The case for keto

A conversation with science journalist Gary Taubes about why the conventional wisdom about healthy diets is changing

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A couple years ago, in the midst of book-tour madness and too much travel and the accompanying stress, my doctor didn’t like what she saw in my vitals. After some further consultation, she recommended the keto diet — high in fat, almost devoid of carbohydrates — to help me lose weight and get my blood sugar where she wanted it. It worked for me like no diet, no exercise regimen, no other health kick ever has.

So today I’m departing somewhat from the usual fare of The Ink to bring you a conversation with a brilliant and pathbreaking and controversial science journalist named Gary Taubes. Going back almost two decades, Gary is one of the leading voices in America to question the conventional wisdom that fat was the big problem with our diets, and that carbs were totally fine. Drawing on the science, he began to think and argue the reverse — that many Americans would benefit from lower-carb, higher-fat diets. And in the ensuing years, that vision has gained a significantly bigger following.

This is not, to be clear, a diet-advice post. It’s a conversation about an insight that really helped me, and might be helpful to you or someone you know: that so much of the discussion of weight and nutrition in America is based on a victim-blaming paradigm about people eating too much. Taubes loathes that victim-blaming paradigm, and he has waged a years-long campaign to replace it with a paradigm that says: many of us have a mismatch between the chemistry of our bodies, on one hand, and our diet and lifestyle, on the other, and changing what we eat can be a way to become healthier without having to live a life of restriction, guilt, and denial.

But first: There will be no live chat today, because I’m prepping for my interview with Senator Elizabeth Warren, about her newly introduced wealth-tax proposal. I cannot wait to share that one with you.

As always, thank you for being part of The Ink. If you enjoy these posts and want to support this work, consider subscribing:

“I blame the scientists”: a conversation with Gary Taubes

ANAND: You were quite early to the advocacy of low-carbohydrate diets years ago, when it wasn't as popular or as well-known as it is right now. How did you first come to that aspect of health and weight loss?

GARY: I thought of myself as an investigative science journalist, whatever that means. My obsession was with good science and bad science and how hard it is to do science right. And in the late '90s, I stumbled into the nutrition field, truly serendipitously. It turns out that the science there is almost unimaginatively bad, in large part because it doesn't lend itself to experimentation. So you have researchers assuming their hypotheses to be true because it's simply too difficult to do the rigorous experimentation necessary when your subjects are humans. The effects are chronic disease effects that take years and decades to manifest themselves. 

So I had this thought to do a story on obesity, the genesis of the obesity epidemic. And while I was doing that story, I came upon five clinical trials that had been done comparing a low-carb diet, basically the Atkins Diet, to a low-fat, calorie-restricted diet of the kind the American Heart Association was pushing. The findings were conclusive in all five studies. Not only did the subjects eating the high-fat, saturated-fat Atkins Diet have better heart-disease risk factors despite the diet being ad libitum, which means you can eat as much as you want, but they also lost more weight than they did eating the calorie-restricted, low-fat American Heart Association diet.

To me, that was compelling evidence that there was something to this idea that carbohydrates are fattening. And the diets that restrict them can lead to weight loss. 

ANAND: As far as I understand it, the conventional wisdom was carbs are fattening up till the '60s or '70s. Then there was some kind of concerted effort by certain corporate actors that benefit from highly profitable high-carb, high-sugar foods to change the conventional wisdom, much as they did with baby formula. The conventional wisdom changed, and then it started to change again partly because of your article and other writings. Can you give us the history of these phases?

GARY: I don't actually blame the corporate actors. I blame the scientists. For starters, obesity and nutrition research through the 1960s was very limited. So it starts off being about vitamins, minerals, protein, fiber, and, on some level, calories, and that's all they're doing. And they're studying deficiency diseases.

Then there's a shift in the 1950s, with this idea that rather than studying vitamin-deficiency diseases, where you can replace the vitamins and minerals that are deficient and cure the disease, you can test these hypotheses. 

So you've got this sort of very scientifically naïve discipline in which, again, the conventional wisdom is that carbohydrates are fattening. And then it's a piece of nutritional wisdom with which few experts would disagree.

Beginning in the 1950s, you get this hypothesis that dietary fat causes heart disease. You had a belief system that carbohydrates are fattening. And then, you develop a hypothesis that dietary fat causes heart disease. Saturated fat raises cholesterol, which clogs arteries. So you test that hypothesis, so tests are ambiguous. But again, these are bad scientists, so if they get a positive result, that means they're right. If they get a negative result, that means they did the experiment incorrectly. This is the classic bias of every bad scientist.

By the 1970s, you have this sort of social scientific journalist movement to implicate dietary fat in heart disease. And if you want to eat less fat, you have to replace those calories. The protein in our diet typically comes with fat attached. So if you want to minimize fat consumption and reduce fat consumption, you swap those calories for carbohydrates.

