Making Sense with Sam Harris - #74 — What Should We Eat?

Episode Date: May 6, 2017

Sam Harris speaks with Gary Taubes about his career as a science journalist, the difficulty of studying nutrition and public health scientifically, the growing epidemics of obesity and diabetes, the role of hormones in weight gain, the controversies surrounding his work, and other topics.  If the Making Sense podcast logo in your player is BLACK, you can SUBSCRIBE to gain access to all full-length episodes at samharris.org/subscribe.

Thank you. of the Making Sense podcast, you'll need to subscribe at SamHarris.org. There you'll find our private RSS feed to add to your favorite podcatcher, along with other subscriber-only content. We don't run ads on the podcast, and therefore it's made possible entirely through the support of our subscribers. So if you enjoy what we're doing here, please consider becoming Today I have Gary Taubes. Gary is the author of three fairly recent books on nutrition, Good Calories, Bad Calories, Why We Get Fat, and most recently The Case Against Sugar. He's a former staff writer for Discover and a correspondent for the scientific journal Science. His writing has appeared in the New York Times Magazine, The Atlantic, Esquire. He's been included in numerous Best of anthologies, including the Best of American Science Writing, 2010,

received many awards, and has become fairly controversial for the very strong position he has taken on diet and human health, and the degree to which he has criticized the field of nutrition science. He has the knocks and bruises to show for having courted such controversy, but we had a very interesting conversation, and it's one that may actually influence how you eat and what you feed your kids. And now I bring you Gary Taubes. I am here with Gary Taubes. Gary, thanks for coming on the podcast. Thank you, Sam. Pleasure to be here. So let's start with your background as a journalist. I think many people are familiar

with you, but you have a long background as a science journalist, and you've now focused of late on the science and pseudoscience of nutrition. And you've spent three books on this. You wrote Good Calories, Bad Calories, which was a very large and very well footnoted book. And then you wrote Why We Get Fat and now The Case Against Sugar. And all of these are honing in on the same thesis, essentially, and making it more accessible to readers. These books were born of at least one very controversial article that I think was in the New York Times Magazine. How have you approached your writing career thus far and what's caused you to focus on nutrition to this degree? When I started my journalism career, I started, as you mentioned, as a science writer. My background was in physics, so I was naturally going to focus on physics. And my first two books, my first book, I lived at CERN, the big physics lab outside Geneva,

and was embedded with a research collaboration of physicists who, over the course of the 10 months I was living with them, basically discovered non-existent elementary particles and then realized slowly their mistake. By the time I left to write the book, we're willing to publicly acknowledge that they had screwed up. This led me to obsession and fascination with this question of how to do science right, which is excruciatingly difficult, and how easy it is to get the wrong answer. So I did a series of investigations, both for Discover Magazine, and then my second

book was on this scientific fiasco called fusion, which I always saw as a... I actually wrote it hoping it would be a case study that every young researcher would have to read before they engaged in a research career because it was basically about how making an error of any magnitude could ruin your career in a functioning scientific environment. Just remind me, what was the Cold Fusion scandal? Was it a conscious fraud on some level, or was it just a mistake? I concluded for the most part that it was just a mistake, but it was a mistake that the researchers involved at the University of Utah clearly made up data, which is technically misconduct, it's technically fraud, but the reason they made up the data is because their incorrect discovery was being stolen from them by a physicist down the road at Brigham Young University. Stealing fiction, that's fantastic. an option out on my Cold Fusion book by a now very successful Hollywood director who sees it

as a wonderful comedic story about science. But if you think you've discovered something and you have premature data and then somebody who should know is stealing it from you, then that seems to be compelling evidence that it must be real. But now you don't have enough data to actually publish your own paper. So then what do you do? And what they did was made it up. So technically it was fraud, but they were such idiots on some level that it's even hard to say whether they knew they were doing something wrong when they did that. Crazy story.

