most issues in life, the people that make a public voice for themselves (DeVany in this instance) are out of balance. It's difficult to critique them however without also throwing out the valuable information.

The primitive diet is a good idea in the abstract inasmuch it adheres to the principle of whole, unprocessed foods, staying away from refined grains, etc. Saying that we should subscribe strictly to what cavemen ate and didn’t eat however is simply overreaching. The principle is correct, but the legalistic application causes his plan to lurch out of balance.

From practical and academic experience I know that the wind sprint types of workouts are as effective if not more so than long distance running. Anecdotally though I know the best results I’ve ever had was from doing a combination of sprinting and short burst activities with longer runs up to about 5 miles.

So again, we’re talking about balance.


Chas writes:

Shawn, I posted that comment more as a joke than anything else. Obviously, the sprinting was working muscles that don't get much action, so they were naturally a little sore this morning (though I really didn't think they would be this sore -- time to pop some ibuprophen I think). De Vany's comments about jogging rang true to me -- I generally don't like it, but I can't cycle in the winter so I jog.

I will say, however, that about 8 months ago I adopted a "casual vegan" diet and have never felt better. I dropped 10 pounds almost immediately. The diet is this: no dairy, no meat, no sugar/desserts, minimal processed carbs, but I do eat fish. I feel so much better than when I was eating the typical American high-fat diet and exercising my tail off to keep from getting too fat. I'd recommend it to anyone.

Matt writes:

What I found really crazy, is when, at the end, he came out as a creationist.


But seriously, there was so little data to support all of his arguments about the optimal training regimen today.

For example, I have no idea how many miles paleolithic people traveled in a given day. I would guess they traveled further than a person who lives an average modern life, but runs a couple of wind sprints 3 days a week. So why not mix up some sprinting with distance running?

Dave Peterson writes:

So, if I understood Professor De Vany correctly, grains lead to higher levels of insulin in the body. These higher levels trigger a response that stirs the desire for reproduction. If this is correct, would we not be able to observe more sexual activity in a society that consumes more grain? And, if so, is there any data on this, either historically or across cultures?

Ray Gardner writes:

Matt -
I missed the creationist part, but a genuinely biblical view of the world runs 180 degrees contrary to the whole idea of paleo dieting since the bible teaches that man has not been here anywhere near as long as the evolutionists say.

A biblical version of this diet would begin about 10,000 years ago and would necessarily focus on early farming and what foods were available since secular science and the bible agree that farming began about that long ago - give or take.

Matt writes:

Ray-
Thank you for your serious reply to my lame joke.

But it was double funny, because your second paragraph was similar to level of argument made for the paleo dieting. I like this set of ideas and I will use them as an argument for everything I can think of.

Koala writes:

When it comes to dieting, De Vany got part of the picture right. However what he is describing is a diet that is suitable mostly for blood type O. This blood type is the oldest, and has hunter gatherer roots. The fact that you guys talked about sports for half an hour before this is no coincidence because O's are the only blood type into competitive sports (the others have no interest in it whatsoever). He talked about milk, yes, but "Type O" cannot digest milk, this type has problem dairy. But other types AB, B have no problem with this.

De Vany is on the right 'track' in so many ways, he just misses the final and crucial point somehow. When hunter gatherers settled down and started organized farming, yes this was different and in many ways, unsuitable for type O. However, this is when evolution shifted gears and some O's evolved into type A. This type is the 'farmer' blood type and they have no problems eating grains.

But I benefited from this talk, especially the parts on insulin, heart having to be at irregular rhytm so forth, these were good. Just the dieting part needs a little work. For more details on Blood Type Diet, you can search Peter D'Adamo on the Web.

Dmitry writes:

I agree with Ray Gardner saying "Fortunately the definition of a good podcast isn’t whether or not the person being interviewed is widely agreed with. I enjoyed it a lot."

I am not a biologist at all, but I've read somewhere about human dental structure being different from flesh-eaters meaning meat isn't the most frequent ingridient in the diet. What do you think about this fact?

emerich writes:

Folks, I became a subscriber to his "blog," and there wasn't a whole lot there to sink your teeth in. So I thought, maybe it would be worth buying his CDs? Price, $60, shipping, $15. Yeah right. I could have been tempted if there'd been real substance in the blog.

Joe D writes:

Science Daily: High Prevalence of Atrial Fibrillation Found Among Cross-Country Skiers.

http://www.sciencedaily.com/releases/2010/02/100209200756.htm

(15% of long distance skiers vs .5% of general population have indications.)

As a cross country skier but non racer, I have always wondered why the amateur races available consist of solely long distance races, hard to find anything under 25k. My form of skiing takes me on long lazy treks at low speeds, just enjoying scenery, with occasional sprints to get up steep hills. Now I will mix in perhaps a few more sprints!

