Soon after I posted my review of Why We Get Fat And What to Do About It, I emailed Gary Taubes to ask if he had time for a written interview. Gracious as always, he agreed to answer a long list of questions. Here’s our Q & A.
Fat Head: How soon after finishing Good Calories, Bad Calories did you decide to write Why We Get Fat?
Gary Taubes: Well, even before I was finished with GCBC, I was discussing with my editor my suspicions that what the world wanted — or at least what my friends wanted — was the 200-page, intelligent person’s guide to weight loss. But I couldn’t write that one first, and I felt compelled to cover the subject at length and in detail. The result was GCBC.
About a year after the book came out, it became clear it wasn’t going to do what I had hoped, which was reach a large audience and induce the public-health types to take the ideas seriously, because they weren’t going to read a 500-page book that implied they got everything wrong. So that’s when Why We Get Fat started to come together in my head.
Fat Head: Since you’re a science wonk, did you find it easier to write for the scientific community, which was your intended audience for GCBC, or for the general public, which is the intended audience for Why We Get Fat?
Gary Taubes: I find it easier to write long than short and always have. I want to give all the details and all the supporting information, and I’ve never had the gift of synopsizing. That said, the first two-thirds of WWGF was relatively easy to write because it was based on these lectures I’d been giving, during which I’d honed a lot of the material — not unlike comedians (as you’ll understand) who hone their stand-up routines.
Fat Head: In Why We Get Fat, you managed to take some pretty complex science that you’d already presented in GCBC and make it much easier to understand. So as a writer, you must’ve been constantly asking yourself “How can I explain this to a general audience?” What was your process for simplifying the science without dumbing it down? What was the answer to “How do I make this simpler?”
Gary Taubes: Again, a lot of this came from the lectures. And indeed, in an ideal world the lectures would last 90 minutes to two hours, but when you give grand rounds at a med school, for instance, you have to limit it to 45 minutes to leave time for questions. So I was being forced to think in terms of simpler and shorter. Then I knew that I wanted this book to be small and tight and readable, and I did everything I could to make it that way. And yes, finally, as a science writer, I’m always asking myself, “How can I explain this to a general audience? How can I simplify the science to the point that it is barely noticeable?” In fact, often the best science writing has no noticeable science at all.
Fat Head: A lot of people found Good Calories, Bad Calories intimidating because it was heavy on science. In interviews, you’ve explained that you had to decide at some point if GCBC was going to be written for a lay audience or a medical-academic audience, and you chose the medical-academic audience because they’re the ones handing out the bad dietary advice. So … now that you’ve written a book that’s simple enough for the average high-schooler to understand, do you think more doctors and nutrition researchers will finally grasp what you’ve been trying to tell them?
Gary Taubes: Short answer, yes. I think this book will be harder to ignore than GCBC, and the better it sells, the more difficult it will become to ignore.
The idea was someone would say to them, “Have you seen this book that debunks calories-in-calories-out?” And they would sigh, or roll their eyes, and say no. Or maybe someone would give them a copy of the book, and get the same response. Then they’d throw it in their briefcases, take it on an airplane, open it up in a moment of intense irritation or because they forgot to bring other airplane reading with them, and find themselves drawn in first by the anecdotes — Hilde Bruch and all the fat children of New York in 1934 — and then by some of the ways of thinking about obesity that they’d simply never considered before.
And a lot of these people are excruciatingly smart; they’ve just never had reason to question their beliefs before on why we get fat, as I hadn’t until about eight years ago. Given the opportunity to do it, I think they will be open to the ideas in the book.
Fat Head: One of the opening sections of Why We Get Fat is titled Thermodynamics For Dummies. Was that directed at me personally? Because that would hurt my feelings.
Gary Taubes: Well, I wasn’t going to mention it if you didn’t, but…
Fat Head: Wow, look at the time! I’m sure you probably have to go, so —
Gary Taubes: No, no, just kidding. It just seemed like the obvious title.
Fat Head: Okay, good. You studied physics at Harvard, earned a master’s in aerospace engineering from Stanford, and pretty much lived in a physics lab for a year while researching a book about particle physics. And yet all over the internet, I see critiques of Good Calories, Bad Calories in which the reviewers claim you failed to consider the laws of thermodynamics while writing it. Did you, in fact, forget everything you learned about physics once you became interested in nutrition science?
