in: Health, Health & Fitness, Podcast

• Last updated: March 4, 2022

Podcast #754: A Surprising Theory on Why We Get Fat

There are two dominant theories as to why Westerners have gotten increasingly obese in the last fifty years. One is that we’re eating too many carbs and carbs make us fat. Another is that our primitive appetite — which is wired to gorge on calorically dense foods as a survival mechanism — is misaligned with a modern landscape in which food is available in an overabundance.

My guest today says that there’s too much evidence which contradicts these theories for them to completely explain the problem of weight gain, and forwards a different and quite surprising theory as to what may be going on instead. His name is Mark Schatzker and he’s the author of The End of Craving: Recovering the Lost Wisdom of Eating Well. In order to arrive at Mark’s theory on the rise in obesity, we first unpack several pieces of the puzzle, each fascinating in its own right. We discuss how the body, rather than having a natural propensity to gain weight, actually typically wants to stay at a healthy set point, the difference between wanting and liking and how obese people crave food more but enjoy it less, and why it is that humans take pleasure in eating. We then get to how food additives, like artificial sweeteners, and, strangely enough, even certain vitamins, may be shifting the body’s set point, increasing people’s craving for food, and triggering weight gain. We end our conversation with Mark’s counterintuitive call to fight obesity by thoroughly enjoying truly delicious food.

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Brett McKay: Brett McKay here, and welcome to another edition of The Art of Manliness podcast. Now, there are two dominant theories as to why Westerners have gotten increasingly obese in the last 50 years. One is that we’re eating too many carbs, and carbs make us fat. Another is that our primitive appetite, which is wired to gorge on calorically dense foods as a survival mechanism, is misaligned with a modern landscape in which food is available in an over-abundance. My guest today says that there’s too much evidence which contradicts these theories for them to completely explain the problem of weight gain and forwards a different end quite surprising theory as to what may be going on instead. His name is Mark Schatzker and he’s the author of The End of Craving: Recovering the Lost Wisdom of Eating Well.

In order to arrive at Mark’s theory on the rise in obesity, we first unpack several pieces of the puzzle, each fascinating in its own right. We discuss how the body, rather than having a natural propensity to gain weight, actually typically wants to stay at a healthy set point. The difference between “wanting” and “liking” and how obese people crave more food, but enjoy it less. And why it is that humans take pleasure in eating. We then get into how food additives like artificial sweeteners and, strangely enough, even certain vitamins, may be shifting the body set point, increasing people’s craving food and triggering weight gain. We end our conversation with Mark’s counter-intuitive called the Fight Obesity by Thoroughly Enjoying Truly Delicious Food. After the show’s over, check at our show notes at

Alright, Mark Schatzker, welcome to the show.

Mark Schatzker: Thank you so much for having me.

Brett McKay: So you got a new book out called The End of Craving, where you explore another theory that’s out there now about why Westerners have been gaining weight for the past half century. And this new theory… Well we’ll get to it, but it’s kind of mind-blowing. I’m still in shock about it. So hopefully, you explain it. But before we get to that, this theory you put out in your book, End of Craving, let’s talk about the different theories that are out there right now to explain why Westerners have been gaining weight for the past 50, 60 years. So one idea is that it’s the increased consumption of carbohydrates that’s been driving the increase in obesity. Can you walk through this theory and what does the research say about the carbohydrate-driven idea of obesity?

Mark Schatzker: Yeah. And I think it’s best to understand it in its historical context, and that’s sort of in line with, you might call the… What I call the Wrong Fuel theory of weight gain or kinda like these nutrient wars. So in the 70s, we started fighting this war over fat. In the 80s, I grew up in the 80s, and we were just very conscious of fat, low fat, there’s too much fat, fat makes you fat. And then we had this cultural kind of realization that this was not working, and in the early 90s, and it progressed from there, this idea that we had it all wrong, in fact it was carbohydrates that were causing obesity, and overnight the thing on this really changed. And at first it was kind of a fad diet, this idea that you can eat kind of unlimited bacon and steak and cheese and lose weight. But over time, this gained legitimacy and it became known as the carbohydrate-insulin model, and it has everything to do with insulin. It’s in the name, which is a hormone that regulates energy metabolism.

So basically, when you eat food, the pancreas secretes insulin and fuel. Sugar and fat is taken up into cells, and then as insulin levels drop, this fuel goes back into your bloodstream. The carbohydrate-insulin model says that, when you eat a diet excessively high in carbs, particularly refined carbohydrates, what happens is you get these secretions of insulin that are just too big. And this not only causes blood sugar to drop, it causes fat to be taken up into cells and it inhibits fat from being released and being burned. So what then happens is you have the state of internal starvation. There’s no fat in your bloodstream, there’s no sugar in your bloodstream, so you’re starving. You eat again, what do you eat? You eat more carbs, and the whole thing repeats itself. You get in this vicious cycle of eating, not being satisfied, becoming ravenously, hungry, fatigued, and then you eat again. So that was this kind of insight into where our diet went wrong.

Brett McKay: So that’s the carbohydrate-insulin model. You also, to highlight another idea of why we’ve been gaining weight, you call it the Hungry Ape theory. What’s that theory?

Mark Schatzker: Yes. And to be fair, there’s lots and lots of theories, but I guess this is what I would say is also kind of culturally prevalent at the moment, and that’s my coinage, the Hungry Ape theory. Scientifically, I guess you could say a part of this theory is the Thrifty Gene hypothesis. And that’s the idea that, historically, as we were evolving, starvation or famine, just not getting access to food was a real present danger. So anybody who had the ability to store some extra calories as fat would have an advantage because when these times of starvation or not enough food came around, you could wait it out, you could survive, where somebody who didn’t have that stored fat died. So the idea is that this became baked into our genes, this inclination to store calories as fat.

Brett McKay: Gotcha. So those are, I guess, the two main theories you see out there these days?

Mark Schatzker: Yeah. And I would say the reason I call it The Hungry Ape is because it goes beyond that. There’s this idea now that we’re just sort of… We have this primitive appetite that was molded by evolution that just isn’t suited to the modern world where we’re surrounded by junk food and fast food and potato chips all the time. So it’s kind of like the primitive brain, primitive appetite, ultra-modern world with too many calories and we’re just overwhelmed.

Brett McKay: So there’s research out there that supports both of these models of why we gain weight, but is there any contradictory research out there that shows that maybe these theories don’t explain what’s happening?

Mark Schatzker: So the carbohydrate-insulin model, that became very culturally prevalent, very popular, there’s been different versions of it, there was Paleo-Keto, but they all kind of stem from the same initial thought. And there has been studies done on it, I point to in the book, there’s one that was done by Kevin Hall in which… He’s a researcher at the National Institutes of Health, and he brought people into kind of a hotel laboratory setting, it’s called a metabolic ward, where he could just rigidly control their diet. And he looked to see if there was some kind of a metabolic difference between when people were on a hard carbohydrate diet versus a high fat diet, and what he found was there really wasn’t much of a difference at all. If anything the low fat, high-carb diet had just a tiny, tiny advantage, but it was such a small advantage as to almost be academic. What he found so interesting about that study, was that these two very different fuels were used so similarly by the body. He said it’s almost like, if you could put regular gas in your car and diesel and your car would run exactly the same.

There’s another study I point to called Diet Fits, and that was run by a researcher at Stanford named Christopher Gardner, very well-respected researcher. And this wasn’t done in a lab with a handful of people, this was done with hundreds of people, free living. They were out there in the real world, and some of them were on a healthy low-fat diet, and some of them were on a healthy low-carb diet. And again, the idea was to see, does one of these nutrient specific diets have a particular advantage, a particular affinity? And what he found again, was just like Kevin Hall, that, boy, they looked exactly the same. And it was kind of interesting because people… Roughly the same number of people did really well on either diet, the same number did okay. And oddly, in both groups, there was actually people who gained a tremendous amount of weight on both of these diets. To look at the bar graphs of each diet side by side, they look almost identical. So those are just two studies I point to, but the truth is there’s been lots and lots of studies. This has really been tested and tested vigorously, and the evidence just doesn’t seem to show that the carbohydrate-insulin model holds up.