By the 1980s, there's now a federal government movement to put the whole country on a low fat, low saturated fat diet. It goes along with a movement, the idea that carbohydrates are heart-healthy diet foods.

ANAND: To step back a little bit, I have an interest in this because I lost about 40 pounds on keto over the last couple years. So I probably know more about this than most people. But can you just go back to basics, assuming zero knowledge, and tell us: what is the keto diet?

GARY: The keto diet is a diet that restricts entirely, for all intents and purposes, sugars, grains, and starchy vegetables and replaces those calories with fat. Simple. More or less the phrase I use in the new book, which I borrow from Brillat-Savarin, more or less rigid abstinence from carbohydrate-rich foods in the diet. And then you replace those calories with fat.

ANAND: Just to break that down a little, the obvious ones that I think most people would intuitively understand: meat good, avocados good, olive oil good. Bread: bad; potatoes: bad; a regular Coke: bad.

GARY: Exactly.

ANAND: Those are the obvious ones. Can you go down some of the not obvious ones in each category? That was what was a little tricky for me. I think a lot of people are surprised by fruit, for example. A lot of people are actually surprised by which vegetables have carbs.

GARY: It's not as simple as it seems. Because everyone's going to be different, everyone's going to be able to tolerate a different level of carbohydrates in their diet. But, yeah, bread is out. Pastries are out. Anything made from flour is out. Pasta's out. Starchy vegetables — so potatoes, sweet potatoes, turnips — probably are out. 

Most fruit is out, because most fruit, despite having a high water content, is not much different than a potato except that the apple has more water and fewer calories per gram. It also has more sugar. So the fruits that are left are very low-sugar, low-carb fruits, particularly berries. Then avocados and olives, which most people don't think of as fruits, but they are.

The nuts are an area of controversy. For most people who go on carb-restricted diets, nuts become their snack of choice. But they're very easy to overeat, which is an issue we have to discuss. Meaning you either consume too many calories from nuts or the carbohydrates in the nuts stimulate too much insulin secretion, because nuts do have more carbohydrates than animal products. 

ANAND: Am I right in saying not all nuts are to be treated equally? Cashews and pistachios are much more problematic than peanuts, for example?

GARY: Yeah. Well, people have issues with peanuts. In my world, somebody has an issue with everything. In general, the better the nut tastes, the more carbohydrates it has in it, with the exception of macadamia nuts and Brazil nuts. Well, Brazil nuts don't taste all that good. 

Most strict practitioners of the ketogenic diets in the medical world will not include nuts on their list of allowed foods because of this. Again, they'll say they don't do it because it's just too easy for people. You go to have half a handful and you end up having two handfuls.

ANAND: I can relate.

GARY: So is that a calorie issue or a carbohydrate issue? I think it's the carbs. Other people think it's the calories.

ANAND: I don't know if it's the keto speaking or the current political situation speaking, but I regularly just have a giant spoon of peanut butter around 2 or 3 p.m. every day. I just want to know if you absolve me of that or not.

GARY: I mean, one of the issues here is, if you're at the weight you're happy with and everything's fine, are the polyunsaturated fats in the peanuts and the peanut butter increasing your risk of heart disease? I know people who believe that. But, simultaneously, I would argue that whatever that increased risk is, it's so trivial as to be ignored. I used to live on nuts. They were my snack of choice. This is the kind of self experimentation that I try to get across in the new book.

I started getting a rash on the side of my face and behind my ears. It would always be worse at night than during the day and in the morning when I'd wake up, so it suggests that it's something I'm doing in the day and something I'm eating. 

So I started eliminating foods, and the first thing I eliminated was the nuts. Well, first I switched from eating 1,000 calories of almonds a day to eating 1,000 calories of macadamia nuts, thinking I'll change the type of fat in the nut. That didn't make any difference. So then I decided I would get rid of the nuts, which means now my snack of choice is pork rinds and butter. I'm convinced I'm killing myself, but it's not obvious other than it can't be good for us to eat pork rinds and butter.

ANAND: Just to be clear, you dip the pork rinds in the butter?

GARY: Well, I cut a very thin slice of Kerrygold butter, and I lay it across the pork rind.


GARY: It's delicious.

ANAND: You're going to start a trend.

GARY: My Jewish ancestors are rolling in their graves as I say this.

ANAND: Yeah. Well, I guess they didn't know about the science at the time.

GARY: Exactly. Anyway, the point is I switched from nuts to pork rinds. It's conceivable that I'm eating fewer calories because it's easier to over-consume nuts than pork rinds. I lost about seven pounds I didn't think I needed to lose, and the rash went away. But I, too, used to have a spoonful of peanut butter before a workout, for instance. Now I don't. I have a piece of butter on a pork rind.

