The Rich Roll Podcast - Kevin Hall, PhD On The Science & Politics of Weight Loss

Episode Date: December 18, 2025

Kevin Hall, Ph.D., is a physicist-turned-nutrition scientist whose rigorous research has upended some of our most sacrosanct beliefs about metabolism, dieting, and weight loss. This conversation explores why diets fail, the truth behind the "slow metabolism" myth, how ultra-processed foods hijack our biology, and why the 800-pound gorilla driving the obesity epidemic isn't willpower—it's our toxic food environment. He also opens up about his decision to leave the NIH after 20 years due to political interference with his research. Kevin is an honest actor, always trying to set matters to rights amidst a hurricane of nutritional misinformation. Enjoy! Show notes + MORE Watch on YouTubeNewsletter Sign-Up Today’s Sponsors: On: High-performance shoes & apparel crafted for comfort and style👉🏼https://www.on.com/richroll Momentous: High-caliber human performance products for sleep, focus, longevity, and more. For listeners of the show, Momentous is offering up to 35% off your first order 👉🏼https://www.livemomentous.com/richroll Seed: Use code RICHROLL20 for 20% OFF your first order👉🏼https://www.seed.com/RichRoll Roka: Unlock 20% OFF your order with code RICHROLL👉🏼https://www.ROKA.com/RICHROLL BetterHelp: Get 10% OFF the first month 👉🏼https://www.betterhelp.com/richroll Check out all of the amazing discounts from our Sponsors👉🏼https://www.richroll.com/sponsors  Find out more about Voicing Change Media at https://www.voicingchange.media and follow us @voicingchange

The holidays are here. And if you're still figuring out gifts, I get it, because finding something meaningful is genuinely hard when most stuff just ends up forgotten. Here's what helps. Think about what someone actually does, what they love, what makes them feel like themselves, and then find something that supports that

instead of just filling space. For people who run or hike, On makes gear that does exactly that. Shoes like the Cloud Ultra for trails, The Cloud Runner 2 for roads, the club hoodie for recovery days. Accessories like performance socks, caps, and bags for stocking stuffers, all designed to enable movement and explore nature without getting in the way. And here's the thing. The gift really isn't the gear.

It's the runner's high, the silence at the summit, those experiences that remind you why getting outside matters. So head on over to on.com slash richroll to explore to explore gifts, the give movement. Every New Year's people talk about losing weight, and I always say, well, whatever you're going to do, make sure that you can keep that as part of your life, because otherwise, as soon as you stop doing it, the weight is probably going to increase. Too often people around the new year, and they kind of come up with some New Year's resolution to join a gym or start an exercise program or hire a personal trainer, and they tie their success.

to what's happening on the scale. People will lose weight and they'll keep it off as long as they continue that level of effort. And so, yeah, you're right. If people are white-knuckling it and saying, you know, I'm just going to do this and it's a temporary thing and I'm going to get to my goal weight and then I can relax. It's like, yeah, that's not the way it works. Nutrition isn't rocket science. It's harder. Well, we're in the thick of it now, aren't we? Right smack in the middle of it. It's all happening. One week out from Christmas, two from the new year. And listen, I'm all for being jolly. I'm here for all the holiday ho, ho, ho. But I actually always find this time of year uniquely challenging. And I actually think a lot of people silently feel this way as well. They're the taught family gatherings, of course, fraught with tension and personality conflict. and how are we going to do all of that differently this year, which is something I talked about with Adam Skolnick on the show a couple weeks back.

But at least if you're in the Northern Hemisphere, there is this interesting conflict between the busy social calendar typical of this time of year, all the parties and the festivities. And on the other hand, what our bodies actually want to do around this time of year? Because winter is the season for hibernation. And I can tell you that what my body wants from a circadian rink. rhythm perspective, at least, is mostly to sequester myself to kind of hide away from people, go to bed early, and just relish a little more silence than normal. I wish I didn't feel this way,

but I do. Maybe you don't, but I actually think this is also something that a lot of people feel around this time of year, but actually never say anything about it. Because if you do say something, then you risk coming off like some kind of party-pooping bah humbug. So there's this dissonance between the expectations that we place on ourselves and are placed on us by other people financially and socially. And what our intuition is telling us about how to take care of ourselves, all of which creates a bunch of unnecessary anxiety, which of course only exacerbates all of this.