Gary Taubes: Well, I was thinking the same thing a couple of years ago when I was on the Larry King Show and Jillian Michaels, the trainer from The Biggest Loser, gave me a lecture on thermodynamics — her version — on national television. I remember sitting there at the time thinking, “I did study physics at a pretty good college; I think I understand this.” And I didn’t even respond to Jillian because I didn’t know what to say. I was literally speechless. Surely, one of the high points of my life to date.
Fat Head: I found those critiques rather odd, considering that Good Calories, Bad Calories includes an entire chapter titled Conservation of Energy, in which you wrote at length about the laws of thermodynamics and how nutritionists misinterpret them. How do you deal with criticisms of your books coming from people who clearly haven’t read them?
Gary Taubes: The knee-jerk response is always to assume that the people who criticized the book haven’t read it, and I try to avoid the knee-jerk response. Still, I always want to ask them, “Did you read the book?” Because it usually seems pretty clear they didn’t. It happens all the time.
I have a chapter in the new book discussing how it is quite possible that anyone who loses weight on a diet does so because they reduce either the quantity of carbohydrates consumed or improve the quality — even on low-fat, low calorie diets this is likely to be the case, counter-intuitive as that may seem.
Then I get a review in the health section of the New York Times from a physician, and she ends the review with this pat response that humans come in wonderful variations, so some diets work for some people and other diets work for others. And I wanted to call her up and ask, “Did you read the chapter on why diets work? Do you really have information that I don’t have that makes you certain what you’re saying is true? Because it very well may not be …”
Fat Head: In addition to having a background in physics, you’re a rather tall and athletic person who played college football. Do you ever want to just haul off and smack some of these people?
Gary Taubes: I boxed, too, as an amateur. Painful, short, ugly career. That said, I wouldn’t be human if I didn’t have that response, but I try to let it pass. My wife is always telling me it’s counterproductive, and she’s probably right.
Fat Head: Just hypothetically, then, let’s say Jillian Michaels decides to give you another lecture on the laws of thermodynamics and the debate escalates into a physical confrontation. Who should I bet on if there’s some sideline action? You’re bigger, but she has a background in martial arts, so I think it could go either way.
Gary Taubes: Bet on Jillian. She kicks me once in my arthritic knee — old football injury, no cartilage — I go down in a heap, and that’s the end of it. Now if I were still in my 20s, I’d say take the points.
Fat Head: Why We Get Fat includes a fair amount of new information, so obviously you’re continuing to study the latest research. Have you changed any of your beliefs or conclusions since Good Calories, Bad Calories was published? If so, what?
Gary Taubes: I’m not actually studying the latest research as much as I’d like. I have two small children now, and they tend to take time away from obsessive research. I have come to realize that some of the details I discussed in GCBC were incorrect, and I’m sure I’ll learn about more as time progresses. Other than that, nothing much of significance has changed. That could either mean that the data continue to support what I say, as I believe they do, or that I’m so close-minded that I’m not paying attention to the evidence refuting my ideas.
Fat Head: Since you claim in your books and speeches that much of the conventional wisdom about nutrition and health is wrong, you of course attract rather a lot of criticism and have many detractors. Do you ever lie awake at night worrying that any of your fundamental conclusions will turn out to be wrong?
Gary Taubes: Yes. But not as often as I lie awake at night worrying about other things. Three to five in the morning, I can worry about just about anything and often do.
Fat Head: You were inspired to begin the journalistic investigation that eventually led to Good Calories, Bad Calories when a researcher told you, “If you really want to see some bad science, you should look into some of this public health stuff.” Dr. John Ioannidis, who has been on the research faculty of top-flight universities and also written extensively about flaws in research, says that as much as 90 percent of the medical research doctors rely on is flawed. Why is so there so much bad science out there? How are the bad scientists getting away with it?
Gary Taubes: Actually, there’s an old line I like from a physicist and philosopher of science named John Ziman, who said something to the effect that 90 percent of the stuff in the scientific journals is wrong and 90 percent of the stuff in the textbooks is right, and the process of science is distilling the truths from the former into the latter.
So in part it’s the nature of science in general. It’s really hard and it takes quite a while for reliable knowledge to mature. In part, as I suggest in GCBC, science was a European invention and I think there was a culture of science — of knowing how to think, how to be relentlessly skeptical and rigorous in trying to tear down one’s own hypotheses — that evolved in Europe but never crossed the Atlantic after the Second World War.