Again, there is some degree of individual variation. What I don't believe there's individual variation about is the fundamental mechanism that you're fixing by going on the ketogenic diet. 

Let me use you as an example. The conventional wisdom is you lost 40 pounds because you finally found a diet that allowed you to eat less. OK?

ANAND: Yeah.

GARY: And for whatever reason, you are eating less on a ketogenic diet because you don't have all that pasta, and bread, and potatoes, and sweets, and sodas, and beer, and all that stuff to consume, so you're eating less. That's why you lose weight, and it's that simple. 

If you say to people, "Well, why isn't Anand hungry all the time if he's eating less?", they'll say, "Well, protein is more satiating and fat is more satiating. And maybe the ketones are inhibiting appetite in his brain." They have all kinds of hypotheses to explain it, none of which have really been tested or make a hell of a lot of biological sense.

The flip side, which I talk about in the book, is that if you look at what regulates fat storage in fat cells, it's the hormone insulin. So insulin dominates, because insulin regulates the uptake of fat into the fat cell, and it inhibits the release of fat out of the fat cell. 

So what happens when you eat a mixed meal and it includes carbohydrates, you stimulate insulin response to the carbs, and the insulin level is prioritizing keeping blood sugar under control. As insulin slowly comes down, you mobilize fat from your fat cells and you burn it for fuel. So in between meals, your insulin levels should drop. And when they get below a certain threshold, you'll start mobilizing fat and burning it and your body will switch from burning carbs to fat. 

If you were insulin resistant, which you almost assuredly were, then your insulin levels pretty much all the time are going to stay above the level, this threshold, that they have to get beneath to allow fat to come out of the fat cells. So if you're insulin resistant, you're basically in fat storage mode all the time. It's the kind of term that diet book doctors use, but it's appropriate, unfortunately.

ANAND: Is that just a fixed property of certain people? Is it genetic?

GARY: The way I think about it is, it's clearly kinetic. You look around the world, you see manifestations of obesity and diabetes epidemics anywhere that a population switches from whatever its traditional diet is to a Western diet and lifestyle. 

It could be carnivores like the Inuits, or the Masai, or the pastoralists in Africa or the Native Americans of the Great Plains. It could be Southeast Asians living primarily on rice and wheat and a little bit of fish and soy. But add a Western diet and lifestyle to whatever that traditional diet is, and you'll see manifestation of obesity and diabetes epidemics.

So geneticists would say that something about the Western environment triggers the obese and diabetic phenotype. But it does it from any underlying genotype.

So the question is, what triggers it? There was a British hypothesis around refined grains and sugars. What I and others brought to this is that they're clearly working primarily through insulin and insulin resistance. So, as a Southeast Asian, you would be particularly susceptible, as are Africans and other South Pacific Islanders, because you had a very low-sugar, low-refined-grain diet until basically the last 100 years. Europeans and Americans had more time to adjust.

ANAND: Interesting. I want to ask you about two things I'm sure you have heard before. One, the expense question, and, two, the climate question. So on the expense side, is this necessarily a more expensive, affluent diet? And is it a diet that's inevitably worse for the planet than the alternative?

GARY: You've got to put this in context. The argument is that carbohydrates are fattening. Those of us who fatten easily, who struggle with our weight and our blood sugar control, do so because we can't tolerate the carbohydrates we eat. And if we want to fix it, we have to remove those carbohydrates. So we don't have an option if we want to be healthy or as healthy as we can be. That's the fundamental context here.

So is it expensive to do so? One argument for why obesity and diabetes is so widespread is because the cheapest calories in the diet are from sugar and white flour. So if you're poor, you're eating the standard American diet and you're getting your calories from sodas, white bread, French fries, beers, and everything else that's carb-rich. It's very inexpensive to do in America and now pretty much worldwide. And if you want to eat a better diet, it's going to cost you more.

Regrettably, animal flesh is the one product food source that doesn't really come with carbohydrates attached. So the easiest way to eat these diets is animal-sourced and cruelty-rich. All you have to do is eat those foods and green leafy vegetables, and you remain on a ketogenic diet. Fish, chicken, some kind of meat, dairy, but not milk, because milk is lactose rich, which is a carbohydrate. That's kind of the catch. 

So, yeah, it's going to be more expensive because these foods are more expensive. And the cheaper these foods are, usually the worse the animals were treated and the worse food the animals were fed, which may or may not make a difference.

ANAND: And the same on climate?

GARY: Yeah, that's the issue with climate also. So if you believe that livestock agriculture is a significant contributor to climate change and one that has to be reduced, then you've got a problem. Now, you can do vegetarian versions of ketogenic diets. You just have to use a lot of vegetable oils. You can do vegan keto. There are Facebook groups dedicated to vegan ketogenic diets. Tens of thousands of people do it, but it's much more difficult to get a well-balanced diet. 