Brett McKay: Yeah. Some other research I’ve seen done is, people that can… Somehow they’re able… Science is able to study how much carbs we consume as a society, they’re able to figure that out, and it’s decreased in the past 15, 10 years like, significantly. Like, a big reduction. And I think it’s because of that new cultural norm, that carbohydrates make you fat, sugar makes you fat. Even sugar consumption has gone down.

Mark Schatzker: It has. Exactly. It’s amazing, actually, sugar consumption’s gone down, bread consumption took a real hit, you know, we did respond. And funny enough, this also happened in the 80s. When we got freaked out about fat, we started ramping up our carbohydrate intake. Now, what was interesting in the 80s is that even though we were trying not to eat fat, we sort of… Fat consumption state even. But to me, the interesting lesson about all these things is that it doesn’t seem… What we change in our diet, we always find some means of eating more food, and that’s kind of where I see the smoke and the fire, and that’s also kind of more troubling.

Brett McKay: And then in the book, you start off talking about Northern Italy. People in Northern Italy, they eat a diet heavy in carbohydrates, heavy in fatty meats. They love sausage, stuff cooked with milk and cream. And you think, man, they would be fat, but they’re not.

Mark Schatzker: This jumped out of me, I was so stunned, particularly that nobody had really written about this before. Because I mean, let’s just think for a moment, with all the kind of nutrition and stats aside, just think about Italian food. Think about the incredible richness, the culinary richness that Italy has given the world. There’s so many amazingly delicious things you can think of that come from Italy. Pizza, foremost, among them. Lasagna, Risotto, Olive Oil, all the different pastas. The most interesting thing I found… Well, there was a ton, but one of them is that all of Italy is kind of like a culinary power house. It doesn’t matter where you go, but Bologna is considered… Some people consider it sort of the Culinary Heartland of Italy. And they are… They have, what almost appears culturally, like a food obsession in Bologna. There are groups of people that seem almost like religious orders. There’s a group called The Apostles of the Tagliatella. The Tagliatella is this noodle, it kind of looks like Fettucini but it’s fresh. It’s made with eggs. And this is a group, they call themselves The Apostles, it’s like… They sing the praises, they spread the gospel of this noodle. There is another group that… It’s called The Brotherhood of the Tortellino.

So we know Tortellini, that’s the plural, this ring of stuffed pasta. They dress in saffron colored robes and the leader where’s a medallion. They’re absolutely devoted to this… What is fundamentally a blend of refined carbs and fat, and that is what you can say of so much of Northern Italian food. And then some people think, “What you talking about? Italy as the Mediterranean diet.” But that’s not true of the North. In Southern Italy they eat something much closer to a meditation diet, more olive oil, more fish, but they are oddly… There’s more obesity in Southern Italy, they weigh more than the Northerners. The Northerners eat what seems on paper like the worst possible diet because they’re eating the two things we’ve been pretty much convinced are the culprit, fat and carbs. So it just seems like this is a culture super engineered for obesity. Their food is the most delicious in the world, they seem to revel in these artful combinations of carbs in fat, and their rate of obesity is less than 10%, which is mind-blowing. The last time the CDC released statistics for America, it was 42%. That was before the pandemic, we know it’s been increasing, so it’s almost hard to wrap your mind around.

Brett McKay: Okay. Do we know… Do they eat a comparable amount of calories? Are Americans just eating more calories than the Italians?

Mark Schatzker: Yes. We’re eating more calories. I would say they’re eating more delicious calories, but they’re not eating as much of them. And yet these are very… It’s very, very delicious food. So this seems to be contrary to this idea, particularly this kind of hungry ape sort of idea that we’re wired for calories, there’s this idea, we come out of the womb almost addicted to carbs and fat, and we can never really get our fill. What’s going on in Italy suggest that, it doesn’t seem to work that way. At least not there.

Brett McKay: So the idea is like, if food tastes really good, and we’re gonna get to this, if food tastes really good, the idea is well, if it tastes really good, you’re wanna eat more of it, you’re gonna crave it more, so you’ll eat more of it. That doesn’t seem to be happening in Italy.

Mark Schatzker: No, exactly. This idea that deliciousness is our undoing, that the appetite must be curbed, that the pleasures of eating take us to a bad place, that seems to not be true in Italy.

Brett McKay: Okay. So it’s not carbohydrates, it’s not insulin. Maybe there’s something to that, and you don’t discount it completely in the book, maybe there is something to the Hungry Ape theory, but doesn’t explain it completely.

Mark Schatzker: Well, and I’ll tell you… The one thing I’ll say about the Hungry Ape theory, which I think it’s kind of wrong, so it’s important to understand where this comes from. Calories were very important to human evolution, millions of years ago, our brain was about a third the size it is now, and we had a much longer digestive tract so we could… Brains are energy hogs, but that kind of smaller brain meant that we could fuel it with, let’s say, less energy dense food like leaves, roots, those kinds of things. As we evolved a trade-off took place, our brain got bigger and our digestive track got smaller. So we had this big brain that’s this big energy hog. Well that meant that we had to ramp up to a more energy-dense kind of food, so we started eating fatty meat, seeds, fruit. So rich, dense calories became necessary for us. And I think this is the reason people think, oh, we’re kind of wired for calories. But there’s something really important that people don’t consider, which is that as we evolve, as the brain got bigger and we ate this diet that was richer in calories, that gave us the luxury of not eating, it meant we could spend a smaller portion of the day eating, but we had this ability to say, “Okay, I’m gonna stop eating and I’m going to do something else,” and these are all the things that made us human.

We could build structures. We could craft tools. We could craft clothing. We could tell stories. Create myths. So what’s really interesting to me about this is that when you think of our former, more prehistoric selves, it’s like they were more addicted to food, they were eating all day, they were like cows, they spend so much of their time consumed in getting food and eating that food, spending an awful lot of time just chewing food. As we developed and we started eating richer… Food that was Richard calories, that gave us the ability to say, “Okay, I’m gonna not eat, I’m gonna go do other things.” So I think implicit within that is this idea that we’re not gripped by this fixation with food, that we can turn that off and do other things. So to me, that’s kind of the problem with that kind of Thrifty Gene or Hungry Ape theory.

Brett McKay: Gotcha. And then to add to this evidence against the Thrifty Gene theory of why we gain weight, you highlight all this, I think forgotten research and studies that have been done on the human body that shows the human body is actually really good at maintaining a certain weight. And it has these like sophisticated measurement tools all throughout the body, so it doesn’t go too much above or too much below a certain weight. So can you walk us through these studies done by scientists, I think one guy was named Cabanac, and then there’s another guy, Hirsch, that show the human body actually stubbornly fights weight loss and weight gain.

Mark Schatzker: Yeah. This is a fascinating vein of research, it’s amazing to me that this isn’t better known. I think one of the reasons is that once you realize how things really work, you really start to question the whole possibility of these fad diets that we constantly go through, but let me get into it. You mentioned Michel Cabanac. So it started with him with body temperature, and I’ll start there, ’cause I think it’s important. He had this revelation when he was, at a very early point in his career, he was… He’d been doing kind of an experiment on himself, raising his own internal body temperature and he’s really hot, and he had this other subject coming to the lab and he had to scrub out the bathtub and so he scrubbed it out and he was like sweating and he’s hot, and then he turns on the cold water to rinse it out, and it flows over his hand and for a moment, he has decided, he goes, “Oh gosh, that feels wonderful.” And then he realizes that doesn’t make sense because according to the textbooks of the time, water that cold was supposed to feel unpleasant. So the theory at the time was that, whether water felt good or bad all had to do with skin temperature, if it was above skin temperature or below skin temperature, it didn’t feel good, but if it was right around skin temperature, it felt great.