In physics this culture did make it across, because we needed the European physicists to build atom bombs and hydrogen bombs and compete with the Soviets during the cold war. Back when I used to write about physics, the physicists would say that the best thing that ever happened to American science was Hitler, because he chased all these brilliant scientists out of Europe and over to America. But they were embraced in physics. All the great physicists of the mid-20th century were European émigrés, or virtually all of them.
In medicine and public health, we wanted little to do with them and, as a result, the way post-war researchers approach science in these fields has little of the rigor necessary to get the right answer. There’s also a problem that medical researchers and public-health researchers are dealing with human beings ultimately as their subjects, and if they want to do rigorous experiments to find out, for instance, what foods will maximize or minimize our chances of living to 100, the necessary experiments are ludicrously expensive. So the people in these fields long ago rationalized why they didn’t have to do these experiments, and why they take leaps of faith instead. But good science happens to be incompatible with leaps of faith. This is why I often wonder if good science can ever be done in these fields.
Fat Head: Even though there’s some new information in Why We Get Fat, the alternative hypothesis you present is pretty much the same as in Good Calories, Bad Calories: carbohydrates drive up insulin, and elevated insulin drives fat accumulation. Your critics often point to populations who eat a high-carb diet — Asians, Kitavans, etc. — as evidence that you’re wrong, since people in those populations don’t generally become fat or diabetic.
Gary Taubes: Well, sometimes I just want to haul off and smack–
Fat Head: Careful, your wife may read this.
Gary Taubes: Oops. Sorry. As I discuss in GCBC, it’s quite likely that sugar — by which I mean a roughly 50-50 mixture of glucose and fructose — is the trigger that first sets off insulin resistance and then the vicious cycle from eating all carbs that leads to obesity, diabetes, etc. And these populations — Southeast Asians, in particular; I’m not really familiar with the Kitavan story — ate excruciatingly little sugar. This, to me, is a primary piece of evidence arguing that sugar may be the necessary trigger. That would explain why when the Asians come to the U.S., they do start succumbing to these metabolic disorders. They start eating more sugar.
Another possible explanation is that the carbs these populations consumed, until very recently, were low glycemic index carbs — not highly refined rice and wheat. There are many variables that could explain it, which is one of the reasons observational evidence like this is so potentially confusing. You have to do clinical trials — i.e., experiments. It’s the only way to get to the truth.
Fat Head: My reply to people who tell me the Kitavans live on starches and therefore I can too is that I’m not a Kitavan. Do you think heredity plays a role in how well we tolerate carbohydrates? Since most people of European extraction can easily digest milk while 90 percent of Asians are lactose intolerant, it’s clear there were different dietary adaptations in different areas of the world.
Gary Taubes: Yes. Heredity and the length of time that a population has been exposed to the carbohydrates in the diet is an important factor, and I discuss this in GCBC. It’s an idea that Peter Cleave gets a large part of the credit for.
Fat Head: Dr. Robert Lustig insists it’s fructose that makes us insulin resistant, not starchy foods. If he’s right, then it was the Coca-Cola and Captain Crunch that turned me into a fat kid, not the mashed potatoes. But as an adult, I’ve avoided sugar yet found that starches most definitely make me gain weight. So assuming for the sake of argument that Lustig is correct, would you say that once fructose has done the damage, we lose our tolerance for carbohydrates in general? If so, why?
Gary Taubes: That’s exactly the possibility I’m discussing. Once you become insulin resistant, your body responds to carbs by secreting more insulin. So it is quite possible — and laboratory work backs this up — that sugar causes the initial insulin resistance because of the effect of the fructose on the liver. So if we never had sugar, we’d be able to eat the other carbs with relative impunity. But being possible doesn’t mean it’s true. I suspect it is, but I’m not sure exactly how this can be tested.
And I agree with you: the world is full of obese and diabetic people who know enough not to eat sugar, but remain obese and diabetic. I could avoid sugar and go back to eating starches and put on 20 pounds of fat effortlessly. I’ve done it in the past — distant past. So I don’t buy the idea that avoiding sugar is enough to make an obese person lean again. And the people I know who believe that all tend to be somewhat plump despite their beliefs. In fact, I recently heard Dr. Lustig give a talk in San Francisco, and he acknowledged that he still has a weight problem, but doesn’t know what to do about it. Hmmm….
Fat Head: Have you come across any evidence that starches can turn people into fat diabetics without fructose being part of the diet?