As a computer programmer who sits behind a desk (ancestor of southern Italian shepherds and French Canadian voyageurs) I seek activities that keep me outdoors all day, summer or winter. I enjoy cycling in summer, the sprints up hills and lazy gliding downhills are similar to skiing. Work, then glide, with long flats in-between.

Also, I was wondering what evolutionary biology had to say about saunas. And specificly drinking beer in saunas (grain was used to make beer long before it was used to make bread, I read recently).

Nico writes:

I don't understand the venom of so many of the comments regarding Dr. De Vany's ideas on diet. I just read his essay in which he expounds on these ideas, and it didn't strike me as quackery at all- then again, I'm not an expert at all, so I'd be interested to hear from some.

At the same time, doesn't it strike you guys that experts in fitness 1) don't agree with each other and 2) don't offer much helpful advice, particularly in eating. In reading De Vany's essay, I'm also struck that he directly addresses the thing that has prevented me from sticking with any fitness routine- they're boring and dreary.

Of the snarkier commenters portrays De Vany as saying that we should avoid carbs all together, and then attempts to pull an 'ahah!' by pointing out that vegetables contain carbs. Buy De Vany directly says in the essay that we should get carbs from vegetables.

This is the challenge I would issue to the skeptics and dissenting experts: is there any harm in following De Vany's prescriptions? If not, why can't people just try it for themselves and see? Some commenters suggested that De Vany is just looking to make a buck, but wouldn't consulting with a professional nutritionist and a professional trainer cost vastly more than the price of his book?

Prof. Roberts- I would be interested to hearing some other opinions in this matter, though perhaps that would be veering too far away from econ. Perhaps some blog posts at Cafe Hayek? Thanks as always for your excellent work!

Most people who enjoyed this podcast enjoyed it because De Vany is a good speaker who makes a rather intuitive argument. His ideas on diet and fitness are intriguing and I don't think that most critics who voiced their own opinions on this comment section would disagree that his arguments make a certain amount of sense.

But as facts go, and as this podcast has consistently advocated, he has absolutely zero data to support any of his arguments. Lots of great anecdotes, sure. But what he presented here was absolutely not scientific and I myself found that to be extremely frustrating.

Clearly this is an economics podcast but it is one that strives for truth and well reasoned arguments that are supported by facts. There is an argument here, and it is even well reasoned, but it's not even remotely supported by facts. That's my one objection.

My second is much more esoteric and has to do with the lack of understanding of evolutionary principles and how poorly they were attempted to be used as support. It's an argument that's harder to articulate than the first to folks who aren't familiar with the fossil record, but I think most of us can agree on the first critique: Lots of intuition, zero data.

Trent Whitney writes:

Following up on the Cole/Stigler New York Times article cited by Prof. De Vany in the podcast and his paper (and linked to in the "Articles" section above)...

Prof. De Vany relies on the work of Cole and Stigler, who make a huge deal out of the fact that Babe Ruth hit 28% of his home runs in the last 6 years of his career, while Barry Bonds hit 26% of his home runs in the last 6 years of his career. They write that "There is no convincing way to demonstrate that Bonds’s performance owed more to drugs than Ruth’s did to his prodigious use of alcohol and tobacco."

I literally am stunned that the sports editors at the New York Times could be so asleep at the switch as to allow this "evidence" to go unchecked. In short, it's logically flawed beyond belief for two reasons:

* First, Ruth was primarily a pitcher in his early years - through 1917, then split time in 1918 as pitcher/outfielder, and was a part-time pitcher in 1919. So he was not a 100% outfielder focused solely on hitting until he was 24 years old. Of course he'd have a higher proportion of his home runs later in his career!

* Second, when Ruth broke into MLB, it was still the dead ball era, when it was a mighty feat just to hit a home run. To wit: Ruth led the American League in home runs in 1918 with 11 home runs (yes - 11 led the league). Of course he'd have a higher proportion of his home runs later in his career, in the live ball era.

Needless to say, Bonds was neither a pitcher early in his career, nor did he play in anything resembling the dead ball era early in his career. This is truly comparing apples and oranges...and anybody who truly knows anything about baseball would spot the gaping holes in the Cole/Stigler argument in a matter of seconds. Again, I'm truly stunned that this appeared in the New York Times apparently unchecked.

James writes:

This sort of nutritional theorizing is totally unscientific. The fact is the data necessary to draw firm conclusions about the effects of diet and exercise are so long-term they are impossible to collect. We have the same problem studying the effects of education. It just isn't practical to do real experimental research on a time frame beyond about 10 years. By the time the study was over you would have to repeat it because the world would be so different!

The best scientists will not come near longevity research for this very reason.

I'd say the only sure knowledge we have is that every minute you spend worrying about your health is a minute not spent on something more productive. Do what comes naturally!