So he had this revelation, and what he realized was that it didn’t have to do a skin temperature, it had to do with the, what he calls the internal milieu, or what’s going on inside. When his body temperature was elevated, cold water felt good. But then he’d then reverse it and dump ice water into the bath and he’d make the subject cold. And then all of a sudden, hot water feels good. So what he found was two important things. One is that there is this internal calculation taking place, that what we crave, what we want can change depending on the internal milieu. And then this other really important idea that, what we need feels good. When we need to cool down, cold water feels good. When we need to warm up, hot water feels good. So then some years after that, he applied this idea to body weight because he thought, you know, this whole… For him, his kind of body weight had always sort of been in sync with what he needed, he ate what he liked, he loved many of the delicacies of France, but he never really thought all that much about what he ate. When he was hungry, he ate. When he wasn’t hungry, he didn’t eat and he’d always kinda weighed around 150 pounds.

So it seemed as though if the brain manages body weight, it was doing a pretty good job in his case. But then there was the case of obesity and he said, “Why would it be that people seem to be eating more than they would need to?” So he did some very interesting experiments. He had one of his colleagues come to the office one day and just gave him a whole bunch of caramel… Toffee candies. And the first… This guy hadn’t eaten since the day before. First toffee tasted great, second toffee tasted great. Eventually they tasted terrible, which is interesting, you think, when something can go from tasting great to tasting terrible. So it seems like something’s going on. So he said, “Well, maybe he just gets kind of bored of the taste.” So then he tried it with sugar water and he found that sugar water too, we get bored of, but there was something important, only if it’s swallowed. So that demonstrated to him that it isn’t just the taste of food that has to do with our appetite, it’s also something happens after. Once it goes into the stomach, something happens. This is called a post-ingestive effect, something that happens after you eat. So then he did a really interesting study with a group of friends, they basically starved themselves. And early on they found, as many dieters find, no problem. The pounds seemed to melt away.

You’d fit into your old clothes, but then he kind of hit this wall, it was so hard to lose weight, and it became this all-consuming ordeal, he would have dreams of gorging on food, he would take his watch off when he went to weigh himself and he was just fighting this war of attrition with ounces, but he finally reached his goal, I think he went from 150 pounds down to 138 pounds, and then he just started eating again, they had this massive feast at a restaurant called [0:19:00.8] ____. And then for the weeks that followed he just ate and he was hungry and he would gorge himself and he came right back up to 150 pounds, and then bang, it stopped. He came back to his old weight, and then it’s like his appetite just lessened and he was himself again. So it’s as though his body wanted to be 150 pounds, and what he called… That is a set point. It’s kind of like body temperature, your body seems to have a preferred weight. Well, he’s not the only one who found that a very important researcher in the history of this area, his name’s Jules Hersch.

He found a similar thing. At Rockefeller University, he had four extremely obese subjects and he had them lose weight by giving them a liquid diet and it worked really well, they lost weight and came to an end and they were released, “You can go home now,” and they all really looked forward to their thinner, happier lives. And they gained it all back. They came right back to where they were. This fueled a very interesting body of research where they found that people when they are overweight or obese, when they lose weight, it’s as though they’re starving their white blood cell count drops, they became anxious, they become depressed, they become sensitive to cold, and they become absolutely gripped by the thought of eating. A very similar to studies in which people actually are starved, it’s like an identical response, even though they’re not nearly in the same kind of depleted state, but they experience it the same way. But interestingly enough, they found it works the other way too, that people are resistant to over-feeding, and this is the big surprise, ’cause everybody thinks, I could eat and eat and eat, my stomach is like an un-fillable pit.

But they find in over-feeding studies… There’s a scientist and Ethan Since he tried to get rodents fat, he couldn’t. If he really force-fed them he could get them fat, but then they’d lose their weight, they would bounce back to setpoint. He tried it with humans, he tried to get college students… You know, college students are always short of money and hungry, couldn’t get them to put on weight. So he had to go to a prison, and it turned out that this being fed these extra calories was so unpleasant that even prisoners would drop out of the study.

And what he found is that they were eating just an incredible amount of calories, 10,000 calories per day, but their weight only increased by 25%, which didn’t seem enough. It seemed that they were burning extra calories, like their metabolism was fighting extra hard to get rid of these calories, and then when that study came to an end, they came back to setpoint. So it was even found… Jules Hersch did a later experiment, when he found it even works that way with obese people, this isn’t just something you find with people who are trim, that they resist weight gain, he found it’s even true of people with obesity. So that really suggests there is some physiological regulation of body weight.

Brett McKay: And you also highlight there’s like a tribe in Africa where the men… They had to get really fat and so they’ll just force-feed themselves for months, they just sit in a hut…

Mark Schatzker: Yes, these are the Masa people of Cameroon and Chad, it is considered a sign of virility for young men to have this buttery rich layer of fat on their body. So some of them, the wealthy ones engage in something called the Guru Walla, where they’ll sit in a little tent all day and just stuff themselves full of sorghum loaf, full of milk, they can only leave to basically milk a cow or go to the bathroom. And this is so difficult, they have to kind of hold their head in a particular position to make sure they don’t vomit. And some of the weight gain is spectacular. There was one, I think, in the course of a single day, he ate the caloric equivalent of more than 30 Big Macs and they put on serious weight, 30 pounds. But amazingly, they lose it all, they achieve this buttery-rich layer of fat, hopefully they find a spouse. But then over time, it just goes away. They want more than anything to be fat, they are unlike us, they crave to be fat, and they can’t their wish is denied by this seeming rule of physiology.

Brett McKay: So let’s talk about people who get obese. So, these guys who noticed like, “Okay, there’s a setpoint.” It sounds like there’s a shift in the setpoint for people who are overweight, do they know what causes that shift?

Mark Schatzker: No, this is the burning question. What is it that causes the body to defend a higher setpoint? I would say this is the most salient question in this area of research, and this is what people are trying to figure out, this is what this book became a hunt for, is what is it that is making us eat more? What is it that is pushing body weight up?

Brett McKay: Okay, so after talking about theories of weight gain and how our body regulates weight gain or weight loss, you take a detour into the science of pleasure and you walk readers through the difference between wanting something and liking something. So what’s the distinction? And how does this difference show up when it comes to our food?

Mark Schatzker: Yeah, that’s great. And the reason I think this is so important, because I mentioned earlier with Michel Cabanac that he found the urges, the urge to get warm when you’re cold or to stay cool when you’re hot, is what propels us to do that is pleasure. He calls it the motor that drives human existence, something, I’m misquoting but it’s something like that, that pleasure is essentially what gets us to do things. So that study in itself, what scientists call hedonics is very interesting, and we probably seen some of those images on TV, like documentaries where they all stick like very thin wires into a rodents brain, into what they call the pleasure center, and they can… You know the rodent will just drop everything and just sit there and wanna be pleasured by these electrical impulses.

So that research was done in the 1950s, and then they subsequently found that there was a neurotransmitter at work, like a brain chemical called dopamine. It’s in what’s called the Limbic System. And dopamine was considered the pleasure chemical, it was like… Yeah, if you could make pleasure this kind of nectar, it was dopamine, it was this chemical that was euphoria that was essentially just feeling good.

