Good Calories, Bad Calories
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If you spend much time at all trying to follow the never-ending headlines on diet and nutrition, you are probably familiar with feeling like a wide-eyed kid in a snake oil shop. One week fat is the root of all evil; the next it might just save your life. One week carbs are the center of a healthy diet; the next they are the cause of all your rolls. To actually determine which of these studies is accurate and which is overblown would take a background in the scientific method and hours upon hours of original research in esoteric medical journals.
You most likely don't have that kind of expertise or time, but lucky for all of us health journalist Gary Taubes does. In his new book, Good Calories, Bad Calories: Challenging the Conventional Wisdom on Diet, Weight Control and Disease , he exhaustively researches the last 100 or so years of medical and nutritional research in order to separate myth from reality. In the process, he uncovers a scientific system -- from training to research to funding to public education -- riddled with institutional bias and substandard rigor. AlterNet caught up with him during his book tour and asked him some questions:
Courtney Martin: How did you become interested in the nexus of diet, obesity and disease research?
Gary Taubes: It just happens to be where my particular journalistic obsession took me. I began my career in the early 1980s writing about physics. I then became fascinated with the extraordinary challenge of doing good science and how hard it is to get the right answer after I lived at a physics laboratory for the better part of a year and watched some extremely smart physicists discover nonexistent elementary particles. I then spent three years working on a book on cold fusion, a scientific fiasco, because I was fascinated with how something so obviously wrong could become such a big deal. Afterward, friends in the physics community suggested that I should look into the bad science underlying the belief that electromagnetic fields cause cancer. That conclusion was based on the science of epidemiology, and suddenly my obsession had taken me from physics to public health research. From there I just followed the bad science -- first writing about observational epidemiology itself, then the controversy over salt and blood pressure, then dietary fat and heart disease, and then obesity and the question of why we gain weight.
Martin: You do such compelling, exhaustive research. Please explain your process.
Taubes: I'm just inherently skeptical. I ask what seem like obvious questions -- can diabetes be caused by sugar, for instance, or if obesity is caused by eating too much, why doesn't eating less reverse the process -- and then I go looking for the answers. I don't like taking anybody's word for something so important, so I look for the actual data, which often means following the references in the relevant papers and books backward in time until I eventually get to the underlying data themselves or find that they don't exist. I also like to talk to the researchers who were directly involved with the relevant studies. This was something I learned in my physics writing. One Nobel laureate who ran a physics laboratory told me that he liked to go around the lab at night and talk to the graduate students directly because "they hadn't learned how to lie yet." I like to talk to the people who actually did the experiments in question -- the graduate students if necessary -- because they'll know all the ways they could have been fooled by their equipment, even while their superiors might be trying to gloss over those inadequacies to make their points.
Martin: You write that the "practice of science requires an exquisite balance between a fierce ambition to discover the truth and a ruthless skepticism toward your own work." Why does it appear that medical scientists have had such a hard time striking this balance?
Taubes: The problem with medical and public health research is that those who do it suffer from the all too admirable desire to save lives and ameliorate human suffering. Doing good science takes extreme patience. You come up with a hypothesis, and then you have to rigorously test it. That's the ruthless skepticism I was talking about. It's the testing that's the excruciatingly difficult and time-consuming part of doing science. It can take decades of experimental tests before it becomes a reasonable bet that your hypothesis, and not some other [idea] that you never even thought of, might be right. But people go into medical and public health research because they want to help people; they want to save lives. They know that hundreds of thousands of Americans, for instance, maybe millions, are dying every year of heart disease and cancer and diabetes, etc., and so they don't believe they have the time to rigorously test their hypotheses.
Martin: How does the structure of the funding process for science encourage "wishful science" -- "based on fancies, opinions and the exclusion of contrary evidence?"
Taubes: Probably in many ways, but the one that comes immediately to mind is that funding agencies like to support studies that will give positive results, and they like to support studies that themselves support the beliefs of the funding agents -- i.e., the dogma. So it's hard to get money to really test a hypothesis, because such a test implies that you might find out that your hypothesis is wrong and not worth pursuing further. And it's certainly hard to get money to pursue a hypothesis that conflicts with the establishment's beliefs, because everyone involved with deciding whether your grant proposal is worth funding will also believe that you're dead wrong about what you say, and so why bother spending money to find out? The result is a world in which, in general, the funding helps to assure that only established beliefs are tested, and when they are, that they're confirmed -- whether they're actually right or not.
Martin: Part of the problem, as you see it, is that something is often lost in the translation of medical science research to the general public. How can we remedy this loss? Does the average American need more sophisticated scientific training, or do experts need to change the manner and timing of their communication?
Taubes: I'm obviously hoping that one way to rectify the problem would be to write a compelling book that explains where the science went off the rails and provides an alternative hypothesis that could then be tested. I'll let you know if it works, although at the moment I'm not particularly optimistic. The purist would say that eventually science will right itself, so given time and patience, the researchers will slowly work around to the right answer. So maybe we just have to wait another half century or so, and we'll find that the scientific process really does work in medicine and public health just as it does in other fields.
Martin: Do you think that medical experts have too much public respect?