EPZEN writes:

As a physician this podcast was an interesting one. I don't agree with his comments about steroids as they do have an effect on muscle strength which in the talented athlete can make a difference. Therefore, I'm highly skeptical of any of his statistics and like a previous comment I wonder how much steroid use in pitchers affected the data.

His comments about aerobic exercise show an excessive concern. Like anything in life you can find downsides but aerobic exercise's benefits have been clearly demonstrated. I also think his comments about grains are over rated although we as a society do eat too much processed food with minimal nutritional value. Some of the comments about insulin were plainly incorrect.

His comments about meta-analysis I loved as I have always been of the opinion that garbage in equals garbage out and too many meta-analysis studies include very questionable data.

I actually don't mind an economist commenting on medical issues as Russ lets me comment on economic issues:).

Art De Vany writes:

Data and references are in my paper, Steroids, Home Runs and the Law of Genius, which is available at my web site in prepublication form. Same for the diet and exercise literature where the gene research, exercise and diet research are presented in my forthcoming book, The New Evolution Diet, which is to be released early next year.

There is an extensive literature on GH and steroids and their effect on athletic performance and muscle mass. I just posted an article today on my site from the New England Journal of Medicine that shows GH is ineffective. Exercise is the best way to release GH. Steroids do enhance protein synthesis and, with exercise, can contribute to muscle mass. But, the relatively slower FTa fibers are favored over the faster FTx and FTb. Body builders and weight lifters, leaving aside Olympic lifters, do show slower contraction time relative to athletes.

And then there is the problem of the transfer of performance among modalities: strength performance does not transfer over to cognition, speed, agility, or control. If strength and mass were the primary factors, then huge players, weight lifters, or football players ought to be great home run hitters.

The basic problem with the steroid argument is that it is not falsifiable. And, there has been no change according to the statistical distributions that fit the data. The proponents of the argument pose the question as one of having to explain how Bonds or others could have done it without steroids. That is not even testable, as shown by all the various dodges proponents revert to in avoid a real test of the hypothesis. They start with the records and then ask what might explain it. This is a search for an explanation in a missing variable. In effect, they say there must be "something" that explains the records.

They did the same thing when Roger Bannister broke the 4 minute mile.

As for the diet and evolution argument, we really have to go to gene expression. Here is just a bit of what is now known about diet and gene expression from a footnote in my forthcoming book:

"A good deal of aging research has focused on the insulin/IGF-1 pathway, implicating insulin as a key component of the aging pathways. Since insulin is deeply involved in glucose metabolism and storage, this suggests that glucose may be an important signal of the aging mechanisms. The insulin/IGF-1 pathway is ancient and exists in most organisms. When nutrients are abundant, the insulin/IGF signaling (IIS) pathway promotes growth and energy storage but shortens life span, see Wang et al. JNK Extends Life Span and Limits Growth by Antagonizing Cellular and Organism-Wide Responses to Insulin Signaling. Cell (2005) vol. 121 (April 8, 2005).
On how ancient this pathway is, see Barbieri et al. Insulin/IGF-I-signaling pathway: an evolutionarily conserved mechanism of longevity from yeast to humans. American Journal of Physiology- Endocrinology And Metabolism (2003) vol. 285 pp. E1064-E10171.
Dramatic new results that directly implicate glucose in longevity is the study of S. Lee, C. Murphy, C. Kenyon. Glucose Shortens the Life Span of C. elegans by Downregulating DAF-16/FOXO Activity and Aquaporin Gene Expression. Cell Metabolism (2009) vol. 10 (November 4) pp. 379-391. This important article caused the researchers to drop sugars and simple starches from their diets immediately following their discovery and is summarized at Cell Press (2009, November 5) and at Science Daily in 'Spoonful Of Sugar' Makes The Worms' Life Span Go Down.
Following the Kenyon team’s results for worms is another finding in humans that “restricting consumption of glucose, the most common dietary sugar, can extend the life of healthy human-lung cells and speed the death of precancerous human-lung cells, reducing cancer's spread and growth rate.” University of Alabama at Birmingham (2009, December 18). Calorie intake linked to cell lifespan, cancer development. ScienceDaily. Retrieved December 28, 2009, from http://www.sciencedaily.com­ /releases/2009/12/091217183053.htm.
Stress resistance through calorie restriction is discussed in Yu and Chung. Stress resistance by caloric restriction for longevity. Annals of the New York Academy of Sciences (2001). Weindruch et al. Gene expression profiling of aging using DNA microarrays. Mech Ageing Dev (2002) show significant alteration of aging-related gene expression under calorie restriction.
The NED is relatively low in calories and assures a balanced amino acid profile. According to research this combination may reduce aging, see Wellcome Trust (2009, December 6). Balancing protein intake, not cutting calories, may be key to long life. ScienceDaily. Retrieved December 28, 2009, from http://www.sciencedaily.com­ /releases/2009/12/091202131622.htm."