So in the 1980s, there was a scientist by the name of Kent Berridge who was an absolute believer in this theory that dopamine was pleasure, and like all scientists, he endeavored to do more research to show that this was true. So what he did was he used drugs to reduce dopamine in rodents, and then he fired sugar water into their mouth, and what he assumed was going to happen if dopamine is pleasure, that that sugar water will lose its ability to be delicious and rodents show this when they’re giving something tasty, they kind of lick their paws or they stick their tongue out, it’s kind of like them going, “Mm-mmm that’s yummy.” So he thought, “Okay, I’m gonna lower dopamine and do that, and lo and behold the mice found that this was yummy. And it’s like… He just assumed he must have made some mistake that’s not how it works. He did it again, the same thing happened. This time he opted for heavier artillery, he lesioned the rats, which is to say he destroyed this dopamine area of the brain, and now they were truly in a kind of utterly beige existence, just utterly listless. Nothing seemed to… Life was just drained of all pleasure.

And he was utterly sure now that firing sugar water into their mouth is going to produce absolutely no effect, and yet amazingly in this incredibly almost morbid condition, it still tasted good, they would still stick their tongue out and lick their paws. He’s like, “What is going on?” So then he decided to do something different. He jacked up dopamine, He revved it up. Well, this time the rats just ate voraciously, they were eating and eating and eating, and yet even that didn’t turn out quite right because as they were gorging themselves, they would make the reverse facial expression as though they were gagging and going, “I can’t stop eating.” But this is absolutely awful, this made absolutely no sense at the time, he had difficulty being recognized as a scientist, people would avoid him at conferences because what he was saying was just so unorthodox that how could it be that dopamine wasn’t pleasure?

But the evidence kept pouring in and even in humans, some treatments for Parkinson’s disease elevate dopamine in the brain, ’cause dopamine is also involved in movement. And what those patients would find is they would do the strangest thing, one of them just on a lark dismantled his fridge, they would do things like play scratch cards, they would want to gamble, they would pester their wives for sex, they would visit prostitutes, they would watch pornography, but they always insisted that there was actually no pleasure taking place that this is something they wanna do, but didn’t enjoy it. And eventually Kent Berridge figured out what was going on.

And it’s that this idea we think of as pleasure actually has two parts, what he calls is wanting, and this is desire, this is kind of like a missile tracking part of the brain that when we see something, we want, it tracks it and we are drawn to it. And then there’s what he calls liking, which is the pleasure impact moment, and that is when the sugar water lands in the rats mouth and they’re both part of the same reward system, but they are independent and they’re not always in sync.

We know this basically because sometimes we want something and don’t like it. But on a more fundamental level, the question he began to ask was maybe it’s possible that though these things work… It’s a system that does work maybe this is where things can kind of come unhinged. And that was the fundamental question he asked, and the first area he looked at wasn’t food, it was actually the most famous example of pleasure gone wrong and that’s drug addiction.

Brett McKay: Right. And so, yeah, there’s a lot of drug addicts, they talk about they want drugs, they have a craving for it, but when they actually do it, they don’t enjoy it like they…

Mark Schatzker: Exactly. And that is what’s so important to recognize about addiction. And so his research really revolutionized our understanding of addiction. Prior to that, one of the main ideas about addiction was that it was because of withdrawal, that because of the horrible experience of withdrawal, people just keep doing drugs, but that didn’t really make sense because people can be… They’ll have gone clean for a decade, and then one day they just get this craving for a drug and they relapse.

The other idea was that drugs get you high, and that’s why people do drugs. But addicts said, “That’s not true, these drugs don’t get me high anymore.” They know better than anybody else that it’s ruining their life, and what they would say is that the theme of addiction was craving, and that’s what Kent Berridge found is looking at brain scans of addicts, they would find that these cues for drugs, a picture of a syringe, say, or of a crack pipe or something, you would get this huge spike of dopamine, which is wanting.

Now, initially Kent Berridge thought, “This has absolutely nothing to do with food.” And this is important because a lot of people talk about food addiction, we talk as though food is just like drugs, but there’s something that drugs do that food doesn’t do, is drugs get beyond the blood brain barrier and really tinker with these neurotransmitters that are involved in what we call reward, they’re just getting right into the machinery and messing stuff up.

Food doesn’t do that, we experience food when we sense it, when we taste it, when we smell it. So for that reason, he thought food is very different, but then he became convinced when he saw some research looking at people with binge eating disorder, and he found that it was very similar to the people who struggled with drug addiction, which is to say they had this incredible desire that seemed disconnected from the actual pleasure that they would experience.

And this is something that we learn about obesity as well. The stigma about people with obesity is that they’re just pleasure seekers, that they indulge themselves, they don’t know when to say no. But the neuroscience shows us that that’s not what’s going on compared to trim people, they actually seem to experience less pleasure from food, what really distinguishes the experience of food for them is the craving for it. So if they see a picture of a milkshake, the Milkshake, it just absolutely animates them with a craving, they want that milkshake, when they actually taste it, the pleasure they receive doesn’t come anywhere close to matching that incredible desire they had for it.

Brett McKay: We’re gonna take a quick break for a word from our sponsors.

And now back to the show. We’re getting closer and closer to this idea of your theory of what’s causing people to gain weight, so I can understand why we’d wanna crave food, why we wanna want food. Say your body is like, “You need to eat something or you’re going to starve.” So you have the desire. You would think it wouldn’t really matter what food taste like as long as it has calories, that should be fine. You give the example of a snake, a snake actually doesn’t taste anything, it just swallows the rat whole and it gets its calories and it’s done because it has that craving for calories the body saying, “You need food.” Humans can taste. Why do we even experience pleasure when we eat? If all you need is that craving, if your body can send out a signal, “Okay, you’re depleting on calories, go consume something,” and then craving, satisfied. Why do we even experience pleasure in the first place, when we eat?

Mark Schatzker: That became one of the most interesting questions to me because what Kent Berridge found was that that there’s this other part of the brain, this liking part that doesn’t run on dopamine, it runs on opioids, which is like what’s in heroin. And I assumed that all animals have this, right? You want food and then you like it. But it turns out in this respect, humans are abnormal, most creatures out there in the world, they just run on dopamine, it’s a much more simple system, it’s a little bit like a thermostat, that when something goes off, let’s say, “Body temperature is too low.” So you experience the desire to go and return body temperature to normal, when it gets back to normal, the desire turns off.

The same thing with food, it’s like my fat stores or my blood sugar levels are down, so there’s this signal, “Okay, go get food.” You have this desire for food until you’re back to where you need to be, the system turns off. That’s how your thermostat works, in the winter if the room temperature gets too low, a signal sent to the furnace turn on, and then until it comes back up to room temperature, the desired temperature, that’s when it shuts off. Now, interestingly, your furnace works perfectly well without it ever going like, “Ah, that feels wonderful.”

And that’s the same, it turns out with snakes. Snakes have a system that runs on dopamine, so far as we know, they are unable to experience what we think of as pleasure, they can’t even taste food. You can scent a tennis ball to smell like a rat, and the snake will eat it because it is just consumed by the hunt for food. But actually eating food, what we think of as this gustatory delight is for them kinda like maybe what swallowing food is like for us just this sort of necessary mechanical physical act.

Now, it almost seems cruelly like, Why would God… If there is a God, why would God create a creature that is unable to enjoy its food? But it turns out this is the norm, this capacity to enjoy seems to be unusual. So then you scratch your head and you’re like, “Well, why is that? Why do we enjoy food?” If a snake can get by with just on this dopamine system of wanting something and then having that urge go away, that urge kinda being satisfied without ever experiencing delight. What is the point of experiencing delight if it’s not necessary for a snake? Why is it necessary for us? So on its most simple level, the capacity to enjoy something is kind of a quality control system when we get what we’re after, let’s say it’s an apple or it’s an animal that we kill, we can bite into it and see if it’s any good.

That is this system that we have that lets us rate the quality of food as we eat it. We think of it as enjoyment, but what it really is, this kind of instantaneous computation that you feel, this is your brain analyzing the food going, is this good?