Gary Taubes: It’s tricky. Typically consumption of sugar, white flour and starchy vegetables all tend to go hand-in-hand. So it’s hard to tease out this one. I suspect beer could, but I don’t know if even beer drinkers who don’t eat sugar tend to become diabetic or not. What we’d need is a population of white-flour eaters who didn’t eat any sugar at all. If we could find such a thing, naturally, then we’d have some idea.
Fat Head: Dr. William Davis tells his blog readers that wheat seems particularly adept at promoting weight gain. Did you come across anything in your research to support that idea? I know for me, wheat jacks up my blood sugar far beyond what the glycemic index or glycemic load charts would predict.
Gary Taubes: Again, it’s possible since most of us eat wheat as refined flour, and refined flour was historically identified as a dietary evil, linked to obesity, at least. So in a sense we’re talking about the same thing but coming at it from different directions. My problem with singling out wheat is that then you ignore sugar and the other various and sundry foods that can promote weight gain. I certainly hear from enough people telling me how their health problems went away when they gave up wheat and gluten in particular. Although they typically go on to say they also, perhaps a little later in the game, gave up sugar and other refined, easily digestible carbs as well.
Fat Head: In Why We Get Fat, you wrote that some people might have to give up dairy products and nuts to lose weight. Dr. Mike Eades has also mentioned that nuts and cheese seem to inhibit weight loss in some low-carb dieters. What is it about those foods that can stall weight loss? Is it just that they’re so calorically dense, or do they produce a higher insulin response than their low carbohydrate content would suggest?
Gary Taubes: I think the caloric density thing is nonsense. Remember, I’m trying to get every last one of us away from thinking in terms of calories as the variable of interest. What we want to know is whether these foods stimulate insulin secretion, or cause insulin resistance, or have some other effect on the storage of fat in the fat tissue or the oxidation of fatty acids by other tissues in the body. So nuts still have carbs in them, and for some people they might contain too many carbs. Same is true for nut butters.
Dairy products can stimulate insulin secretion beyond what you would expect from the carbohydrate content. I don’t know if this is true of cheese because I’ve never seen data on this, but it is possible. And some cheeses could be better than others — hard cheeses, for instance, may be better than soft cheeses.
Fat Head: You wrote something in Why We Get Fat that I think every frustrated dieter needs to hear: the proper diet will help us become as lean as we can be, but not necessarily as lean as we’d like to be. Once we become fat, is there a limit to how much fat we can lose without starving away our lean tissue? If so, what’s the barrier to mobilizing and burning those last 10 or 20 pounds of excess fat?
Gary Taubes: Simple answer, I don’t know. But it’s obvious that not every woman can have the body of an Angelina Jolie, regardless of how few carbs they eat. And not every man can have the body or the body-fat percentage of, I don’t know, a Matthew McConaughey, one of these actors who’s always taking his shirt off in movies.
That’s for starters. Some of us are wired to have more body fat than others from the get-go. Then I think when we grow up in a carb-rich environment, some degree of chronic damage is done to the way we partition fuel. Maybe our muscle tissue never quite loses its insulin resistance, or our fat tissue remains more insulin sensitive than it would be had we never seen carbs. Maybe our pancreas secretes a little too much insulin.
It’s hard to tell, but the way I describe it is this: if I grew up in a hunter-gatherer environment — and my mother did as well, because there are effects that are passed from mother to child through the uterus — I’d probably weigh around 175 pounds, even as an adult. Had I stopped eating carbs in my late teens, I might naturally weigh about 190 or 200, which was my football weight in high school. The fact that I not only kept eating carbohydrates into my forties but gorged on them during the low-fat, you-can’t-get-fat-if-a-food-doesn’t-have-fat-in-it years of the late 1980s and early 1990s means the best I can do now, even eating virtually no carbs at all, is about 220. And there’s nothing I can do to go lower, short of starving myself. Semi-starving myself doesn’t work. I tried that long ago.
Fat Head: So what’s the message for those people? Lose what you can and focus on being healthy, as opposed to obsessing with squeezing into a size-8 dress?
Gary Taubes: Precisely.
Fat Head: One of the anti-Taubes articles going around the internet claims that we don’t need insulin to store fat, and that insulin is an appetite suppressant. Can we store any significant amount of fat without insulin? If so, why do untreated type 1 diabetics waste away?
Gary Taubes: Short answer, probably not. We don’t need insulin to burn glucose for fuel, but if we don’t have insulin, we don’t store fat.