So anyway, that led me, I had a lot of friends in the physics community after doing these two books, a lot of physicists who saw me as a kind of investigative journalist that they could point at a subject that smelled suspicious to them and kind of pull the trigger and I would go investigate it. And so several of these physicists suggested in the early 90s that I get into looking at the science and public health because they thought it was terrible. And indeed, it was. Everything I had learned from these brilliant experimental scientists in the 80s that was required, not everything, but most things that they've considered required to do science right and minimize the possibility

that you're fooling yourself is considered kind of luxuries in the field of public health. It's just too hard to do it. It's too expensive to do it. Your systems, human beings living in the real world are so messy. So rather than acknowledge that they can't establish reliable knowledge, what the community kind of did en masse, unconscious decision to just lower the standards that they would use to establish causality, to make statements about what is or is not a healthy diet, which is here I ended up focusing on. So by the late 90s, I was writing these investigations for science, first on this issue of whether salt caused high blood pressure, which seems to be common knowledge and the basis of dietary advice since the 1980s.

And you look at the evidence, it's just not there. Unless God told you personally that salt, I know as soon as I say that I'm stepping into dangerous ground here, but unless God tells you personally that salt caused high blood pressure, you'd never conclude that from the evidence, from the randomized controlled trials. This is really just one of the great scandals of science at this point, that there's still so much confusion about what constitutes a healthy diet. I mean, so like, I just imagine if I went to see a cardiologist today, and I told him that I eat, you know, every day for breakfast, a bowl of oatmeal and drank a glass of orange juice, say, some number of cardiologists, a significant percentage, would say that's great. Some would probably say I'm living on the edge, and I think you would probably say I'm living on the edge. And conversely, if I said I ate a plate of eggs and bacon

every morning, many cardiologists, certainly most, would say that I'm attempting a slow suicide, whereas some would say that is optimal, right? So it's just like, how is it that we're in this situation? I mean, we're getting ready to colonize Mars, and we cannot agree about what would be healthy food to take for the trip. Just, it's a crazy situation. Well, and it's worse than that that because this situation exists in the midst of an unprecedented epidemics of obesity and diabetes, right? So over a third of the population is considered clinically obese. Two-thirds is overweight. Something like almost 10%, almost 1 in 10 Americans are diabetic, which is a disease that was vanishingly rare just 120 years ago.

that was vanishingly rare just 120 years ago. So you would think, right, that beset by these epidemics, there would be, like, we wouldn't be able to cross the street in our neighborhoods without tripping over some scientific committee trying to figure out what we did wrong, what we don't understand about the nature of a healthy diet. And instead, there's this sort of placid acceptance that, well, people just eat poorly and we tell them how to eat. And we've been telling them how to eat for 50 years and nobody listens and everyone goes to McDonald's and Taco Bell and that's the

cause of the epidemic and that's what makes us fat. And yeah, it's a crazy situation. I mean, I've been stuck in the middle of it because I am one of these people who think you'd be healthier if you ate the bacon and eggs. I often describe myself as the kind of person who believes that bacon and butter are health foods. And at least if I'm killing myself, I'll die relatively happy. And at least if I'm killing myself, I'll die relatively happy. Knock on wood. Jesus, I'm talking to you. I evoke God and the fact that I'm superstitious in the first five minutes.

That's all right. If you sneeze, I'll probably say, God bless you. It's deeply wired in the brain. Okay. So, yeah, I've tried to document this. My first book, Good Calories, Bad Calories, the two investigations I did for science, first on salt and blood pressure, and then on this belief that a low-fat diet is a healthy diet,

those led me to that infamous New York Times Magazine cover story, What If It's All Been a Big Fat Lie? And by that point, I was pretty confident that the science of nutrition was, I mean, that it's, as you put it, it's a pseudoscience of nutrition. It's not a functioning science as the scientists that I knew would call it. And so, you know, I spent the next five years of my life investigating and trying to figure out what other mistakes had been made, where the mistakes might have been made, what you have to do to fix it. But then that puts me in the position of being

a journalist saying all the authorities are wrong. And while the doctors, you could go to the different cardiologists, cardiologists in your neighborhood might disagree on what's a healthy diet. The nutrition community, the influential nutritionists, for the most part, all agree. And it's reflected in the public health guidelines. Let's talk about your basic thesis here. So what is your criticism of the current state of conventional wisdom, and what do you actually think is the ground truth of what we now have good reason to believe is healthy to eat? more or less fundamental pillars of all nutrition science regarding a healthy diet, regarding what we should eat on a day-to-day level to be healthy. So the most fundamental is this idea that we get fat because we eat too many calories. The technical terminology for it, because people need a technical terminology when they have