And, yes, brain size is about 10% less than it was 4000 years ago. In an interview at Livescience, November 13, 2009, Professor Steven Hawks noted that the human brain continues to evolve and has shrunken about 10% in the past 5000 years,

More to the point, obesity is associated with reduced grey matter in parts of the brain. See BMI was negatively associated with grey matter density of the left post-central gyrus in obese but not lean subjects. Jagust et al. Central obesity and the aging brain. Archives of Neurology (2005) show that brain mass is reduced as the waist hip ratio increases. See also Ward et al. The effect of body mass index on global brain volume in middle-aged adults: a cross sectional study. BMC Neurology (2005) vol. 5 (23).

This is just economics; a fat body competes for nutrition with the brain.


Russell writes:

Skimming through the comments leads me to wonder if a podcast on methodology and the philosophy of science isn't in order. And one on evolutionary biology/anthropology tied in to economics. I would really enjoy hearing more on these topics from folks who know more than I do (and I don't know much).

To me, science is far more than controlled, randomized trials and a few regressions or ANOVAs. I don't know off the top of my head, but I think there have been a number of famous scientists using their own bodies for experiments leading to real breakthroughs. Surely, there have been a number of quacks - but how does one know ex ante?

Those who are quick to dismiss Art's views on nutrition out-of-hand may be doing so unfairly because they misunderstand (in my view) science in the real world. Waiting until all the data is in or relying solely upon controlled, randomized studies is foolish and narrow-minded, in my opinion. This is particularly true of health/nutrition because each of us has to make decisions on these matters continuously and always in the face of uncertainty. Art's approach strikes me as extremely reasonable given the information and more importantly, time constraints. And EF has been good to me (so I have a strong bias).

Art's analytical approach to the question of the 'roids and the baseball (paraphrasing Bill James) also raises methodological issues. It seems most people start from the premise that steroids lead to more HRs and Art does not. The availability heuristic leads us to think of Bonds, Mac, etc but that's a non-scientific approach. Without knowing much more than what I heard on the podcast, I think Art is reminding us all how truly difficult it is to really know anything.

Great podcast and I would love to hear the methodological and philosophy of science issues touched upon take center stage in future podcasts. Nassim Taleb would be great (again for the third time) to provide some insights on these issues. Some of which I hope he will be covering in his next book or the elongated paperback version of TBS.

Botswana writes:

People here are discussing whether Art's approach to sports/nutrition is 100 % right or not. I think it's fair to say that there is a lot of low-hanging fruit if you want to increase your health.

If you simply stop eating junk-food and start exercising regularly (doesn't matter whether it's jogging or pumping iron) you will improve your health significantly.

These two things will improve your health by 80 % (=subjective estimation). Then we can discuss about how to get the remaining 20 % (100 % being ideal health) - sprinting vs jogging, grains vs fruits, milk or no milk, etc.

Art De Vany writes:

Nassim and I are good friends. He has lost a ton of weight and looks better than he did years ago. He refers to me often in the extended Postscript of the new version of The Black Swan.

Of course, he and I see the importance of extreme events in the same way. My book, Hollywood Economics, is an empirical and theoretical study of extreme events. The newly emerging field of fractal physiology (the heart beat intervals are power law distributed) shows how to do physiology that accords the proper importance to intermittency and variation. The body is an adaptive organism. Homeostasis is not the goal of a physiological, open-ended system. Nor does the second law of thermodynamics apply to an open system.

Long ago, I departed from equilibrium economics and homeostatic physiology. You can see that in my Why We Get Fat paper on my site where I model the Paleolithic energy landscape using a dynamical and statistical model and solve for a fixed point of body mass in the dynamics.

I do not find the active critic emerich among my subscribers, though he claims to have subscribed and read through the blog. He may be there, but he doesn't show up and it would take weeks to read through and understand the complex science I discuss there, something he clearly has not done.

Let's turn the steroid argument around to me. How else do you explain that I am 8 or so standard deviations above the mean health and fitness for my age? I am twice as strong as the average 40 year old male according to a study done by Ruiz and associates at the Cooper clinic. My blood parameters and hormone levels are those of a healthy young man and my risk of cardiac disease, according to the WolframAlpha calculation using Framingham data, is that of a health 36 year old.

It must be my diet and activity, along with my outlook on life. And, yes a clinical psychiatrist examined 8,000 New Guinea foragers and could not find one that was depressed. Currently, about 40% of adults have depression.

I find it amusing that commenters want references in a half hour talk. It would take many hours of a podcast to cover the thousands of references I have read and understood. Being an mathematical economist makes it easy to understand complex systems, such as the human body. Hayek had a background in physiology, if I recall correctly.