Taubes: I think they get too much respect from health journalists, who tend to see their jobs as faithfully translating into lay English whatever the medical and public health authorities tell them. Health journalists (or at least the worst of them, who are the ones that regrettably dominate the field) seem to think that if you give someone an M.D. or a Ph.D., like the Wizard of Oz, you're bestowing on them the position of unimpeachable source. I wish that was actually the case, but it's just not, and the sooner health journalists take to their beat with the same kind of skepticism that political writers take to the politicians they cover, or even sports writers to the ballplayers and athletes, the better off we'll be. On the other hand, I do think that the lay public has become jaded and skeptical over the years, undone by the here-today-gone-tomorrow nature of the latest medical wisdom. The problem, though, is still, who are you going to believe if not your doctors? And who are your doctors going to believe if not the "experts" who write the articles in the medical journals? That's what so messy and inconvenient about having a journalist come along and say that they got it all wrong in such a vitally important field. Do you then bet your life and health on the journalist, learned as he may seem, or on the supposed experts? That's a tough decision.
Martin: Given that the last half century of research "unequivocally" supports the hypothesis that obesity is caused not by too many calories in and not enough out but by the "balance ... between the calories -- in the form of free fatty acids, glucose and glycerol -- passing in and out of fat cells," why has the positive-caloric-balance/overeating hypothesis taken such hold of the public imagination?
Taubes: I wouldn't say that it "unequivocally" supports it. I would say that it provides compelling evidence that this is the case. That said, the positive-caloric-balance/overeating hypothesis has taken such hold because both the public (or at least the lean public) and the doctors can't imagine that obesity isn't caused by gluttony and/or sloth. It seems obvious, and the first law of thermodynamics seems to insist it's true -- even though it doesn't. What's more, there was always this belief that if you allowed fat people to believe that their condition was somehow preordained by biology and/or genetics, you were condoning their gluttonous and/or slothful lives. So even those researchers who suspected that obesity was caused by a genetic predisposition and so might be unavoidable up to a point, would still argue that the obese must just try harder than the rest of us to eat less and exercise more. The other problem, as we discussed, is that the relevant portion of the medical community studying obesity hasn't got a clue what science is all about, and so they have found it easy over the years to ignore the copious evidence that refutes their hypothesis and pay attention only to the few observations that seem to support it.
Martin: Describe the legacy of the Atkins craze in our understanding of the causes of obesity and disease.
Taubes: Here's the problem: Atkins almost assuredly had it right -- that we get fat because of the quantity and quality of the carbohydrates in the diet and their effect on insulin. But he was advocating high-fat/low carb diets at a time when the medical establishment was buying into the idea that those exact diets caused heart disease. So the establishment doctors felt they had to put a stop to Atkins' seditious beliefs. They came out adamantly against the diet itself and, in effect, insisted that the underlying biology of fat accumulation was irrelevant to obesity -- a disorder of excess fat accumulation -- because that supported entirely what Atkins was saying. We've been dealing with that fallout ever since. Anything that smacks of Atkins is considered old news, somehow, and not worth addressing or taking seriously. And because people tend not to stay on the Atkins diet -- thus the "Atkins craze" -- physicians, health journalists and the dogmatists in this business tend to see this as a reason to reject the underlying science as meaningless. (Imagine if we all took the same line on cigarettes and lung cancer: Because most smokers fail to successfully quit, the fact that cigarettes actually cause lung cancer must be irrelevant to the public health. Weird, huh? But that's the same logic.) One of my goals is to get these professionals to understand that it's not about the success rate of the diet but what actually causes obesity. Then the success rate itself might improve considerably, as well.
Martin: Why is obesity so often framed as exclusively a contemporary problem?
Taubes: For starters, researchers and public health authorities simply confuse obesity and the "obesity epidemic." We've been getting fatter over the past 30 years, and so these "experts" somehow take that to mean that obesity wasn't a problem at all prior to this modern era. And because these people think they know what the truth is -- obesity is caused by overeating and sedentary behavior -- they see no reason to do the kind of research that might establish whether [that claim] was indeed true and made any sense whatsoever. One of the things I do in the book is point out that it is relatively easy to find populations prior to the 1960s that were living in extreme poverty, eating substandard diets, low in calories and fats, which had extremely high rates of obesity, within the range that we're seeing today. If I were an obesity researcher, I would be plenty embarrassed that I never thought to do this myself and waited for a journalist to come along and say that we can learn some valuable things by paying attention to the history.
Martin: What would you target as the three biggest myths currently held about obesity?
Taubes: That the difference between calories consumed and calories expended tells us anything meaningful about why we get fat. That eating less or exercising more are viable treatments for obesity and overweight. That all nutrients -- fat, carbohydrates and proteins -- have equal effects on our propensity to gain weight -- in other words, that a calorie is a calorie is a calorie, as nutritionists are always telling us.
Martin: You write that the "enterprise" of diet, obesity and disease research "purports to be a science and yet functions like a religion." In what ways?
Taubes: Simple. The researchers and authority figures in this business seem utterly uninterested in finding out whether what they believe is true or not. It's as though their God, whichever one that might be, told them that obesity is caused by eating too much -- by gluttony and/or sloth -- and so they believe that unconditionally, and no amount of contradictory evidence, no failure to explain the actual observations can convince them to question it. They have unconditional faith that they know what the truth is, and there's no place for this kind of faith in the pursuit of science. Science requires skepticism to function. Religion requires faith.