a particularly stupid idea is the energy balance hypothesis or theory of obesity. And you'll see articles, I just downloaded one today that was a working group report from the International Agency for Research on Cancer. And the idea is obesity is an energy balance disorder. You take in more calories than you expend, you get fatter. That's sort of the basis of everything because the nutrition community knows that once you get fatter, as you get more obese, you increase your risk of diabetes and heart disease and cancer and gout and all these other diseases. So if you want to prevent that from happening, if you want to prevent that from happening,

if you want to minimize your risk, the first thing to do is you're supposed to balance your calories into your calories out. And it turns out when you look at the literature, you go back that it's an idea that came out of nutrition science from the 1870s to the 1920s. So modern nutrition science actually dates to the late 1860s when German researchers created devices called calorimeters, room-sized devices that can measure the energy expenditure of humans or animal subjects living in these rooms. So you can measure the energy content of food by burning them and burning the food in what's called a bomb calorimeter. Now you can measure the energy content of food by burning them and burning the food in what's called a bomb

calorimeter. Now you can measure the energy expenditure of humans and dogs and the researchers start doing this around the same time that other researchers are working out the laws of thermodynamics and concluding that the laws of thermodynamics hold for animate as well as inanimate objects. And by the early 1900s, you have a theory of obesity that it's caused by consuming more energy than you expend because that's all the research community could measure. So the idea is that the way foods influence our weight is through their caloric content only. And there's this idea that phrase you've heard, a calorie is a calorie is a calorie.

Because a calorie of protein and a calorie calorie, because a calorie of protein and a calorie of carbohydrates and a calorie of fat all brings the same amount of energy into your body. But the problem is that belief system is technology dependent. If all you can measure is the energy content of food, then you come up with a hypothesis that the energy content of food determines your weight. Beginning around 1920, the science of endocrinology, hormones and hormone-related diseases begins to grow and mature. It's pioneered in Germany and Austria.

And the Germans and Austrians come to this conclusion that clearly obesity has got to be a hormonal regulatory defect. They look at men and women fat and differently, men fat and above the waist, women fat and below the waist. So sex hormones have to be involved, right? When boys and girls go through puberty, Boys lose weight and lose fat and gain muscle. Girls gain fat and gain it in very specific places. You know, there's got to be hormonal control of fat accumulation. But the American scientists who began to dominate the field, first of all, they just didn't understand.

They weren't scientists. They were doctors. They didn't understand endocrinology. They were wedded to this idea that fat people just eat too much. They saw a hormonal explanation for obesity as an excuse for fat people to remain sort of gluttons and sloths. They talked about it. You can see it in the literature and articles in the Journal of the American Medical Association

in 1925 when whoever wrote, I can guarantee whoever wrote that article didn't have a clue what endocrinology was, is arguing that obesity is in a hormonal disorder. And then again, the Germans and Austrians are arguing clearly it's got to be. You cannot explain anything meaningful about obesity by this energy conception. Let me just ask a few questions here to kind of bound just how far reaching your claims are here, because you're not disputing thermodynamics, I assume. No. I got a physics degree. I'm not allowed to. Right. Or you would be far more famous than you are if you were disputing it credibly. So I imagine you would admit that on some level, you gain weight because of a surplus of calories. So for instance, if I were going to eat, you know, 15,000 extra calories

a day, it wouldn't matter if those were extra carb, fat, or protein calories. If I was at that surplus day in, day out, I'm going to just keep gaining weight, right? Yeah. Although actually it might matter. You might, but again, it depends how you define excess. Let's use a metaphor, an analogy to help understand. Let's say instead of thinking in terms of excess weight, we're talking about excess money or wealth instead of obesity. Okay. So now clearly you can't get rich without making more money than you spend, right? But you would never say that you got rich because you made more money than you spent. There are certainly degrees of that disparity and where you put the line is a judgment call, but it's not just a matter of... But also where you