And one of the things that I do to help quell this dissonance is I end up eating more than I usually do, which is easier than ever this time of year, of course, leaving us wondering what we're going to do about it in the new year. Now, there are no shortage of opinions on the best way to drop those extra pounds. Lord knows, there are many ways to do this. And I'm actually not here to tell you which strategy is best. But what I am here to do is hopefully provide some added context to your understanding of well-being and hopefully spare you from having to sift through a million bad takes.

because you're about to hear from Kevin Hall, one of the world's foremost and most respected nutrition science researchers, who is here today to explain exactly why people struggle to lose weight and keep it off. We talk about the research that he performed that debunked myths about slow metabolism, how ultra-processed foods hijack our biology, why weight loss triggers powerful biological forces designed to push weight back up, We also discussed the surprising science behind appetite, metabolic adaptation, and weight regain, and why environment, not willpower, is the primary determinant of how we eat. We also talk about many other topics, including the full story behind the censorship that Kevin experienced at the hands of the HHS that prompted him to resign his position at the NIH after having worked there for 20 years, which is just an incredible and revealing saga. So if you're looking for clarity when it comes to nutrition and weight loss and what actually drives long-term health, this conversation is an essential listen.

As well as one, I encourage you to share with anyone in your life who is interested in these topics and just starving for good evidence-based information. Happy holidays, everybody. And now please enjoy me and Kevin Hall. Kevin, so nice to meet you. Thank you for doing this. My pleasure. I consider you a very important figure in the world of nutrition science. You're an honest actor, a good faith actor, always trying to basically set matters to rights amidst a hurricane of nutritional misinformation out there. And I really appreciate your voice and for you taking the time to talk to me today. That means a lot. Thanks so much.

Some of the audience might be familiar with your name because there was a little bit of a, political standoff or kerfuffle several months ago between you and HHS and RFK Jr., which resulted in you resigning after 21 years at the NIH. And that created a bit of a media circus. I do want to know about that, but we're not going to start with that. As somebody who has been studying metabolism for decades, top level, like what are the conclusions that you've drawn from the randomized controlled trials that you've performed? about the relationship between metabolism, weight gain, and weight loss. Yeah, so when people are losing weight and they are decreasing their body size,

either by an exercise intervention, a diet intervention, a pharmacotherapy or something like that, they tend to at rest, their resting metabolism when they're not moving, is decreasing. Now, it seems to decrease even more than you'd expect, at least transiently, while they're an active weight loss compared to what you'd expect for their decreasing body size. Larger people burn more calories and smaller people, so it goes to figure that as you become smaller, you burn fewer calories. But it turns out in the process of becoming smaller, during that period when you're actively losing weight, it seems like metabolism slows even more than expected. This is something called metabolic adaptation. One of the most extreme cases of this was seen in volunteers in Minnesota.

who volunteered for a starvation experiment by Ansel Keys back during World War II. The idea was they volunteered to serve their country. They were conscientious objectors, and they basically said, we're going to starve because eventually the war is going to end, and we need to learn how to feed all these people in Europe who have been subject to starvation during the war. And so these folks basically were relatively lean to begin with, and 36 people underwent like a 50% calorie restriction. And you could just see their resting metabolic rate falling.

And it went down much more than you'd expect based on how much weight that they lost. A similar sort of thing was observed by us when we examined these folks in this biggest loser television competition. We saw that while these folks were doing insane amounts of exercise and cutting their calories and their diets, their metabolic rate was slowing by a huge amount as well during this program. And it stayed slow long after. Yeah, and that's something that's still a little bit mysterious, to be honest with you, because unlike the Minnesota experiment folks who they did have their refeeding phase

and they did regain some of their lost weight, their metabolic rate improved. It actually went back up towards normal. And most sort of weight loss trials that have looked at people, and unfortunately many people who lose weight via lifestyle intervention end up regaining some of the lost weight, But those folks tend to recover their resting metabolic rate as well. There's something really weird about what happened in the biggest loser study. And we have some theories about what that might be. It might be that there's something about the fact that these folks actually started off very sedentary.

They became very extraordinarily physically active during the program exercising three hours every day, seven days a week vigorously. And then even when they went home during the weight loss competition, it was an end. hour a day of vigorous activity. Even six years later, they were pretty darn active compared to where they started. So is there some trade-off going on between if you become that physically active? Does something else in metabolism slow down to compensate? That's a theory at this point. We don't really have good data. And unfortunately, it's a hard experiment to repeat. Unfortunately, the television shows canceled, so I can't just go back and do that because it was a bit of a train wreck television show, to be honest.

But, yeah, something interesting was going on there that I don't think we'd fully understand. Yeah, so correct me if I'm wrong, but essentially with this biggest loser study, the conventional wisdom or the expectation was that metabolic rate was going to correlate pretty tightly with people who regained the weight. Like, there would be a correlation between metabolic rate and the people who regain the weight and the people who are able to, you know, maintain their new lower weight, correct? and the results actually defied that on some level. Yeah, so there are several things that were surprising about the results.