Brett McKay: Yeah, you do that when you bite into something, you can taste if it’s savory, if it’s fatty, if it’s sweet. And by tasting that, you get an idea like what you’re about to get like your body is like, “Okay, you’re gonna get some fats, you’re gonna get some carbs, this is good, eat more.

Mark Schatzker: And it’s really important because we tend to think of the sensed qualities of food sweetness, savoriness, fattiness as just sort of like this sort of delight that is unconnected to nutrition, but it’s actually really important because there’s a fundamental difference between how our bodies work and how machines work. So if you’ve ever seen like a fighter jet when it’s refueling in the air, it flies up to this big plane and this tube comes out and it refuels. We can’t do that. Try and eat a pizza while you’re running around a track, good luck with that. It turns out that food is like a disruption to the body, so we really have to be ready for it, and one way we do that is by sensing it as it comes in, even before we taste food, we can smell it, this triggers something called the cephalic phase, we start to secrete insulin. Then as we taste it that gets the gastric juices flowing. What your brain is doing is getting ready to digest, this is a big deal. So that it turns out that is really important information.

Brett McKay: No, you even give an example of a kid. I think it was like in 1800’s, he had something happened to his stomach and he basically… Or his throat, his throat.

Mark Schatzker: Oh yeah, what he did… This is a crazy story. I don’t know how he did it, he was having clam chowder that was somehow way, way, way too hot. I guess he must have just chugged it or something. But he ended up sealing his throat shut, it was like cauterized or something, and he was unable to swallow. So doctors essentially put what’s called a fistula in his stomach. They just put a hole in his stomach that he could just sort of load food into the way you would load your luggage into the back of a trunk of a car.

And when he started to do it this way… When they created this opening, he would put food in, he was very unwell. Even though food was getting in to his body, he was just unwell. It was utterly unnecessary for him to put food in his mouth at this point because he had this direct pathway right into his stomach. But one day he said, “Let me taste it first.” And this is what cured him, he was scrawny and maybe going to die, and then once he tasted his food, he suddenly sprang back to health. And for the rest of his life, he would taste food, he would chew it up and then spit it into this tube that went into his stomach. And he said if he didn’t do that, he would be hungry after he ate. So this is really interesting evidence that this act of eating, this act of sensing food, it isn’t just this kind of de-life as disconnected from metabolism. It is absolutely essential to it.

Brett McKay: Okay. So, when you eat something, when you taste something in your mouth, you’re getting information about this food, now this is the case… We’re getting to the point you’re making in your book, your big thesis, you’re making the case that one of the problems with food today in the West is that there’s a mismatch between that information that we taste and then the actual food, like the calories or the nutrients in the food.

Mark Schatzker: Yes.

Brett McKay: So yeah, talk… What’s happening with our modern food, so that the nutritive information, how it tastes thing, no longer matches the actual nutrition content of the food?

Mark Schatzker: Okay, yes. So remember what I was saying earlier that we find that the difference we see with people with obesity is that they have this enhanced level of wanting. Well, that’s what we’re looking for. What is the thing that’s making us desire to eat food that seems disconnected from our physiological need? What is making the brain say, “I wanna eat more food?” So I came across a body of research from a scientist I know at Yale, her name is Dana Small, and she was asking what she thought was a fairly simple question, which was, “Whether or not you could change the caloric content of a sweet beverage and still have it be satisfying.” She was doing this work at a time with Pepsi, and on a deeper level, she was curious, “Do we like sweet things because we just like sweetness, like that’s how we come out of the womb and sweet is great, or is our desire to eat sweet things connected to our physiological need for it?”

So that’s a really hard thing to test with just a normal sweet drink because you don’t know, is it the calories or the sweetness, like when you put sugar and you’re adding both sweetness and calories, how do you disentangle the sweetness from the calories? It seems impossible. But she came up with a really interesting method, what she did was she created five drinks that were all sweetened with the artificial sweetener called Sucralose, so these are five distinctly flavored drinks, but they all have the same level of sweetness. Then she added a flavorless carbohydrate called Maltodextrin, it was invented in the 1960s. It’s this kind of interesting human creation, carbohydrate with absolutely no taste. So then she put no Maltodextrin in one drink; I think she put 37 and a half in the next; 75; 112; and then 150.

So what she has is this little fleet of drinks, they are all equally sweet, but they all have a different amount of calories. She would have people drink the drinks and then he would come in to get their brain scan and she would look for the response in this dopamine area, which is to say which one of these drinks made them go, I want more of that, and she thought it’s gonna be the 150 calorie drink, because we know there’s this post ingestive thing that happens where the brain analyzes the food that have got… So she said, Well, it’s gonna be the 150 calorie drink ’cause we like calories, calories are important. And that’s not what happened. She was really surprised by what happened, it turned out it was the 75 calorie drink that got the biggest brain response and that didn’t make sense, She was so weirded out by it she did it, the experiment again, and the same thing happened.

And she’s trying to figure out what’s going on. If it’s calories that we like, 150 calories should be better than 75, but if calories have nothing to do with it, why 75? Why not zero? Why not 37? And then she realized it was the number 75, the drinks that people responded to had 75 calories of maltodextrin, but it also tasted as though it had 75 calories worth of sugar and the interesting thing about Maltodextrin is it’s converted to sugar as soon as it gets to the stomach by enzymes, so this drink she found was matched, which is to say its sweetness was in sync with the calories that had delivered. Something funny was going on with these other drinks, she created these drinks that were mismatched, had either too little or too many calories or relative to the sweet taste. So the next thing she did is she put test subjects in what’s called an indirect calorimeter, and this measures the thermic effect of food, which is to say that when you eat food, you start to burn calories and there’s this kind of elevation and body heat that they can detect kind of like how your car gets hot when the engine have been running. So this test subject came in and had the 75 calorie drink, and there was this little plume of body heat, they come in a few days later and they have this drink that tastes like it has 70 calories, but actually has 150 calories.

She’s thinking it’s gonna be this nice big plume, 150 calories. Nothing happens. The metabolic responses, she put it is flat, and this is a really, really important exercise because it shows us just how important sensing what’s in your food is, it turns out that sweetness isn’t just this kind of like thing that we like, it’s operating instructions, it’s telling the body this is how many calories to expect, and that just sends off this cascade of metabolism when it works, when it’s all in sync. When you drink a MASH drink, everything goes smoothly. When it’s mismatched, things go wrong, it’s like the brain’s like, I don’t know what’s going on, and it doesn’t end up getting metabolized, these calories just seemed to flow around the blood that they think it kind of winds up in the liver. She did more studies and she found that this causes insulin sensitivity, what we think of as a condition of diabetes, and they did a study in adolescents, and this is important because adolescents have kind of an outsized appetite for sweet things is… ’cause their brain is growing, that’s why a lot of adolescents drink a lot of soft drinks, and early on the experiment, they tested the blood of three subjects and they were already pre-diabetic, the results were so bad.

They had to stop the experiment. So this to me is really, really interesting, we see some serious smoke happening that when we start, we know how important it is for us to sense food. In fact, I’ll even add something to that, our ability to sense, we do it with the nose and mouth, that takes up more DNA than any bodily system, that’s how important it is. And now we see that when you create food where there’s this gulf between what it tastes like and what’s actually arriving in the stomach, we see problems happening, so already we see that that food isn’t getting metabolized properly, but then you ask a deeper question, ’cause remember how earlier I said that the brain keeps track of everything? That as Michel Cabanac found, you actually have to swallow sugar, water, for it to satiate your appetite, that it’s… What we’ve actually found is the brain is such a kind of obsessive accountant, it doesn’t just measure what happens when that sugar gets in the stomach, it measures to see if sugar is utilized, you can knock a glucose metabolism, you can block it from happening, and when you do that to rodents, sweet things lose their allures.