Anyway, I am finished with my book and await its publication. I am on to implement a futures contract for motion picture financing, based on the models of my Hollywood Economics. You will be reading soon of its release on a major exchange.

Sorry, just a fan, not an economist. writes:

I'm still trying to decide what I think about poverty being the result of being truly a self-made man.

The diet described sounded like a good way to get one's body more in tune with its origins, and to keep it satisfied.
Although, since the human species is more than just its body, satisfaction is actually just a point of equilibrium.
If you were just a body, simply acting upon your instincts would lead you to satiate your appetite, and that would be the end of it.
Progressing towards happiness or joy, or whatever you want to call it, sounds to me more like a worthwhile goal, than does mere satisfaction, or satiation.
After sufficiently reducing the cost of acquiring adequate caloric intake, the diet that is best pursued by man, is the one that brings the greatest happiness.
The appetites of the body are not perfectly perceived by man's intellect, no matter what diet is being followed, despite that it is through the intellect that the superior component of mankind is manifest. I am specifically avoiding saying that man's intellect is, of its own self, the superior component of man, although it is one way that we have of perceiving man's progress beyond natural instincts.
There is a price to pay for this progress, and a certain duality or disconnect happens, generally speaking. However, seeking ways to overcome that disconnect, by attempting to determine what the body-component of man would instinctually consume, isn't necessarily the best or most efficient way of seeking happiness.
(Although, all else being equal, two people eating the same diet, the own who gains the most weight has the most efficient metabolism, so not even efficiency is necessarily happiness.)
If you don't exist to be happy, or to seek after it, what is the primary purpose of your existence, then?
There are certain guidelines that place the body in a proper relation with the intellect, that allow the soul to achieve the greatest happiness.
Find the one that allows you to progress the furthest you can in that direction.

Brennan writes:

In listening to to the podcast I found my self wondering how the two topics discussed related to each other. How does the fitness or strength of a current day athlete (steroids or no) compare to the fitness or strength of a human in the hunter gather days?

It seems like the athlete, with millions of dollars on the line, would have a far greater incentive to build strength than the hunter who only has to provide for a small family group. Are the modern advancements in health and nutrition enough to over come there degradation of fitness that Art described? Do we have any data on the strength of a pre-agriculture human?

Phillip writes:

Brennan,

I am no anthropologist, but from what I understand, humans in the ancient world and prehistory were in much better shape than we are; even more so than our top athletes. There has been some research on this topic. I heard some on NPR the other day.

I think your question of incentives might be a little off. If you really had to hunt and gather for your family every day, the abstract concept of money really wouldn't matter much.

Check out this funny picture:
http://www.clemson.edu/caah/history/facultypages/PamMack/lec124/evolution.jpg

Professor De Vany,

You are saying that humans have not adapted (in the evolutionary sense of the word) to the change of diet that has occurred within the past 5000 years but somehow have managed to evolve a smaller brain in that same time span. I should say that I agree with the latter and find the former utterly preposterous. I'd love for you to explain the consistency of this argument. But let's ignore that little fact for a moment and just look at brain size.

You, rightfully, state that: "And, yes, brain size is about 10% less than it was 4000 years ago".

You have, however, failed to give me even the slightest bit of evidence that shrinkage of brain size is somehow a bad thing for us a species or for individuals as it relates to their intelligence and ability to survive. Statistically significant and scientifically accepted studies showing a positive correlation between intelligence and brain size within the human species and/or between mammalian species, are clearly required to give your argument (as it stands with respect to brain size) legs to stand on.

saigawa writes:

"And, yes a clinical psychiatrist examined 8,000 New Guinea foragers and could not find one that was depressed. Currently, about 40% of adults have depression."

So much of what De Vany said in the 65 minute podcat (not half hour as the "mathematical economist" wrote") is false but fortunately not bought by those posting here with a scientific background.

Even the above on depression can be seen to be false with a 60 second google search. Closer to 5% and maybe as high as 10%.

I guess just make it up as you go along.

Russ Roberts writes:

saigawa,

Wish you had saved me those 60 seconds and provided that easy link. After a few minutes of search I find studies of the Kaluli people of New Guinea and the phrase "virtually no depression" keeps coming up. That may not be accurate but I can't find your 5% or 10% claim. Please post a link.

saigawa writes:

Hi Prof. Roberts,

Another 60 second search led me to a link stating 5% of those under 19 are at risk of depression. Not good enough... The article I read was from a couple of years ago that stated researchers were a little surprised at finding 5% with depression since they thought closer to 7% to 10%.

So I ran to Wikipedia:

"In North America the probability of having a major depressive episode within a year-long period is 3–5% for males and 8–10% for females."
Let's say 7%. It ain't 40% as the guest wrote.