One was that you would think that the more you slowed your metabolism, the less you'd be able to lose, the less weight you'd be able to lose, because after all, that's kind of physics, right? If you were burning more calories and you cut the same number of calories in your diet, then you would expect to lose more weight. Like the energy has to come from somewhere. It's going to come from body fat. What we observed in the biggest loser was that the people who were,

were most successful at losing weight during this kind of crazy competition, they were the ones who experienced the most slowing of metabolism. So that was kind of weird. It was like, okay, what's going on there? Why seemed to be completely, the expected correlation was flipped. And then there is this idea that the slowing of metabolism, well, that's got to be a bad thing, that's got to predict who's going to regain the most weight after this crazy competition. And there turned out to be no significant relationship whatsoever.

with who regained the most weight. It wasn't the folks who had the greatest slowing. It wasn't the folks who had the least amount of slowing. It was more or less random. And then at six years later, the ones who were most successful at keeping the weight off continue to have the greatest slowing of metabolism. And the only way I've been able to sort of make sense of that is that our changes in metabolism and the slowing of metabolism is a response to the intervention.

It's not determinative. The way I sort of like to think about is it's kind of like the, the tension on a spring. And if you're doing an intervention to stretch the string and the spring and thereby can cause weight loss, you know, you can do that, but the greater pullback you'll feel, right? But the greater you pull, the more weight you've lost. So the distance that you've pulled the spring is in some sense related. It's like how much weight you're losing. But the more you pull, the more the resistance, the greater the tension on the spring, that's the metabolic slowing. Clearly, if the spring had less tension, you'd be able to pull it further, right?

But the point is, is it's not determinative of how long the spring is. It's how hard you're pulling on the darn thing, right? So whatever lifestyle intervention, these folks were able to do both on the television program as well as after they went home, that's going to be determinative of how much weight they've been able to keep off. And the slowing of metabolism, while not helpful, it's really an indication. kind of like the cart, not the horse, right? It's the follower, and it's the response to that intervention. On some level, it makes sense that somebody who is attempting to lose weight

and perhaps even a dramatic amount of weight that, you know, physiologically the body would respond by slowing metabolism because it will interpret that as a threat. Like, we got to hold on to this weight. Like, this guy's trying to starve us. You know, let's keep this fat here because we might need it, right, as a sort of evolutionary adaptation. Yeah, I think that that makes sense if you're lean, right? But once you kind of cross a certain threshold, right, like how long do you really have to prepare for starvation? Most people, so humans are apes that actually store quite a bit of body fat compared to other apes. Like even lean humans have quite a bit of body fat.

We talk in the book about, like, most people have enough body fat on them to, last for months. Right. You know, starvation periods that last for longer than months, most people are not dying of losing body fat. They're dying of the infections and the propensity for infections that come along with that. And it's not clear if body fat is protective of that or not.

So I sort of expected that maybe we wouldn't see this if we were studying people with obesity because they're way above, you know, the necessary requirements. No alarm bells need to go off. Exactly. But it seems like it's the same. the same alarm bells. And how that works is really interesting to me, right? I expected, like, clearly the Minnesota starvation folks who were like 67 kilograms

on average, so pretty lean by today's standards. Yeah, they're losing, and when they're losing weight, they're losing mostly lean body mass. They're not losing as much body fat because they start off with very little amounts of body fat. So, clearly that's a case where, gosh, yeah, the alarm bell should go off. You should slow down metabolism a lot, but you're starting off with, you know, a lot of toward energy. It's kind of like, it'd be like your phone going into power saving mode, even though it was at 98% energy, right? You only really think that that should kick in after you get to 10%, right? But it seems like, for whatever reason, people with obesity seem to have the same sorts of responses to that acute challenge that is causing a calorie deficit. And whatever that is, you're right. They sort of respond to that challenge by saying, yep, we're slowing things down. We're going into power-saving mode. And I don't think we fully understand all of the mechanisms by which that

happens. Some of it has to do with the sympathetic nervous system and slowing of that. But, yeah, I don't think we fully understand it. Yeah, I mean, what is your sense of where the answer lies? Like, is it in genetics? Is it in the microbiome? Is it in the, you know, hormonal system? Yeah. I mean, my sense is that it's probably mostly in the hormonal system. One of the things that we found was that the relationship between the slowing of metabolism was related to how much the hormone leptin changed. And leptin, even though it's in a person who's kind of just maintaining their weight,

it's proportional to how much body fat that they have. When you take a person, even with obesity, who starts off with a very high amount of leptin, even though they haven't lost very much body fat yet, and you put them into this energy deficit, leptin levels crash. So it seems like that metabolic slowing is not sensitive necessarily to the absolute amount of leptin that's there, but the change and the decrease that takes place. That's a hypothesis. I don't think we have a good experimental investigation of that yet.