put the causality, because again, to get rich, you have to make more money than you spend. That's a given. Right. You know, the conservation of money, just like, unless you're a counterfeiter, just like there's conservation of energy. So to get fat, it means you're taking in more energy than you're expending. But you might get fat because, for instance, I can give you a drug that makes your fat tissue accumulate fat. What you're saying clearly is that there's more to the story. I'm claiming that as soon as you went to causality, as soon as you say, and again, we'd never do it in any other field. Think about climate. Let's use climate change as an example. Clearly, if the

atmosphere is heating up, it's taking in more energy than it expends, right? Otherwise, it wouldn't heat up. But the question is, why is it taking in more energy than it expends? One possibility is that the sun is heating up. So we're getting more energy from the atmosphere, but we're pretty confident that's not happening. Another possibility might be that we actually have a heat trapping phenomenon going on in the atmosphere, in theory, which I believe, for the most part. And so the fact that the atmosphere is taking in more energy than it expends and it lets out is irrelevant. What we want to know is why is energy being trapped in certain areas of the atmosphere? Why do certain frequencies of light get trapped and not others? Why do

certain molecules trap heat in the atmosphere and not others? And what's the source of those molecules? You could think of it as a heat trapping problem. And then you don't think about how much is going in or out. You don't care about that, even though clearly more is coming in. You know, you could think if you're getting richer, your bank account is accumulating money. Yes. But if I suddenly, again, to take the wealth case, if I suddenly told you that I'm now going to spend 10 times more than I earn, and I'm committed to doing that, you can predict that if I live long enough under this regime, I'm going to go broke. And so you're not disputing that basic picture. There's nothing magical here about the hormones. I think you're saying that the difference between our macronutrients and how they interact with

the endocrine system brings many other variables into play, including things like a person's level of appetite, a person's level of involuntary energy expenditure. There are other things happening, right? Yeah, but you're still thinking in terms of the fat mass being fundamentally controlled by how much people eat and exercise by intake and expenditure. And what I'm saying, so think of, let's use children's growth as an example. Okay. Now we could starve a child. Can't do this as an experiment and stunt its growth. Okay. Clearly happens in famines all the time, but we would never say that the child grows because he eats a lot of food. Having a lot of food available certainly allows growth to happen, but the growth is pretty much food

independent or not protein independent. So different macronutrients have different effects. But if we were talking about growth, so again, we could look at the boys and girls going through puberty as an example. They're both getting bigger, right? They're both getting heavier. So we know they're taking in more calories than they expend because that's what the laws of thermodynamics tell us. But the boys lose fat in a girl and gain muscle and the girls gain fat.

So now the fact that they're taking in more calories than they expend is irrelevant to understanding why the boys lost fat and gained muscle and why the girls gained fat and where the girls gained fat because it doesn't happen everywhere. Right. So there are other examples come to mind. So for instance, you wouldn't say of the growth of cancer tumors that that's best explained by a surplus of calories. Exactly. Okay, so there's more to the story. Not just that there's more to the story, but if you think of, like, you could think of cancer as a caloric energy balance problem, because clearly the tumors are growing. And if you needed to push the analogy, and I've got slides to this effect that I use on talk, you can find examples of, like, benign tumorous masses that weigh 50 pounds. If you needed to push the analogy, and I've got slides to this effect that I use on talk, you can find examples of benign tumorous masses that weigh 50 pounds, 100 pounds. And so still you wouldn't think of it as an energy balance disorder, despite the fact

that whoever had that 50 pound or 100 pound benign mass had to take in enough energy to create the tumor. And if you thought about it as an energy balance disorder, you would not understand the etiology of that mass. Right. So what is the etiology in your view of the obesity epidemic? So what happens in the 60s, remember this is only one of the fundamental pillars, so we still have two more to get to. Endocrinology begins to be understood in the 1920s on some profound level. Insulin is discovered, growth hormone is discovered, other hormones are discovered. It's a German-Austrian occupation. The German-Austrians are arguing that obesity is clearly a hormonal regulatory defect and that discussing in terms of energy balance is meaningless.