ANAND: That's interesting. Let me just say that back to you and see if I understand it. In a way, the minority of people on actual keto are a proof point that if it works for them, it's telling us something about the way the rest of us eat that could be changed in a less drastic way.

GARY: Right. So the idea is if you're metabolically healthy, which means if you're relatively lean and not insulin-resistant, then if you improve the quality of the carbohydrates you consume and cut back on the sugar and the sugary beverages, then you'll be fine for the rest of your life. 

If you're not metabolically healthy, which in the U.S. unfortunately now means 75 percent of the population, and you want to fix that, just improving the quality of carbohydrates is probably not enough. Now you have to restrict the carbs you eat. You have to replace those calories with mostly fat, and that pushes you towards a more offensive diet that has potentially more adverse consequences for the environment and climate change.

ANAND: I wanted to ask you, given not just this book but your whole career, what do you make of the arguments about combating an obesity epidemic, on one hand, and, on the other hand, the rise of the fat-acceptance movement and criticism of fat shaming and those types of things? How do you see that whole swirl of conversation?

GARY: I say this in the new book: fat shaming is a direct consequence of the belief that obesity is an energy-balance problem — that the reason you ended up 40 pounds overweight is you ate too much. And the reason you couldn't fix it until you went on the ketogenic diet is because you did not have the willpower to eat less. It's a brutal version of it, but at its essence that's what that false hypothesis is.

And then you start attaching numbers. Let's say when you were 16 you were at a healthy weight, and by 35 you had put on 50 excess pounds of fat. So, that's 50 excess pounds over 20 years, that's 25 excess calories a day that you stored in your fat tissue. So that’s one to two bites of food that you ate to excess every day, or that your fat tissue stored to excess every day. And then you have to explain why you wouldn't fix that by just eating less. Right?

ANAND: Yeah.

GARY: Because lean people apparently stay in energy balance effortlessly, so why didn't you if the problem is only 25 calories of fat stored every day in excess? And the answer is you either didn't have the willpower or you didn't care enough.

ANAND: So, like a lot of things in our society, it's based on a victim-blaming paradigm.

GARY: It creates a victim-blaming paradigm. There's no way to accept the energy-balance hypothesis and not blame the victims, although I would argue that most of modern obesity research is an attempt to do that. A lot of modern research is aimed at this. How can we blame obesity on eating too much but not shame the obese person for having eaten too much? Particularly when not eating too much is a question of eating, say, two or five or eight bites of food less every day. So, again, to me, it's profound evidence that their theory is wrong, but they don't think of it that way. 

ANAND: But there’s also this argument that says, who cares about some of these other health complications? It's painful to go through life always feeling bad about being overweight and always trying diets and being frustrated, and we should just accept our bodies the way they are. I wonder how you think about that.

GARY: Well, I completely agree with that. I completely understand it. But it's in part fueled by the fact that people have been told that the way to treat the issues with their bodies is by eating less. And because it doesn't work, it makes them miserable. I have a friend who was 400 pounds at age 18. He had an uncle who was 800 pounds before he went on bariatric surgery. This kid said he never walked away from a meal not being hungry, and he didn't really eat any more than his lean friends. He ate the same crap they ate — pizzas and Cokes and stuff like that, but it's not like he had two pizzas when they had half a pizza.

When he was 18, his father gave him my New York Times Magazine piece. He started basically eating fatty meats, fatty ground meat that his father would buy 30 pounds a week of at Costco, and green vegetables. He lost 130 pounds in four months. For the past five years, he's weighed around 230 pounds. 

He's about 6'4", so that's a healthy weight for him, although he's still a big kid. You couldn't pay him to eat a carbohydrate, and I know that because I tried to get him to do an anabolic experiment for me where he would add carbs back into his diet and keep his calorie consumption fixed, and he refused to do it.

We have a world of people who insist they feel healthier on the ketogenic diet. Doctors who believe their patients are healthier. We have clinical trials that show it's a healthy way to eat. Probably more clinical trials done than any other diet in existence. The American Diabetes Association’s last consensus report on nutritional therapy confirmed that there were more trials of low-carb and very low-carb diets for diabetes than any other diet, and that they were more consistent than any other diet, consistently beneficial. 

And then there's a possibility that if people do this religiously, they will lose significant amounts of weight without being hungry, like you did. It will in effect fix their underlying metabolic disturbance. But if they didn't have to be obese, would they be happy not being obese? The price being they don't eat carbohydrate-rich foods ever again. And I don't know what the answer is. I want to try and get more and more people to experiment with this. Part of writing a book was about getting them to do it right when they did experiment, so that they would know what the tradeoff really was.

Gary Taubes is a science journalist. His latest book, “The Case for Keto: Rethinking Weight Control and the Science and Practice of Low-Carb/High-Fat Eating” is out now. This interview was edited and condensed for clarity.

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Photo: Gary Taubes’ website