There are folks like Rudy Liebel and Michael Rosenbaum have done some experiments where they actually kind of try to infuse leptin at different levels to try to prevent that. And they've seen that it seems to be successful at preventing the reduction in energy expenditure, especially at low levels of physical activity where a good chunk of our energy budget goes to. So those are kind of interesting experiments that suggest. that that might be the case, but again, I don't think that they're completely determinative either.

And what do your findings suggest about the malleability of our metabolic rate? Like how much agency do we have? Like, oh, okay, my metabolism is slow. Like, what can I do? I'm going to kickstart it. I'm going to hyper drive it. You know, like, do we, can we insert ourselves into this equation to, you know, drive a certain outcome here?

I mean, there's lots of promises, right? There's lots of promises that certain supplements can increase. metabolism. And the evidence behind those is, well, yeah, maybe you can detect a statistically significant change in metabolism, exposing yourself to large amounts of these kinds of supplements, but it's pretty clinically meaningless. The times that we've actually, though, the only time, we've actually come up with really good ways of speeding up people's metabolism. This was, again, in the sort of turn of the 20th century, there was a compound that was discovered in a munitions factory during World War I, where people were spontaneously losing weight. And we were like, what's going on?

It turns out that they were exposed to something called dinitrophenol, which turns out to be an uncoppler of mitochondria. So it actually prevents the mitochondria from functioning properly, not making as much ATP as they should. And as a result, metabolism, exactly. Interesting. And it turned out to be extremely effective for weight loss, but also incredibly dangerous. In fact, one of the first things that the newly formed FDA did was withdraw dinitrol phenol from the, from medications that were allowable for use. Because it was so dangerous, many people were dying.

And it's actually not very encouraging to see that there are still some bodybuilders out there that are kind of obtaining dynitrol phenol for cutting for, you know, for competition and things like that, it's still available. But, yeah, it's not safe. What about exercise and or, like, nutrition timing? Like, what is the difference between kind of grazing lightly throughout the day versus, you know, an intermittent fast? You know, it would seem to me that these things would, you know,

both of these things would have a significant impact on metabolism. Would they not? So I think we have to separate out some of the things that we talk about in terms of, like, resting metabolism. That's kind of things that you're doing when you're not eating anything and you're not moving around, which is one of the things. That's what we were primarily measuring in the biggest losers. And when we were talking about metabolic slowing, that's what Ansel Keys was talking about in the Minnesota starvation folks, the kind of sort of basal metabolic rate. Yeah, if there is an effect of exercise and those things, it tends to wash away

after. Like, there's a period, like hours, many hours after exercise where it seems like there is some residual response, but that seems to go away. You'll go back to that same basal rate. Yeah, yeah. But there is a period, like if, yeah, after you feel like you've calmed down from your exercise, if I was to measure your resting metabolic rate, it would indeed be higher. But we're not talking for days, we're talking hours after exercise. But of course, there's the energy expenditure of exercise, right?

Which is also part of the total calories that you're burning. And obviously that goes up. there's some controversy about how much compensation in other aspects of your physical activity, like if you go for a run, do you not fidget as much afterwards or something like that? What degree of compensation is there? And then there's even compensation that could be potentially theorized that may have been what we saw in the biggest loser folks, right? They had now appreciably increased their physical activity energy expenditures. That one of the reasons why we saw the reduction in resting metabolic rate.

Those two things were correlated with each other, but again, I don't think that we have good evidence of that. But that is one obvious thing that you can do to increase your overall calorie expenditure is to increase your physical activity. To what degree some people compensate for that with other parts of their energy budget, I think, is something that there's some debate about right now. And you can't decouple that from increases in appetite as a consequence of more exercise or whatever kind of like, diet you're on that might have that whiplash effect on appetite increased later. Right. And I mean, in fact, it's really interesting that there is this coupling, right? Because we do regulate our body weight and appetite and expenditure are these coupled processes that somehow influence each other. You know, there's a lot of talk about cold plunges

or actually spending a lot of time in cold water and things like that. Interestingly, the few studies that have done cold exposure in these kind of respiratory chambers where we can measure oxygen consumption, carbon dioxide production, those folks, yes, they have an increase in calorie expenditure. Some of it is from shivering. Some of it is from brown adipose tissue, this brown fat that's specifically evolved to kind of heat us up. It's more prevalent in leaner people and less prevalent in people with obesity. Certainly younger people, more young people have it than the most that you'll ever have is as a baby. But it turns out that when you do those kinds of exposures and you can increase the total

number of calories that people are burning and you let them eat whatever they want, they actually overeat the calories so that they will happily compensate for those increased calories from expenditure. The caloric expenditure in that context is pretty de minimis, though, also. Yeah, it depends how you do it, right? I mean, if you actually induce shivering, it can be pretty darn high. I mean, it's not a comfortable feeling by any stretch of the imagination. So there's like people do studies where they kind of try to ramp up the temperature slowly

and try to get you into a range where you're experiencing the non-shivering thermogenesis. And, yeah, that tends to be pretty minimal. But once you get to the shivering mode, yeah, your energy expenditure goes up quite a lot. So, yes, also turns out to be pretty comfortable to do that for a meaningful period of time. Sure, short period of time. And, yeah, you look at the rate of energy expenditure is very high, but you're only doing it for a short period of time. So it's not really a kind of a weight loss tool because over the course of the day, while there's many, many more hours of the day, you can compensate it for it by eating more. You can compensate for it by changing other parts of your energy budget.