Because again, it's like discussing the puberty issue, which was one of the examples they used in the literature. The war comes around, the German-Austrian school evaporates and the lingua franca of medicine switches from German to English. And post-war, the science of obesity is in effect recreated by young nutritionists and doctors at Harvard School of Public Health and elsewhere have no clinical experience with obesity and just embrace this energy balance ideas. Clearly, fat people just eat too much. We know this because I know a fat person and he eats a lot. That's about the depth of the thinking. And by the 1960s,

obesity is considered an eating disorder. And it's studied primarily by psychologists and psychiatrists. The 1960, a couple of researchers in New York create something called the radio immunoassay that allows you to measure hormones in the bloodstream for the first time accurately. One of them later wins the Nobel Prize for the work. And the 1960s see an explosion in the field of endocrinology. 1960, see an explosion in the field of endocrinology. And by 1965, it's clear that fat accumulation in fat cells is primarily regulated by the hormone insulin. And this is conventional wisdom. You could look at biochemistry books and endocrinology textbooks today, and they'll tell you the same thing. So remind people, just what is the role of insulin in regulating fat storage?

So we think of insulin as the hormone that's defective in diabetes. In type 1 diabetes, which is the acute form that usually hits in childhood, your pancreas doesn't secrete enough insulin or doesn't secrete any. And in type 2 diabetes, which is the very common form, 95% of all cases, it associates with excess weight and age. Patients actually begin as what it's called insulin resistant. So their pancreas secretes insulin in response to their diet and the insulin regulate controls their blood sugar, but it doesn't do a good job of it. So they have to secrete more insulin to keep their blood sugar control, and they have elevated levels of insulin in their blood throughout the day. So by 1965, it's clear that insulin not only tells your lean tissue,

your muscle cells, and your organs to take up glucose, carbohydrates that constitute your blood sugar to keep the blood sugar in control. They also tell your fat tissue to take up fat and hold on to fat. So by 1965, insulin is being described, including by the couple that created the radioimmunoassay, and again, Rosalind Yalow, the physicist in the pair, later won the Nobel Prize. Her partner, Solomon Burson, passed away. Yallow and Burson are describing insulin as the most lipogenic hormone, meaning it forms fat, stimulates fat formation. And the more insulin, the more fat you're going to accumulate. And the problem is, to the field in general,

so, well, a few things happen. First of all, working physicians read the medical literature and they say to themselves, look, if insulin stimulates fat formation and we secrete insulin in response to the carbohydrate content of the diet, which we do, what happens if you just don't eat carbohydrates? And in fact, they find out that you happen to lose a lot of weight.

This is the basis, the genesis of the Atkins diet. Atkins was a cardiologist in New York who read that literature and said, gee, it seems to me if I remove the carbs and replace it with fat, so I eat a high-fat diet, bacon double cheeseburgers without the bun, I should lose weight because I'm going to lower insulin. If I lower insulin, I'm going to mobilize fat from my fat tissue. And they write these very best-selling diet books. And the medical community responds. The cardiology community responds.

They're beginning to believe the second pillar of the nutritional wisdom, which is that dietary fat causes heart disease. If dietary fat causes heart disease, Atkins is going to kill more people than Hitler did. That's an extreme example. So this scares them. So not only do they have to sort of beat down Atkins, which they do with a kind of vicious critique in the American Heart Association, excuse me, I guess it was, I forget which journal it was, JAMA or the American Heart Association Journal, but they say that these diets are quack diets, they're fad diets, they will kill people. Are we talking about the 90s now? When is this happening? This is way back in the 60s. But Atkins became very prominent with his books much later than that, right?

No, no, 19. He started to become prominent in New York in the magazine world in the late 1960s. the late 1960s, early 1973 was when he published his book, which is right around the time that this belief that dietary fat caused heart disease was gelling. Oh, that's interesting, because my awareness of Atkins came much later. It seemed like there was a resurgence of interest in his diet some decades after that. Yeah, my piece in 2002 in the New York Times Magazine, which was a kind of seen as an apologia for Atkins. I basically said he might have gotten it right. So that piece in the New York Times Magazine kind of resurrected Atkins or was he humming along this whole time?