Oh, I was Arc of a Diver who got a temporary ban for crude language. For those curious, I used a word many economists use when they hear horse$#!+

I also wrote it was the worst econtalk I'd heard, although standards are high, and one has to be the worst, right? The rest have varied between very good and excellent, so batting around .990, not bad.

It _was_ entertaining in an "Econ Talk enters the Twilight Zone" sort of way, and the guest seems like a very interesting person. But there was also quite a bit of...

[N.B. saigawa: You got banned not so much for your crude language, but primarily for not responding to the emails we sent you discussing it. You've supplied multiple email addresses with your comments, all of which we tried, some of which failed, and to none of which did you respond. We give people plenty of opportunity to discuss comment problems in email. If you supply a false email address and do not respond to us, we are unable to talk out even the most minor infraction. Your originally-offending comment could easily have been posted with a simple language edit to remove the four-letter word. If you would like your comment privileges restored, please email us at webmaster@econlib.org.--Econlib Ed.]

Art De Vany writes:

Adam, who knows if a smaller brain is good or bad? I don't know, but I do have a large brain. Interestingly enough, in the last graduation at UCI I attended, there was a shortage of large sized Mortar Boards in the allotment set aside for the faculty, but not for the students.

There are number of theories proposed by scientists on that score, including the one I mentioned that we had to be a bit smarter to survive in the Ice Ages. Smartness being relative, but surely the cognitive demands of surviving the Ice Ages were large. Spencer Wells in his Deep Ancestry book argues that it was during this time that the brain underwent its evolution to a more modern brain.

There are a number of alterations in the human genome in the last 10,000 years, most having to do with disease resistance, and adaptation to diet. One, of particular relevance, is that the alpha-actinin-3 protein gene has been supressed in nearly 20% of humans, particularly in Caucasians and Asians. This makes us less physical---elite athletes express this protein---but energetically more efficient. Maybe a bad thing in a world where nutrition is abundant.

The qualification on depression is that by the time they reach their 50s, or if they are college students where the incidence is high but not as high as 40%. There is a psychiatrist who treats subjects with the principles of hunter gather lifestyle: contact with nature, deeper networks of relations, a Paleo type of diet, and playful exercise.

All should know that I started on this topic by giving content away for years, since about 1995 only began charging a couple of years ago because I wanted to screen out the insincere and misleading cranks that haunted my site. There are now thousands of blogs out there repeating my message. And several books that adopt the practices I have long advocated.

Open your mind up a bit and look around. The old paradigm, fat bad, carbs good, energy in energy out homeostatic view of weight and body composition is falling away. Why is it that people so fear the loss of their world view?

Russ Roberts writes:

Art,

I have no trouble with you charging for your insights. What I find fascinating is the anger and hostility in the comments because you don't give stuff away or maybe because you have a financial interest in selling your ideas.

Almost everyone has a financial interest in selling their ideas.

Everyone's ideas should be treated skeptically. But the sweet spot for skepticism is hard to hit.

Art De Vany writes:

Russ,

The blogosphere is a place for free things, though that is rapidly changing. I had enormous resistance and criticism when I announced I was going to a subscription system. Many wished for it to fail. I don't get it either.

Maybe they are depressed. People value things more when you take them away than when you give it to them. The thing about my site is that I don't sell vitamins, hormone therapy, or snake oil. All I sell is my content. Rather strange, I know. And, that content makes its way into public venues through other bloggers, though they generally respect my IP.

What I should have said about depression is that by the time they reach their fifties and sixties, 40% of people have experienced depression. The people who, correctly, found my error are confusing cross-sectional data with panel data---a time series of a cross-section. For most people, depression is episodic with spells of varying depth (and despair). The chronically depressed seldom find relief from it, and the longer it goes on, the more likely are further spells.

Joe Kash writes:

I do not have any problem with a person charging money for their internet content. Based on this podcast, I have no interest in spending my money on this content. I was disappointed with what I usually find to be a very interesting podcast.

I am not an expert in economics which is why I love this podcast. I have learned much. I do know more about biology and nutrition particularly in relation to clinical data. I am most disappointed by Dr. Prof De Vany's appearent muddling of the issues of scientific hypothesis, theory, molecular studies, cellular studies and clinical data. When it comes to the human person the most important issue is clinical data. The molecular and cellular studies can help one propose a hypothesis or theory concerning the clinical setting. Unfortunately the majority of these hypotheses turn out to not be clinically significant or marginally significant.

I have seen many cancer patients go to Tijuana for the Gershan diet, Texas for anti-neoplastins, Linus Pauling for vitamin therapy, and Illinois for low dose insulin therapy. There are a million and one cures of cancer and there are a million and one preventative strategies. They all are based on science including molecular studies, cellular studies and/or evolutionary theory. They all can sound very convincing. I would put Prof. De Vaney in the genre. He may be right and he may be wrong but he has no good clinical data to make such emphatic recommendations!