The brain is like this paranoid accountant, wants to make sure the food it got is actually useful. So you can then say, if the brain is keeping track of things, what happens when one day sweet equals energy, and the next day sweet equals not so much energy or maybe more energy than I expected. This never happened historically, sweetness was always matched, a sweeter strawberry had more sugar than a tart strawberry, a sweeter apple, and so forth. It is only very recently that we have been able to create this difference between how food tastes and what you get, and what that is called is uncertainty, Psychologists also call it reward prediction error, which is to say a lot of psychologists think of the brain as kind of a prediction engine, what it’s really in the business of is predicting, that’s why it senses, the brain senses what it got. Did I get what I was expecting to get. And there’s really interesting areas of research that look at this idea of uncertainty, one of them is reinforcement psychology, so that’s like Ivan Pavlov, that’s when you ring the bell and the dog thinks dinner is coming, it starts to drool. That’s what’s called a cue. So are you familiar with Pavlov?

Brett McKay: Of course.

Mark Schatzker: That’s kind of common knowledge.

Brett McKay: Yeah, it’s common knowledge. Yeah.

Mark Schatzker: Okay. So the bell is what they call a cue, you ring the bell, the dog starts drooling up things, dinners coming, scientists always thought that the more in sync that bell is with the food, the stronger the cue it is, the more reinforcing it is that if the bell sometimes means dinner. It’s like, Ah, I might drool a bit, but if it reliably means dinner that dog is gonna drool. Well, we found that’s not true, it turns out, and this was some really interesting research done with rodents, the cue they would use was a little lever that was illuminated, and it turns out that if you would illuminate this lever, sometimes the rats would push it, but then a little food pellet appears, it turns out that if you actually make it such that the lever might predict food, you’d figure the rest would be like, Oh, who has time for the stupid lever, I’m gonna go over to the food train just wait for the lever, wait for the pellet to drop. That’s not what happens when the cue becomes uncertain, the rats become obsessed with the lever that they’re really, really interested in the lever, it turns out that making a cue uncertain ramps up motivation.

And there’s a very good reason for it. There’s a very good reason we are animated by uncertainty because in a state of nature, a loss means you might die, it means something bad could happen, and I’ll give you an example, a lot of people find this sort of conceptually interesting, but it doesn’t really… They don’t really feel it. So this is an interesting way that really makes you feel it. Let’s say, do you have a car?

Brett McKay: I do.

Mark Schatzker: Okay, so what if I told you the fuel gauge was totally unreliable, that it says full, but it might be empty, it might be a quarter. It might be three quarters. What would you do?

Brett McKay: I’d be filling it up all the time ’cause I wouldn’t…

Mark Schatzker: That’s right, because if you’re on the highway and you run out of gas, you’re screwed… That’s a horrible problem. You probably fill it up almost kind of in a paranoid way, right, there’s this uncertainty and it just animates us with desire. A good example are elevator buttons. When you’re waiting for the elevator, what do you do? When you get on the elevator and you press the 11 button, you just press it once because you know it’s gonna take you to the 11th floor, but when you’re sitting there, waiting for the elevator button, you just channel… You just keep on hammering the thing because there’s this idea… I don’t know if it’s working, I don’t know what’s going on. You are animated at that moment by wanting. So to bring this back to this research that Dana Small did, when we start to tinker with the sensed qualities of food, we take a cue that for all of existence, of our existence as a species even prior to our existence as a species, we’re going way back to cockroaches and bacteria, sweetness has always matched calories.

Very recently, we created technology such that the way something tastes doesn’t necessarily match what you’re getting, so we have created uncertainty, we have these cues for food have now become uncertain, so what does that make us do? It makes us want. That’s why we see it’s not that food taste better than it ever did, I’d argue that it doesn’t taste as good, it’s that we want it more because we want to avoid a loss.

Brett McKay: So, just to summarize, all of our food, a lot of… Mostly processed food, a lot of it has artificial sweeteners, if you check the ingredients, it could be a cookie, a lot of companies are putting artificial sweeteners in it because it allows them to make the food taste sweeter without adding in calories. So what you’re saying is by creating that mismatch, the body is like, “Wait a minute, it tastes sweet, but we’re not getting the calories that we think you should be getting,” some sort of state, so we’re gonna eat more ’cause we don’t know.

Mark Schatzker: Exactly, yeah.

Brett McKay: Okay.

Mark Schatzker: If you think your brain is stupid and we just sort of have this dumb desire for sweetness, then this would be a good idea for your brain, your brain is a total moron. If it turns out your brain is actually this kind of maniacal obsessive accountant, don’t try and fool it because you’re gonna piss it off and you’re gonna make it want more. So that’s exactly what we see. And ironically, it’s probably our fear of calories that are feeling this in some ways, we now have all these nutritional info panels on things, people can look and they go, “Oh, calories, those are bad.” So there’s all these incentives now for companies to lower the calorie count. One way they do that is by adding artificial sweeteners. And it’s more disturbing, I would say than ever, because what Dana Small found is when you mix real sugars with artificial sweeteners, that’s when the worst things seem to happen and we’re doing that more than ever, and it’s not just like soft drinks, you see it in some cold coffee beverages, you see it in energy drinks, you see it in English muffins, I’ve seen it in breakfast cereals, it’s happening everywhere.

But here’s the important thing, my argument here isn’t just that it’s artificial sweeteners, artificial sweeteners, this research is showing us where things have gone wrong, but if you actually start to look for ways we’ve devised of messing up the way food tastes, it’s all over the supermarket.

Brett McKay: Well, yeah, you talk about this artificial fats that the food industry, you say tries to keep under wraps ’cause no one wants to talk about artificial fats.

Mark Schatzker: Yes. So this was another really interesting thing I found. And I was surprised that there hasn’t been more written about it, there’s a whole huge family of food additives. I call them artificial fats ’cause they’re kind of like the fat version of an artificial sweetener, the industry calls them fat replacers, which sounds a little more innocuous, but essentially these are substances that create the sensation of rich fatty food in the mouth, but deliver fewer calories. They are essentially the fat equivalent of an artificial sweetener. One of the first ones was called Simplesse, it was discovered in 1979, a scientist working for a Canadian beer company tried to turn away, where is that liquid that’s left over when you make cheese. He tried to turn it into a gel, and he got this weird gel in the substance that it kind of crumbled like styrofoam, but it tasted fatty, it tasted like cheese cake or like cream cheese. About a decade later, it comes on the market as something called Simplesse and centrally, amazing, it could take the calories and a table to spin a margin from 36 calories down to eight calories, could take a coffee creamer from 30 calories down to 20 calories.

Seems really good, right? What a great thing. We’re lowering the calories, but if your body is counting your brain’s going, “Hold on a second, you’re starting to mess with me now, fat doesn’t mean what I thought it meant.” These fat replacers are all over the food environment, they’re not just in things like low fat dressings, they’re everywhere, if you know what to look for, but here’s what kind of makes them insidious, you’ll never see the word fat replacer or artificial fat. You won’t even see that word Simplesse, it’s really weird. In the industry, they have all these really cheesy names like Simplesse or Likadex, or Keltrol, those don’t appear on the ingredient label, you’ll see things like milk protein or whey protein concentrate, there’s one… There’s a federal placer from muffins, which is called Cream fiber 7000, that shows up on the ingredient panel as citrus fiber, which to me sounds healthy, that’s like, wow, that’s good for my microbiome or something, so it’s really difficult to know when the sensed properties of fat are being toyed with by food manufacturers, you almost have to have a PhD, even then, I would say you can’t really tell by looking at the ingredient panel.