So it's not exactly clear. But I think that one of the ways that I thought was most interesting to kind of look at this coupling between calorie output and appetite was a study that my colleagues did. when they were testing a new type 2 diabetes drug that essentially works on the kidneys and increases output of glucose. And they did this placebo control trial in people with type 2 diabetes, and they're able to kind of have folks, many hundreds of calories are being spilled in the urine of these folks. And of course, they don't know it unless they're tasting their urine is getting sweeter.

I don't think that's a common phenomenon. So there's placebo group and these folks that are randomized to this drug. that's spilling excess calories in the urine. And if you actually look to see what happens, yeah, they lose weight, but they don't lose anywhere near as much weight as you would expect just based on the calories that were spilled in their urine.

And so we did some work with the folks at this drug company to figure out, well, how much were they actually compensating for? We're not talking about days. We're talking about happening over months. Over the course of a year, they eventually almost completely compensate for the lost calories by increasing their calorie intake,

above baseline by several hundred calories per day so that they plateau at a lower weight, but it's only about four or five kilograms lower than they were to begin with. If you'd actually just, if they just kept eating the same amount, they would have lost, you know, triple that amount of weight. Yeah, so what do you make of that? So it tells me that there's some coupling between calorie expenditure or loss of calories from the body in terms of either you're peeing them out or you're expending them through physical activity or exercise or resting metabolic rate.

And the weight change that is occurring is somehow a feedback system to the brain to very gradually and subtly over many, many days and months shift upwards the number of calories that people are eating. And we tried to quantify that and relate it to what's the degree of overall calorie slowdown that people experience when they lose weight. And it turns out to be a much stronger effect than the slowdown of calories. expenditure. So, if you kind of quantify it, for every kilogram of weight that you lose, your calorie expenditure goes down by about 25 calories per day. So you lose, you know, 10 kilos,

22 pounds, you'll be burning about 250 calories per day lower than you were before you'd lost that weight. Appetite seems to go up by about 95 calories per day. So it's going to outpace that. Yeah. And so the plateaus and weight that we see when people kind of experience our that in concert with a lifestyle change, for example, you cut calories in people's diets. Part of that plateau is because of the metabolic slowing, the smaller body, burning fewer calories, but the vast majority of it is because appetite has gone up to compensate. And people don't report that, right? They actually don't report their food intake increasing.

Like if you ask them to kind of do a 24-hour recall of, what are you eating in the first month of your diet versus at 12 months after you've stopped losing weight? And those numbers are actually quite similar. But by all objective measures, their calorie intake has climbed substantially. Maybe not quite up to baseline, but it's climbed substantially. And the way I like to think about it is that these folks are reporting not their absolute number of calories. They're reporting how hard they're still working to maintain that lifestyle intervention

and that degree of effort that they're putting in. And I think that is probably pretty consistent. It's just that they're fighting a greater and greater battle. the more weight that they lose. They're basically, the weight loss per se is causing their appetite to increase. It's causing their energy expenditure to go down. And despite that constant effort that they're putting in, they finally equalized. The biology has equalized whatever the effort was that they put in.

And so now weight plate plate plate, and I think many people get the experience of, well, what the heck am I putting in all this effort for? Yeah. I mean, we're painting sort of a bleak. you know, disempowering picture here. It's almost as if, you know, the body has this homeostatic set point. And no matter what we do to try to find a workaround, it will, it has a crafty way of making sure that it returns to that homeostatic point.

But it doesn't fully return, right? I think that's the point is that people will lose weight and they'll keep it off as long as they continue that level of effort. Now, whether or not they're satisfied with that amount of weight loss, whether or not it's meaningful for them from a psychological perspective, whether or not it's enough weight loss to be clinically meaningful. I think those are all important questions. And whether or not that that actually effort feels effortful anymore in terms of have they been

able to kind of engage in habits and work those lifestyle changes into their overall lifestyle in a way that they can find sustainable. And that's been like the key trick is that every new year. People talk about losing weight. And I always say, well, you know, whatever you're going to do, make sure that you can keep that as part of your life because otherwise, as soon as you stop doing it, the weight is probably going to increase. And so, yeah, you're right. If people are white knuckling it and saying, you know, I'm just going to do this and it's a temporary thing and I'm going to get to my goal weight and then I can relax, it's like, yeah, that's not the way it works. Yeah, we all know how that goes.