He was still around. He was still publishing books. People were still buying the books but yeah my piece more or less resurrected it then prompted michael pollan to then write his books in response to the lunacy of anyone suggesting that all of america should be on something like an atkins diet the uh yeah that was interesting the problem happened, though, the disconnect between what the science, the evidence said, and the way the field embraced that evidence happened in the 1960s and 1970s. Okay, so this is just to keep everyone clear here that you've told us about the first and now second pillar. Remind us what they are, and let's get to the third pillar before I distract you again. This idea that obesity is an energy balance disorder is caused by taking in more calories and expense rather than being a hormonal regulatory disorder where the dysregulation

is caused by what foods you eat rather than how much you eat. So basically, I can feed you foods and the idea is they're easily digestible carbohydrates, refined grains and sugars, and they will work to elevate your insulin levels by two different mechanisms. And once your insulin levels are elevated, you will store fat. And if you're losing calories into your fat cell, because now some of what you're eating is being trapped as fat rather than used for energy, that in turn will make you hungrier and you'll eat more. You may even exercise less. But the primary effect of these foods is to make your fat tissue expand and accumulate calories as fat. Some foods are literally fattening independent of their caloric content, and other foods are literally not fattening independent of caloric

content. Okay, so that's your retort to the first pillar. Yeah, and that's, and I can document, and I have documented again, where this hormonal regulatory disorder hypothesis died literally in 1941 and how the energy balance hypothesis is what the Europeans called the energy conception took over in the US and dominated the field. And then in the 1970s, what's interesting about fields of science create paradigms and paradigms shift when the fields are small and maybe a half dozen individuals can determine what's good science and what's not, sort of what has to be known, what's inconsistent, what experiments have to be done. For instance, in the revolution of molecular biology, it happened in the 1950s.

And it's Francis Crick and James Watson and half a dozen other people who made that revolution happen. And if you remove Francis Crick, you get no understanding of DNA. Then the same thing, theoretical physics, you could remove one, Julian Schwinger, and we don't have a standard model as we have today. In obesity, they had the same half dozen people, these guys just didn't know how to do science. They just weren't very smart. It's like, just like you have bad plumbers, we have bad scientists out there. And these guys dominated the field in 1970s. And they didn't like the idea that a

low-carbohydrate, high-fat diet was a preventive way to prevent or treat obesity because they thought high fat would cause heart disease and they thought fat people get fat because they eat too much. Right. So high fat causes heart disease is the second pillar. Yeah, it's the second pillar. So what they did is they just removed, and again, you could see this in the textbooks and the conference proceedings, they said, because we don't like the implications of the endocrinology, we are going to decide that endocrinology has no influence on obesity. We're just going to kind of remove it from the literature to the point that, you know, two months ago, the New England Journal of Medicine publishes an article on the pathophysiology

of obesity, pathophysiology and mechanisms of obesity, which is a disorder of excess fat accumulation. And there is zero discussion in the article of the hormones and enzymes that actually regulate fat accumulation. It's not considered relevant. So I want to get to how you explain that, but just I don't want to leave the structure of your thesis hanging here. So what's the third pillar? So the third pillar is this idea that we should all eat mostly plant diets. So the second is, again, dietary fat causes heart disease,

and then specifically saturated fat. And saturated fat is associated with, you get the significant part of the saturated fat in our diet comes from animal products. Therefore, animal products cause heart disease. And out of this, we get this idea that we should always mostly plant diets. And populations or individuals that eat mostly plants or all plant-based diets are healthier than people aren't. And that, in turn, is based on this field of observational epidemiology. The Mediterranean diet and all the rest. So what is, well, let's just take the second pillar for a second. How do we know that saturated fat in the diet isn't a problem, isn't a problem generally, and in

particular, isn't the primary source of cardiovascular disease? Well, on one level, you can't know it for sure. So we have to leave that possibility out. Anyway, you can't, all we could say is, is it likely to be a cause of heart disease or not? So, and here's where the epidemiology comes into this as well. Back in the 1960s, researchers in the US primarily were interested in why there's such high levels of heart disease in the US and certain European countries and not others. So what they basically did is said, let's look at these populations and see what they eat.