Fat Head: In Why We Get Fat, you also stated that elevated insulin in the brain suppresses appetite. Since so many obese people have high levels of circulating insulin, why aren’t their appetites suppressed? Is there a difference between the effects of insulin in the brain and insulin in the bloodstream?
Gary Taubes: That’s the key point. A few years ago I was interviewing the director of the Joslin Diabetes Center, and I asked him what the role of insulin was in obesity, and he said its role was to suppress appetite in the brain. And it does. Three researchers at the University of Washington spent 10 to 15 years trying to convince people that insulin had this role. They had injected insulin into the cerebral spinal fluid of primates and it did indeed suppress appetite.
The problem is these people succeeded so well in their crusade that the rest of the community — this guy at the Joslin among them — simply forgot about what insulin does in the body, which is to promote fat accumulation and energy storage. And it makes perfect sense that a hormone that responds to eating will work to store fuel in the body while it also works, secondarily, to tell the brain that fuel is coming in and eating can cease in a bit. That’s the kind of feedback loop you find all over homeostatic systems. But the fundamental issue is that in the body, insulin promotes fat accumulation and that’s where the problem is.
Fat Head: To lose weight, you recommend that we get most of our calories from protein and fat. Some critics of your work point out that all kinds of foods produce a high insulin response after meals, including beef. But when I read your books, it seems obvious that you’re attributing excess fat accumulation to chronically elevated insulin, not the temporary rise after meals. If meat and pasta both raise my insulin after eating, why does pasta lead to higher overall levels of insulin over time, while meat doesn’t?
Gary Taubes: The idea is that pasta is digested far more quickly, and so it leads to higher initial insulin spikes and that these — at least in theory — may in turn result in short-term insulin resistance, and maybe even long-term. Moreover, beef isn’t just protein even though chefs now like to talk about meat and fish being the “protein course” on the reality TV shows like Top Chef — which I now find myself watching habitually once the children finally go to sleep.
Even lean meat is likely to be 50 percent fat by calories, and the fat seems to be the primary determinant of insulin response in mixed meals. This was a result that Jenny Brand Miller in Australia recently published. It was her work that showed a decade ago that you can get substantial insulin secretion from eating lean beef, actually very lean beef. But in 2009 she published an analysis of mixed meals and the message was the more fat, the fewer carbohydrates, the less the insulin secretion. So, as I say over and over, for all intents and purposes carbs are driving insulin levels — the pasta — and fat and protein together, in real foods, are not.
Fat Head: Do you have a sense yet of the response to Why We Get Fat? Is this the book that will catch on with general public, or is it too soon to tell?
Gary Taubes: I think it will catch on, but it will probably take longer than I’d like. It’s doing well, but I’m fighting the “what’s he saying in WWGF that he didn’t say in GCBC” problem, just as with GCBC, media types always wanted to know what was different in that book than in my 2002 article What If It’s All Been A Big Fat Lie? And then, of course, the low-fat diet proponents wanted to reject that article on the basis that it was just Atkins reheated, and so not interesting. Now I’m dealing with the Atkins-reheated-three-times-over problem, and it’s not easy to overcome.
The point I’ve been trying to make is that, yes, this is an old story, but it happens to be the right story. And the way our media works, an old story is an old story, period. Still, I’ve recently been hearing from researchers in the field, some pretty big-name people, who seem to be fans, and I’d never expected it. So I’m getting lecture invitations from universities that would have crucified me in 2003. This is a good sign.
Fat Head: I was mentally exhausted when I finished Fat Head, so I didn’t like it much when people would immediately ask me, “What are you going to do next?” Seems a bit like picking a boxer up off the mat and asking, “Who you got in mind for your next fight?” But since you live a long way from Tennessee and can’t just haul off and smack me, I’m going to ask anyway: Now that this book is finished, what will you be doing next?
Gary Taubes: Well, mental exhaustion seems to be a chronic condition when you never take a vacation, as I don’t, and when you have small children, as I’ve already mentioned. So that’s kind of a given. But I am getting funding from the Robert Wood Johnson Foundation at the moment to write a book about sugar and high fructose corn syrup, and I’m about halfway through the research. I hope to start writing in about a year and hand it in maybe nine months after that. We’ll see how it goes — and how the aforesaid mental exhaustion and small children affect the estimated time of delivery.
Fat Head: Thank you, Gary. It was a long list of questions, and I really appreciate you taking the time to answer them.
For those of you who didn’t know already, Gary also started his own blog, so be sure to check it out.