Yeah, right. There's this thing that happens in the supplement space, where the second something goes mainstream, the market gets flooded and quality tanks. Creatine is sort of going through this right now. Everyone finally gets that it's not just for gym bros, it's for brain health and recovery and longevity. But now you've got all these brands pumping out gummy versions that are essentially just candy. Momentus took a different approach, which is one of the reasons why I love them and why part of the with them. They spent years, not months, years, refusing to release a chewable until they could do it without compromising. And the result of this is momentous creatine chews, which meets what they

call the momentous standard. The same standard, I might add, trusted by Olympians and Pro Teams. Each chew delivers one gram of pure, pure creatine monohydrate, single source from Germany, NSF certified for sport, of course, and without any weird artificial stuff. you can keep them anywhere, which removes all the friction that comes with powders and shakers. So head over to livemomentus.com and use code rich roll for up to 35% off your first order. We're brought to you today by Seed. I have hosted so many microbiome experts on the show over the years, and the more I learn about this very complex aspect of our physiology, more fascinating it becomes to me. but there is one thing that is simple.

A happy gut is the foundation for a happy body and a happy life. And to get there requires care, it requires intention. It requires a daily gut health-promoting ritual that, for me, begins with seeds DSO-1. Two-in-one probiotic and prebiotic formulated with 24 strains that are clinically studied and proven to survive the digestive journey. It's been shown to increase good gut bacteria by 400%, but it goes beyond just the gut.

DSO1 supports your whole body. It's formulated to reduce abdominal bloating and intermittent constipation in as little as two weeks. And I can attest to noticing personal improvements in my digestion, in my energy levels, and overall gut comfort. So go to c.com slash richroll and use the code richroll 20 for 20% off your first month,

of DS01. This is where we're sort of tiptoeing up to the point where your findings are brushing up against a few, you know, pieces of conventional wisdom, one of which is this idea of calories in, calories out, right? And for a very long period of time, this was believed to be, you know, basically sacrosanct. Then it was challenged. And now you've, you've kind of nuanced it a little bit to bring it back into, not vogue, but like maybe perhaps it's best in proper context. Yeah, so I think different people mean different things when they say calories in calories up. And it's helpful to kind of know what are we talking about when we say this. So, for example,

there are some folks who say the only thing that matters when it comes to body fat loss. So we have to focus on what is the outcome that we're interested in is the discrepancy between calorie intake and calorie expenditure. And that's an interesting question. And it's not necessarily the case that that would be so. In other words, if you could change the type of calories. So the calories we're talking about in food are the calories that you get from oxidizing one of the three macronutrients or a multiple mixture of macronutrient,

carbohydrate, fat, and protein. And it could be that calorie expenditure depends very sensitively on what mixture of nutrients you are provided with, right? And when people were first studying this in dogs back in the 19th century, what they were doing was very interesting experiments where they were doing all these respiratory measurements and dogs, they were starving them at first to see how much body fat they would lose. And then they'd give them back like sugar.

The only thing that the dog gets is sugar. And they'd calculate how much did body fat loss low. And they'd give them back fat, pure fat, pure sugar. And it turned out there was very different amounts of fat and sugar that were to require to equally slow the loss of fat and a starving dog. And this was a mystery for a long time. It's like, why is it you had to give, you know, more than double the amount of sugar to stop fat loss slowing as fat?

And it wasn't until this guy named Max Rubner decided to start to think about things in terms of, well, how many calories are in sugar and fat. And so per unit mass, it turns out that the sugar has less than half the calories of fat. And it turned out that the loss of body fat in the dog wasn't matching how many grams of sugar or fat you were giving. It turned out how many calories of sugar or fat that you were giving made the big difference. And the implication was that a calorie is a calorie when it comes to body fat loss. But the precision of those measurements was back from the 19th century. It also didn't necessarily follow that it couldn't be, that there was some precise combination of carbohydrates and fats that could cause calorie expenditure to vary.

And if that happened, then you could still not violate any laws of physics, but you could have it so that, and this is what Atkins claimed, right, he claimed that if you cut carbs enough in the diet, you would have a metabolic advantage, he called it, which was essentially saying that the body was inefficient. at running on fat and would have to burn more calories as a result. And so you could have a situation where the number of calories that you were eating could be maybe even the same or go up. He called it the high calorie way to stay thin forever based on anecdotal reports from his patients. Look, I'm not eating any carbs, but I'm eating way more calories than I used to, and I'm still losing all this weight and body fat.