And what they found was that populations that had high levels of heart disease ate a lot of saturated fat. There's a famous study called the Seven Countries Study done by Ancel Keys at the University of Michigan. And so the populations that ate high levels of saturated fat like the US and the UK had high levels of heart disease and populations that ate high levels of unsaturated fats did not. So Greece, hence the Mediterranean diet and their olive oil. And this is a kind of observational study that the question then becomes, if you see that people in the U.S. eat a lot of saturated fat and have heart disease compared to some other country, does that mean they have heart disease because they eat a lot of saturated fat?

This is a question that, you know, you've got an association between saturated fat consumption and heart disease, but that association holds, logically, it holds no causal information. My mother used to say, what does that have to do with the price of tea in China? You know, which is sort of just because the price of tea in China is going up and heart disease is going up, we don't think there's an association there. You know, we don't think it's causal. Why would we think the saturated fat thing's causal? So the only way to know if the saturated fat association is causal is to do randomized control trials to basically intervene, change people's diets, and see if you tell them to

eat more saturated fat or less saturated fat, well, they have more or less heart disease compared to whatever they replace that diet with. And as it turned out, trial after trial tried to test the saturated fat hypothesis and for the most part failed to confirm it. Just in defense of epidemiology, you could also find a population that is eating just as much saturated fat, or perhaps even more, but isn't eating, in this case, sugar, and see that the correlation breaks down. Has that, in fact, been found as well? Well, and again, that's the kind of issues you have with the level of science.

Remember, I was told to go into this field, public health, because my physicist friends thought the science was terrible. So this famous seven countries study that began to really shift Americans towards eating a Mediterranean diet and eating olive oil and polyunsaturated fats instead of saturated fats, looked at seven countries around the world. So the US and the UK and Greece and Italy and, I don't know, a couple of Scandinavian countries and Japan. I may have gotten that wrong, but that's the gist of it. You know, the interesting thing is there are two countries right in the middle of Europe that eat very high saturated fat diets and have among the highest lifespans in the world,

France and Switzerland. diets and have among the highest lifespans in the world, France and Switzerland. So you could just ask the question instead of picking, for instance, Greece and Italy, had they picked France and Switzerland. So I lived in Geneva for a year. The two national dishes are both cheese dishes, fondue or something horrible called raclette that you got at every cocktail party you went to. Clearly, these people eat very high saturated fat. So depending on what countries you pick, you can get very different

answers. As it turned out, Ancel Keys, the investigator ran that study, didn't pick France and Switzerland, he picked Greece and Italy. This is the problem with those kinds of observational studies. There's a host of problems with those kind of observational studies. I had another cover story in the New York Times Magazine in 2007 making that point, where these studies are basically uninterpretable. So what you get instead are researchers with preconceptions interpreting the answers to fit their preconceptions. the answers to fit their preconceptions. In those two cases, you've picked out societies where I wouldn't expect the sugar consumption to be especially low, certainly not the refined carbohydrate consumption. Actually, in France... Aren't they just eating baguette and chocolate as rapaciously as any people who've ever been born? Well, French sugar consumption is about 100 years behind ours.

So they were always notoriously, not notoriously, but the sugar consumption in France was always about 30, 50% of what ours was. Switzerland, I can't say, but I would assume it's the same or close. In fact, the whole Mediterranean that people talk about, the French paradox is actually a Mediterranean paradox. All these countries, Spain, Italy, Greece, all had relatively high-fat diets. Then as you get into France and Switzerland, you go further north, the fat becomes more saturated and less olive oil based, but they all had relatively low heart disease rates. And when you actually dig into this literature, and I was the first journalist

to really do this, I remember speaking to one British epidemiologist who had come originally from Australia, and he talked to me, he said, you know, Australia had this huge Greek population that emigrated after World War II when Greece was decimated. So they moved to, you know, Australia, they live on lamb chops and Foster's beer and their heart disease risk goes down. And so how do you explain them? The question is, who knows? You've got to do randomized control trials. You cannot establish cause and the only times you can establish causality with epidemiology is when you have a phenomenon like cigarette smoking and lung cancer. So you have exceedingly rare disease in non-smokers and you could compare non-smokers to smokers and you see a 20-fold increased risk