I subscribe to my Polish grandma's advice concerning diet: variety and moderation. She didn't have a website and didn't have cellular or molecular data to back up her claim but she was a great cook!

ringo starr 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 EconTalk.--Econlib Ed.]

Ak Mike writes:

I thought this was an interesting and thought-provoking interview, and I appreciate Prof. De Vany continuing to participate in this discussion.

Prof. Roberts, I think you are missing the point of the comments regarding Prof. De Vany's commercial interest in his theory. The problem is that it reduces his credibility, because he can't really change his mind. If he makes lots of money by selling his theory, which includes specific suggestions as to what to eat, etc., then he can't look at counter-arguments objectively, and he can't say "you know, I was wrong."

You, Prof. Roberts, have freedom to do so. You could re-read some progressive economists, and tomorrow post on your blog a retraction of your support of Hayek. You would suffer no loss of employment and no significant diminution of your income. Because you have no financial stake in your views, they are more credible and persuasive.

That doesn't make Prof. De Vany wrong, it just diminishes his credibility. Also diminishing his credibility is his use of bad arguments. I'm no biologist, but I can tell that this sentence: "How else do you explain that I am 8 or so standard deviations above the mean health and fitness for my age?" pinning his alleged health on his diet and exercise regime is a very poor excuse for an argument.

Obviously, a sample of one person is merely an anecdote. It could be that he just eats less and gets some exercise, not that he eats the particular kind of stuff he eats or gets the particular kind of exercise he pushes. It could be that he has great genes. Since he has money at stake, it could be that he is shading the truth a bit about his glowing health. Yet his comment says it "must be" his diet and exercise along with his outlook. This is the same logic that condemns vaccination because your child got autistic after having his shot.

None of this makes Prof. De Vany wrong. But non-experts like me have to use these indications to evaluate unusual and idiosyncratic theories like those of your interviewee.

Art De Vany writes:

You guys are so serious you don't seem to know when you are being made fun of. That line about me being 8 standard deviations out is the "steroids must have done it" made by proponents of the deviation in home runs, not mine. Parody is seemingly difficult for some and lost on Ak. As for my publishing a book and therefore being locked into a point of view, I think that applies to most scientists who have their credibility at stake and defend their prior work unduly. It is a human failing, but it applies to a good deal of the fat is bad diet research that has pervaded the literature. Some associations and government agencies cannot easily abandon their prior recommendations for fear of losing credibility and donors.

So, it is a general problem of "official" prononcements by government agencies, professional associations, and health groups such as the AHA and ADA. Once their positions are announced it takes a large body of evidence to convince them to change. The government food pyramid has not changed in years in its basic recommendations in spite of alarming evidence pointing to its errors. It persists in order to sell agricultural products.

As for me, I think the book will put new arguments and evidence out there for all to judge. To anticipate that I will be looked into the point of view I espouse in the book, without even knowing what that is until the book is published, which seems to be Ak Mike's argument, is perilous forecasting. I assume he will not buy the book. He really ought to evaluate the evidence, one data point being me and others being thousands of others who have shed weight and depressive mood following my approach. Based on his argument, he should not buy any book that sells well because the author, who presumably believed and had evidence to support his arguments, cannot change his or her position later.

Then again, perhaps the book makes points that are true? No change required.

As for Joe's argument, he makes none. Calling my arguments a muddle is not an argument---it is the mark of one who has no evidence to present. Saying "I have a background in biology" means nothing. What are your publications, degrees, and other evidence that support your qualifications to make such a impolite and poorly documented case?

In discarding all evidence but for clinical trials, most of which involve pathologies or illness that may have nothing to do with healthy people (example: the bulk of metabolic studies are done on the obese, which have only limited relevance for healthy people as many scientists argue), Joe is dismissing laboratory work, such as the Kenyon research I cited on c. elegans and other work on mice as well as humans, and epidemiological studies as well as antropological evidence and nutritional ecology.

One thing I did not do was to call anyone stupid, ignorant, muddled, or just in it for money. Too bad so many commenters do not have equal manners.

Its been fun. I think that is it for me.

Joe Kash writes:

Prof De Vaney,

I certainly did not call you stupid. I also did not call you wrong. The "muddle" is that cellular data, molecular data and animal models only prove what happens in the cell, at the molecular level and in the animal. The extrapolation assumes that this will be the case in the human.

If you have well conducted studies in humans and not just anecdotes then it would be nice to see this data. Even 100 or 1000 examples of people who eat as you do and are physically healthy in their old age are anecdotes.