Well, the only way to make that make sense is to have calorie expenditure go up. So, again, we think of calories in calories out as these immutable things that we have total control over. And they're interacting with each other, and they may depend on the macronutrient distributions and things like that. And those are all perfectly legitimate questions to test. And so those were the kinds of studies that we were doing for quite some time, was bringing people in to a metabolic ward where they lived with us 24 hours a day, seven days a week. And we would manipulate very precisely how much carbs people. were eating, how much fat that they were eating, and measuring with the most precise methods that we had, how many calories were being burned, how much fat oxidation was there, how much carbohydrate oxidation was there, how much was body fat changing, trying to see if what Rubner had suggested back in the 19th century was true in dogs, was also true in humans. And we devised the experiment based on some of the mathematical modeling that I had been developing when I first started my career at the NIH.

and the first study that we did was actually designed in a kind of an interesting way because we thought that we could show that Rubner, while maybe close to being right, it doesn't have to be perfect, right? That there could be a situation where he could see a discrepancy. And so we designed this study to test that. And in fact, we did see a discrepancy. Clinically meaningless discrepancy, by the way. It's like absolutely.

It doesn't make a bit of difference when it comes to practical considerations for losing body fat. But we saw a discrepancy such that when the same people with obesity had a 30% restriction in calories coming only from fat versus, in another time, the same folks only from carbs, when they reduced the amount of calories coming in from body fat, they lost a tiny bit more body fat than they did when the same people had the same number of calories restricted from carbs. suggesting that a calorie wasn't exactly a calorie, but the difference was so minuscule that clinically it's totally meaningless. But, you know, as a background in theoretical physics, you know, I think that even these kind of principle times. Yeah, if that is like a hard and fast principle, any deviation at all is worthy of investigation. Exactly.

And so that's why I was excited by that result, right? And kind of shocked when I saw like these competing diet tribes take that same study and say, oh, it's either completely flawed and worthless and it wasn't low carb enough or whatever. And then another group who were pro-low-fat deaths is like, finally, you've proved what we've, you know, suggested all off. Well, this is, yeah, I mean, this is rampant, you know, in every tribe of every diet cult. But the point is is that the physiology is incredibly complicated. And even how the body achieves this near equivalence, and even though it's not precisely equivalent, is incredible, right? Inside the body, it's like the hormonal system stands on its head in order to manipulate

what the different fuels are shuttling between the different organs, how hormones are changing, just to make it so that it's approximately true that when it comes to body fat changing, something that Rubner had no idea about it. It was a black box for his dog experiments. He didn't know about insulin. He didn't know what the liver was doing, what the muscles were doing, what the pancreas was doing. No clue about the inner workings of the physiology. But it's just so fascinating that the implications of this is that we can survive as humans or dogs on a wide variety of macronutrient distributions.

And when it comes to storing or mobilizing calories from our body fat, the professional organ that is there to store calories, it's more or less equivalent. And it doesn't have to be perfect. The human animal is highly adaptive and resourceful. You know, what I take from what you just shared is essentially everything is more complicated than you think it is. Yes, calorie in, calorie out, sure, but more nuanced than that, you know, the carbohydrate insulin model or, you know, the hormonal kind of view of this whole thing. True, but also more complicated than perhaps we imagine. And then I think on top of that, there's the added layer of complexity, which is that the scientific method, you know, by its very nature is a reductionist. and to apply a nutritionally reductionist approach to all of this is flawed in and of itself

because just macronutrient ratios aren't telling the whole story. You have to contextualize it in the holistic food, like the food matrix itself. Like how much fiber is in this and what does fiber do to the uptake of calories, et cetera? And this is, you know, like it just gets super murky from there. And then perhaps, you know, I'm interested in like, can you draw conclusions from all of this, given, like, the vast complexity of all of it? I mean, it's incredibly hard, right? And I think that that's, as scientists, we have to be really humble in kind of saying

what we think we know about a system and what things do we have a certain amount of confidence in and what things are just really beginning to be understood. And I want to take you back to it's not just the nutritional complexity of food, but it's the food environment that we find ourselves in, right? So kind of going back to the comment about these different feedback loops that we talked about that are preventing us from losing more weight than we would like and the effort that's involved in keeping weight off in a given environment. Well, the funny thing is that, and we're only beginning to understand this, you take that same person and you shift them to a different food environment. What was effortful before is no longer effortful. In other words, whatever points that we're regulating our body weight and our appetite

and our energy expenditure, those controls that are helping us regulate body weight, turns out to be incredibly influenced by the food environment that we find ourselves in. So, you know, I was doing these studies where we were manipulating macronutrients and observing these little tiny, clinically meaningless differences. But as soon as we started to do experiments where we basically said, look, eat however much you'd like, we're just going to change the foods that you're exposed to. Now we're starting to see hundreds of calories a day differences. And when these people are being told, eat as much as you'd like, don't be trying to change