of lung cancer in smokers versus non-smokers. And then the reason we believe it's causal is because you can't think of how to explain it. You can't think of an alternative hypothesis, not that the cigarette industry didn't try, but you can't think of a viable alternative hypothesis other than cigarettes cause lung cancer. And of course, it makes eminent sense that clearly if you're drawing smoke into your lungs, you could imagine that that would cause lung cancer. So it makes biological sense. But these other effects that we've based public health policy on are relatively tiny. They're not 20-fold increased risk. They're not three- or four-fold increased risk. They tend to be 20% increased risk or 50% increased risk. And that's simply, you can imagine all too many things that could explain it.

It seems to me you do make this argument, at least in the background in your books, where you emphasize the correlation between the, I think, what are called the diseases of Western civilization, you know, cardiovascular and peripheral vascular and things like gout, and there's a long list of things that seem to come with when a traditional culture suddenly gains access to, in your case, the smoking gun is refined carbohydrates and especially sugar. So it seems that you are talking about changes in populations where you show up among the Inuit, you see that they're eating nothing but whale blubber or a lot of whale blubber and they have no access to any refined carbohydrates. And they don't exhibit these pathologies until you start giving them bags of Doritos and soda.

And then they have all the pathologies that we notice in Western societies. Isn't that part of your story that you're telling? Yeah, absolutely. So you still, you know, science is about, it's funny, I was a science journalist for, I don't know, 20 years before I got around to reading Claude Bernard's introduction to the study of experimental medicine, which he wrote in 1865. And Bernard said, science is about explaining what we observe. said, science is about explaining what we observe. Ultimately, science is about explaining what we observe. And it's weird. I had never thought about that. But you've got observations, whether in the laboratory or in your particle accelerators or in nature. And everything we're trying to do is explain what the cause of those observations are. Is it some new fundamental particle?

Is it some carcinogen in the water supply? Who knows? So the observation that led to this dietary fat hypothesis is that we had a lot of heart disease in the US. And then the point, what I learned doing my research and what I sort of brought back from obscurity is that while US research were focusing on that, there was a sort of school of British research. The British had an advantage. They had missionary and colonial hospitals scattered all over the world. So research would be trained in the UK or in Europe, and then they would go work in Botswana land or some South Pacific island or Australia

treating Aborigines. And wherever they were, they would document, report this, in effect, epidemic of obesity, diabetes, these Western diseases, hypertension, heart disease, cancer. They would all increase in prevalence and in some cases explode in prevalence as these populations all around the world became westernized. And then the question is, what is it about the Western diet that leads to this explosion of diseases? And this is conventional wisdom. And Michael Pollan, with whom I disagree on sort of two of the three of his, you know, his mantra, eat food, mostly plants, not too much. Yeah, Michael basically builds his argument from the same data, that same observation.

And that's what you have. If you try to explain that, then you're asking the question, what is it that Western diets bring to these populations? So you agree with him that we should eat food, but you're not so sure about the plant part or the not too much part? Yeah, the plants I'm not too sure about and the not too much I think is meaningless. It's based on the assumption that you get fat if you eat too much, but then you can't define what too much is. Except just to go back to thermodynamics for a second, you would agree that whatever macronutrient or food you thought was blameless, let's say, you know, a steak, if I eat 15,000 calories of steak, as impossible as that may be in practice,

I'm going to get fat unless I burn 15,001 calories a day. Well, and so the question is, yeah, and again, we're going to get back, because this is the area that's so fascinating. Let's look at it a different way. Just again, I'm saying you could eat, which isn't going to be difficult, you could eat, say, 2,000 calories of steak a day, plus 1,000 calories of green vegetables, or 3,000 calories. If you'd like to continue listening to this conversation, you'll need to subscribe at SamHarris.org. Green vegetables, 3,000 calories. on the Waking Up app. The Making Sense podcast is ad-free and relies entirely on listener support. And you can subscribe now at samharris.org.