I recently listened to the guy who made it clear as day that cancer and heart disease are primarily a result of mercury tooth fillings. He sited cellular and molecular data and anecdotes. He also sells info on his website of how to properly detoxify the body before having the mercury fillings removed.

I know a number of well respected doctors that sell Juice Plus. They send me cellular data, molecular data and anecdotal information trying to convince me to promote this to my patients so as to keep them healthy.

I can go on. As I said, you might be right. I don't need to provide you with the data to prove you to be wrong. You need to provide me clinical data if I were to think you to be right. Until then I still will lump you into the thousands of believers who are certain they have figured out the perfect diet.

I wish you good health.

Sebastian writes:

Among the arguments about diet and exercise, the one I found most strikingly wrong was that somehow jogging is bad for you because it's not what humans evolved to do. Incidentally, if there is one thing and one thing only that the human body is designed to do, that thing is to jog. We are physically inferior to animals in every respect except our capacity to run for a long, long time.

As for what modern day hunter gatherers think about jogging, I think a significant percentage of them think its a part of daily life. Endurance hunting is one of the likelier hypotheses as to how early humans hunted(it requires no tools, after all). Here's my 2 seconds of research reference for that:
http://en.wikipedia.org/wiki/Persistence_hunting

I thought it was extremely funny that you talked about the woes of having a smaller brain. Wouldn't an economist applaud human's ability to downsize, streamline and make more efficient the structure of our most important feature? I thought doing more with less was a fundamental Good Thing, from an economic perspective. I don't necessarily agree that you can usefully apply economic principles to evolution, but this one is a no-brainer. There is no proof that we are getting less intelligent(note that there is no good proof that we are getting more intelligent either, nor is there a great deal of understanding as to what being intelligent even means anatomically and at the molecular level).

The fact that Art or Russ would die in a matter of weeks if they were dropped in the middle of a forest 10 000 years ago has absolutely nothing to do with evolution(except to the degree to which our immune system can cope with ancient pathogens). It has everything to do with a 40-50 year old guy who grew up in suburbia not having the cultural knowledge needed to scrounge for food, build shelter etc etc. Give a 2009 born baby to a 5000 BC mother to breastfeed(for the immune system boost) and educate. I highly doubt he would fail to do just fine. It's all cultural and not at all genetic.

Tim Wright writes:

I enjoyed the podcast, I find it interesting to hear out of the mainstream ideas and thoughts. I am also very interested as a layman on evolutionary theories of man. However, I think it is really easy to formulate theories about man's past and what we are. But it is very difficult to prove them, or as Karl Popper and others state disprove them (Question: what evidence would be accepted to disprove Prof. De Vany's ideas?). One good book that looks at the research of evolutionary theory is Adapting Minds by Buller. One idea I got out of the book is we are always evolving. I don't want to go back and find out who we were 10,000 years ago and try to emulate their lifestyle. I want to see what we can do and want to do today. Evolution does not stop. We are never perfectly tuned to a particular time or place. Who we are as humans is not written in stone.

From the other discussion threads about happiness. I wonder if we really have been evolved to be generally happy. We evolved to procreate, to continue the species. I am not sure if happiness is required. When we see people happy, why? Is it a snapshot of time? When we see people depressed, is it because we are out of our "natural" environment? I see these questions very hard to answer.

I wish Prof De Vany the best on his research but I just can't give up chocolate chip cookies. My great grandmother lived on a farm, put in hard long days, ate dairy foods and grains and lived to be a hundred. Granted my life is not as active as hers but I see no reason to give up dairy and grains. However reducing my consumption is probably good idea.

Ray Gardner writes:

For those who seem to be confused about why the bulking effect of steroids does not help with bat speed i.e. slow twitch and fast twitch muscles, think of the following:

Why can't bodybuilders jump higher than lean muscled athletes?

Look into plyometrics, and what it takes to develop a good vertical.

Ak Mike writes:

Prof. De Vany - your theories may certainly be correct, and I agree that the best way for me decide whether I think you are right is to read your book and evaluate your evidence. The fact you have a financial stake in your system does not imply that it is wrong.

But it does mean that in evaluating your theory, I can give no weight to the fact that you support it. With Professor Roberts, as far as I can see he will suffer little in the way of consequences if he changes his mind - so the very fact that maintains a particular position is, to me, entitled to some weight.

With you, on the other hand, you will lose a lot of money if you publicly change your mind about your system. So I know that your book must be read cautiously - that you are an advocate and not impartial. That's OK - it just has to be taken into account.

Lloyd Rochester writes:

Could someone post a link (preferably Wikipedia) on the economic principal or law that Art mentioned?

"half the papers in a department are written by the square root of the number of participants. Human productivity."

I am an engineer and in the industry there is mention of what some call the "20/80 rule". That is 20% of the people do 80% of the work. I would like to compare what Art mentioned to the "20/80 rule".

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