Brett McKay: Okay. So I think people listening to this think, “Okay, that makes sense,” artificial sweeteners, artificial fats, would mess up our brains calculation going on, so to create that uncertainty, so it tastes like we’re getting calories but we’re not, and so our brain to compensate for that craves more food, so that would increase craving.

Mark Schatzker: And I think it’s important ’cause this is a recent change, we’re trying to figure out what change… ’cause it’s relatively recent. Like if you look at obesity, it really took off in the mid-70s, so that is something that’s recent, you can talk about carbs, you can talk about fat, we’ve been eating those for millennia. This is new, this is an aspect of eating that just didn’t exist until like a handful of decades ago.

Brett McKay: Okay, let’s talk about the thing that blew my mind, so one way that food has changed and you make the case that might be construed to our increase in weight gain is the addition or fortifying flour with vitamins, and this started in the early 20th century in America, to cure disease, basically, a lot of people were getting diseases ’cause they… Then bring in efficient vitamins, it’s been fortified, flour, bread with vitamins. You look at Wonder bread, right? The label says that was the big selling point, fortified with vitamins. How is it that something good for us like vitamins might be contributing to weight gain?

Mark Schatzker: Yeah, this is… And let me just say off the bat how absolutely crazy this sounds and I struggled with this, I thought am I nuts? Vitamins? Are you serious? It’s like saying rain causes obesity or oxygen or something like come on, but I’ll tell you how I came to this. The first time I got… The first time I got interested in this was the first book I published was about steak, travel the world eating steak, looking for the best stake. But one thing I got interested in was keeping cattle and feed lots, whereas a lot of us know, we read Michael Paul and they’re fed this diet of corn, and the idea I was always told at the time from critics was that it’s like junk food, it’s just empty calories. Doesn’t have their vitamins. It’s only got calories. And one of the reasons they eat so much of it is they’re trying to get their vitamins, they’re like… They’re unfulfilled by it. So I check with the feedlot nutritionist, someone who actually who devises these things, and he said, “No, that’s not true at all,” he says, “These things are absolutely packed with vitamins, if they weren’t, they wouldn’t gain weight quickly enough.” I thought, “That’s not really what we think.” We tend to think of vitamins is making things healthier, not that they could somehow play a role in a diet that is engineered to make a cow fat.

Well, then I found a researcher, a scientist at the University of Toronto used to be the chair of the nutrition department, his name is Harvey Anderson. He had the same idea, he was interested in the difference, between Canada and the United States, ’cause very, culturally, very similar countries. We have very similar food traditions, Canadians are a little bit thinner. Now, like Americans, we enrich our flour, but we don’t do what’s called voluntary fortification that’s allowed in the States where companies can just put in certain vitamins if they want to, so there’s more of this happening in the United States, it’s been, like I said, being put in energy drinks, it’s in cereals, there’s just an awful lot of vitamins. What I’m most particularly interested, it’s not all vitamins or micro-nutrients that I have a beef with. We add iodine to salt. I don’t think that’s a problem. I think there’s a case to be made for adding folic acid, it’s the B vitamins, it’s the vitamins we started adding in the 1940s, and I’ll tell you why I really started to think there’s something going on here.

I was thinking about this feed lot diet that cattle eat, and I got interested in pig nutrition because pigs are more like us than cows, pigs are… They’re very similar to us, physiologically, a much better model than a cow, and I thought, there’s gotta be something going on with pigs, and I would keep on searching for it and nothing ever came up. Finally, Google Scholar, the search algorithm has got tight enough, I finally found this body of research, and it turns out that vitamins utterly changed pig farming. Before the 1950s, farmers knew that you could give pigs corn and soy, that it was kind of like rocket fuel, gonna make them fat, but only for a limited period of time, if that’s all they ate, they would actually get a nutritional deficiency, they would lose their hair, they’d get diarrhea, they’d start to get confused and they’d lose weight. So there was something missing from the diet, so to make that up, they would have to put pigs out on pasture or if they were keeping them in a barn or something, they’d have to bring green feed to them, so they knew that there was something…

You know what they would often feed them is alfalfa. They knew there was something necessary in alfalfa, that was making their diet complete. The discovery of vitamins totally changed pig farming. All of a sudden, it wasn’t necessary anymore for your pigs to be out there in the field munching alfalfa. You could keep them penned up all day. You could give them this rocket fuel diet of corn and soy, and it was just… They were like a rocketship. They gained weight and put on fat like they never did before. I found a really interesting document put out… I think it was the University of Illinois. Where it was around the 1950s, that basically extolling that there’s a new way to farm. They said pigs have a reasonable ability to manage their diet, but it’s no longer necessary for them to get their micro-nutrients from green feed. You can now give them vitamins. So, this was the new way of doing it, and it gave them what’s called “optimal weight gain.” There was a really interesting study I looked at where they compared pigs that were kept penned up eating this, what they call, a mixed ration, that had everything in there with the vitamins.

Versus they had pigs that were out there in the field, and they had corn in one trough. And then, they had the soybeans, the vitamins, in the other trough. And then, they had alfalfa. And what they found is those pigs out there in the field, somehow when those vitamins weren’t put in there with the corn, they had this desire to eat alfalfa. They ate much more alfalfa. If you added the vitamins to their feed, they didn’t eat nearly as much alfalfa. But the ones that gained the most were the ones that were kept penned up with this fortified rocket fuel feed, and that was optimal weight gain. And that changed pig farming forever. That’s why we have these flesh factories where we keep pigs in kind of factory-like conditions, where we just jack them up full of corn, soy, and the vitamins necessary to metabolize that feed. That’s how we invented factory-farming. Vitamins played a huge role in that. So, oddly enough, what was such an important ingredient in making pigs gain weight optimally is what we’ve been doing to our food for more than a century, and we’re doing more and more of it.

Brett McKay: What is it about B-vitamins that causes weight gain? What’s going on there, do we have an idea?

Mark Schatzker: It’s because they’re the energy metabolizing vitamins. They are the ones that make energy metabolism possible. If a diet is deficient in one of these vitamins, you die. So, this is where one of these insights came from is… A little over a century ago, both the American South and Northern Italy were suffering from an epidemic called Pellagra, just like the epidemic we’re going through. Initially, people didn’t know what was going on. There was all these… There was a shouting match of experts who knew just what the problem was. It turned out that it was a deficiency of niacin, which is vitamin B3. Very interestingly, America took kind of this new scientific road.

That’s when we decided we’re going to enrich flour. We’re gonna add niacin to it, also riboflavin, also thiamine, and also iron. Interestingly, over in Italy, they didn’t do that. They took a totally different route, one that seems almost stupid, kind of like old world peasant stupid. They encouraged people to drink wine. I mean, that seems bizarre. But it actually turns out… They didn’t know this at the time. But wine back then wasn’t very well-filtered, and it had a lot of yeast in it, and yeast has a lot of niacin in it.

It wasn’t a bad idea. It was a good idea. They encouraged people to grow rabbits, because rabbits was a cheap form of meat. You know, you could raise rabbits cheaply. The Italian method didn’t… It didn’t work as quickly as the… Kind of the stick the vitamins in your flour method, but it did work. They ate their way out of a deficiency. But here’s what’s interesting, more than 100 years later, Northern Italy, they eat better food than anyone else in the world, I would argue. Maybe you could make a case for Japan, where people are also very trim. Versus the US South. That’s where Pellagra was.

That is now… It was the Pellagra belt, it is now the obesity belt. So, we see two different parts of the world, suffered from the same nutritional deficiency, one responded by saying, “There’s something wrong with food. We need to fix what’s wrong with food, ’cause we know better.” And the other part of the world said, “No. The problem is people aren’t getting enough food. Food is ultimately what humans should eat. Let’s make sure people get good food.” And more than a century later, the results are strikingly different. We have one incredibly… I would say a region that has a very healthy, pleasurable relationship with food, and one that has a very morbid, unsustainable relationship with food.

Brett McKay: And B-vitamins are in everything. I pulled up 5-hour Energy… Like, that’s the whole thing, it’s got B-vitamins.

Mark Schatzker: Yeah, and why? I mean, and they’ll say things like… My daughter bought an energy drink that had 200% of your daily requirement for vitamins. And people look at that like, “Yeah, this is super healthy. It’s got double the vitamins.” Like, why would anybody need that? It plays into our naivete, I think, in a very un-wholesome way. But then when you look at it in terms of the role that these things play in energy metabolism, I think that’s a really bad idea.

Brett McKay: Right. So, it could be causing us… So, ’cause we’re eating… So, there’s a whole bunch of things going on here. So, this processed food that we’re eating, there’s some nutrition… Nutritive uncertainty going on, because food tastes sweeter or fatter than it really is. So, we’re like, “We gotta eat more to get the calories you need.” Your brain’s like, “We gotta… Something’s wrong here.” But, in addition to that, we’re eating more B-vitamins that metabolize calories more and kind of increase weight gain, basically. So…

Mark Schatzker: Yes. They make weight gain metabolically possible.

Brett McKay: Okay.

Mark Schatzker: Yeah. That simple. Yes, so… And you’re right, they’re two things. They’re both kind of under this umbrella of us thinking there’s something wrong with food and we need to fix it, I would say that is the big difference. If you go right back to Pellagra, Italy always had faith in food, we always thought there was something wrong with food, and we’ve been mucking around with food ever since.

Brett McKay: And so, what do you do about it? So, I mean, most of the food we eat here in the United States, it’s been tinkered with somehow. I mean, is there any way to counter this?

Mark Schatzker: Well, I mean, it can look kind of dismal when you see how much of this is going on, when you start to look at nutritional info panels and ingredient panels and see just what’s going on. It’s like, “Wow, we’ve got a long way to go.” Knowing things is the first part of it. But it is still possible to buy a wholesome food. If you buy real food… You know, a fruit, vegetables, a cut of raw meat, those are relatively untainted. Not always, but relatively speaking. So, you can still buy real food. It’s the processed foods that I think are essentially engineered to promote maximum weight gain. In some cases, unintentionally, we use things like artificial sweeteners and fat replacers thinking it’s making things better. I think they’re making things worse.

Brett McKay: Okay. If all Americans are eating this fortified food, right? Pretty much all cereals, breads, etcetera, are vitamin-fortified. Like, why is it that some people don’t gain weight? Have you figured that out? Or are they just… Are they just eating… Are they eating fewer calories or… What’s going on there?

Mark Schatzker: No. Well, I would say any time you have a population, and you add something to it, you’re gonna see a variation in terms of how the population responds. So, if you take a population and add cigarettes, not everybody gets lung cancer, not even everybody takes up smoking, but you’ll see there is an overall effect. The same thing with alcohol. When we gained the ability to distill alcohol, we could make gin instead of just drinking beer. That doesn’t mean everybody became an alcoholic. So, there’s gonna be variation in terms of how a population responds. But I do think it’s a really good question, and this is something I wrestle with. Does the addition of these energy metabolizing vitamins… Does it raise our set point? Does that actually make us fatter than we would be without it, or does it just somehow make it easier to get fat? I kind of lean towards the latter. It’s possible to become obese in Italy. The rate is far, far lower. You just have to work harder at it. I think… If I think, “What’s going on in Italy?” If you look at something like their levels of thiamine, they’re lower than what we recommend. They’re even lower than our levels of thiamine were in the 1940s before we started fortifying.

And so, what I wonder is if the… I think the idea is that the low level of vitamins is kind of like a leash on weight gain. There just isn’t that metabolic possibility of turning carbs and fat, that you eat, into extra body weight, because there’s just not the right amount of vitamins. Does that… Does that make sense?

Brett McKay: Yeah, that makes sense. And where do you see this research going?

Mark Schatzker: So, if there’s one thing I hope this book does, it’s changes the conversation about food. We’ve been on this treadmill of fighting about nutrients, fat, carbs, keto. Some of these things have helped people, I don’t deny that, but I don’t think they point to the cause of our dysfunction. So, I’m hoping that we can see that the problem isn’t… It’s with the brain. We have to understand how our brains evolved to eat, how the brain understands food on an intuitive level, and the big price that we pay when we mess with that. So, I’m already working with a scientist at the Icahn School of Medicine at Mount Sinai to test this vitamin model in rodents. That’s the first place you start. And I think we’ll see if the proof of concept is in rodents, then you start to look at humans. And I hope it also…

What I’d like to do is change… We all have to stop trying to be these nutritionists, thinking that we know about how much protein we need and counting calories and carbs and fat. The scientists who are absolute specialists in this can’t predict how much protein they’re consuming, how many calories they need. Even the subjects they’re studying, they are always invariably surprised. This idea that we have this deep knowledge of the nutritional make-up of food and our own needs is a total myth. I think we should eat as nature designed us to eat, which is to focus on the experience of food. And that’s what they do in Italy.

I had this kind of insight going on, I was visiting a Bean Festival. And yet another argument ensued about food, and this had to do… Someone was saying, “Don’t put any onions in when you boil the beans.” And a woman said, “No, no. You should put it an onion, you should also put in Rosemary.” And then, someone else said they disagreed. And then they start to argue about the type of bean, ’cause there’s more than one type of bean that’s grown in this area. And everywhere I went for this book, everybody argued about food. But there was a fundamental difference, which is that in Italy, they argue about, “Is this the best recipe? My grandmother’s recipe is yours. My villages recipe is better.” Every meal seems to be this opportunity to engineer maximum deliciousness. Here the argument is always about nutrition, “That’s got too much carbs. There’s insulin. It’s doing this. There’s too much fat.” We argue about nutrients. They argue about experience. It seems like we’re more intelligent. I think they’re right. We evolved to eat. The brain has this ability to eat that we experience as flavor, as deliciousness, and I think that’s where eating needs to go, is in the experience of eating real food.

Brett McKay: Well, Mark, this has been a great conversation. Where can people go to learn more about the book and your work?

Mark Schatzker: I would say, you know, read the book. It’s called “The End of Craving.” My previous book called “The Dorito Effect” also gets into some of this really interesting science of how the brain understands food. And I would say, be enthusiastic about food, and we should celebrate really good food and enjoy it. It’s… It’s… I would say, it’s our greatest, most reliable form of pleasure. We eat three times a day, let’s enjoy it.

Brett McKay: Well, Mark, thanks for your time. It’s been a pleasure.

Mark Schatzker: Thank you for having me. Really enjoyed talking.

Brett McKay: My guest there is Mark Schatzker. He’s the author of the book, “The End of Craving.” It’s available on and bookstores everywhere. You can find more information about his work at his website, Also, check out our show notes at, where you can find links to resources where you can delve deeper into this topic.

Well, that wraps up another edition of The AOM Podcast. Make sure to check out the Art of Manliness website at, where you can find our podcast archives, as well as thousands of articles. We’ve pretty much covered anything you’d think of. And if you’d like to enjoy ad-free episodes of The AOM Podcast, you can do so on Stitcher Premium. Head over to Stitcher Premium dot com, sign up, use code “manliness” at check-out for a free month trial. Once you’re signed up, download the Stitcher app on Android or IOS, and you start enjoying ad-free episodes of the AOM Podcast. And if you haven’t done so already, I’d appreciate if you take one minute to give us a review on Owl Podcast or Stitcher, it helps out a lot. And if you’ve done that already, thank you. Please consider sharing this show with a friend or family member who you’d think would get something out of it. As always, thank you for the continued support. Until next time, this is Brett McKay. Reminder to all who listen to AOM Podcast, put what you’ve heard into action.

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