your weight. We're measuring lots of stuff. What you don't know is we're measuring all your leftovers. And we're going to calculate how many calories you decided to eat on these different food environments. And they're really short-term studies, lots of limitations, very artificial food environments. But the point is that the environment is somehow. interacting with our fundamental biology in ways that we still don't fully understand and is making

it so that whatever point we're regulating or whatever narrow range of body weights that we're regulating is so influenced by the food environment. And the neuroscience of that is only beginning to get unpacked. It's a really fascinating sort of observation that despite people not trying to change the numbers of calories that they're eating and trying to change their body weight, they're spontaneously changing them by hundreds of calories per day, spontaneously gaining weight, gaining body fat, losing weight, losing body fat without any effort whatsoever. And I think that's incredibly fascinating. And it's also suggests that maybe that's what we're seeing in society writ large when it comes

to the increasing amounts of average body weight and the increasing prevalence of obesity that we're seeing, is that something about our food environment has changed. and the science of that is, I think, still beginning to get unraveled. It's the environment, stupid. You know what I mean? It's like we can argue about the food pyramid or the food plate and like all this sort of stuff. But fundamentally, it is, you know, you're going to eat what is in your environment. And if there is a core kind of theme or thesis to all of your work, it's that, you know, this obesity epidemic, this, you know, incredibly precipitous rise and chronic lifestyle ailments are,

primarily the result of toxic food systems. It's a systemic issue. And all of this focus on willpower or the failure of willpower and individual food choices has to be contextualized within that in order to really understand what's going on and craft solutions that are going to be effective. Right. Yeah. I think that that's right. And the degree to which some individuals might have a lot of success, even within a given food environment, some of it is by, limiting the foods that they're exposed to, or limiting the foods that are on their list of things that they are even deeming possibly acceptable. So I sort of view that as a pseudo sort of local environment shift in that way.

And the folks who have, you know, the privilege and the interest and the energy and the motivation to kind of engage in that sort of local environment shift and have access to the kinds of foods that are likely to drive the body, regulatory system in the positive direction, yeah, clearly they're going to have the most success. And there's lots of roles and lots of good reasons to kind of engage in those with those folks on an individual by individual level. And there's lots of people whose careers are made on that sort of thing. And I completely encourage that. But I think it overlooks the fact that, you know, body size in a given environment is, you know, 40 to 70 percent heritable. And that some of us are more genetically susceptible to shifts in our food environment than others. And at the population level, what we have to account for is the full complexity of that

food environment. So it's not just the foods themselves. It's the context and how they're advertised. What are the most inexpensive, the most convenient, the most readily available foods? You know, what are our skill sets? How are we relating to our, in our social situations? Do we have supportive folks who are going to support us to make changes in our local environment or are they going to resist those changes? It gets incredibly complicated. But

at the broadest possible level, it just seems like the most obvious explanation for what we've seen happening. The shifts in the body size distribution, I mean, they started happening, you know, centuries ago, in positive ways, right? We saw increasing weight and increasing height where as a result of nutritional deficiencies, right? Something shifted as we kind of got into the middle of the 20th century. And that's, you know, where we get into the major shifts in the industrialized food system and whatnot. So I love the fact that you're, you're very kind of anti-diet tribalism. Like, you know, listen, you can be healthy and sustain weight loss on a low-carb diet, on a high-carb diet. Like, we can quibble around the edges there and people

can fight and go to loggerheads over all that kind of stuff. But fundamentally, the 800-pound gorilla in the room is ultra-processed food. So when we're talking about food environments, I mean, that is the kind of lurking giant that's driving all of these deleterious health outcomes. Yeah. I mean, the way I sort of see it is even taking one step back, which is, you know, ultra-processed foods are the consequence of what we call in the book the calorie glut. So ever since the introduction of agriculture, humans have struggled to provide enough calories to feed populations. That was been the kind of devil's bargain that was struck when we moved into agricultural systems as society populations could grow. Less and less people were responsible for

producing food, and we got civilizations and whatnot. But at the same time, we were always threatened with population growth exceeding the ability of agriculture to feed populations. And there's obviously periods of mass starvation. Thomas Malthus, kind of a very famous 18 century thinker basically made this observation that we're basically doomed to starvation because agricultural productivity and yield cannot possibly keep pace with what he saw as exponential growing populations. We bucked that trend for the most part. Yeah, I think we have pretty much.

But it's interesting. I mean, it's crafty, you know. It's amazing. It's kind of ingenious. The solutions that humans came up was to solve this. It is amazing. And we think that, okay, yeah, that's 18th century Thomas Malthus. It was, you know, biologist Paul Erlich, even in the 1980s, was still saying that we would have mass starvation in America.

Right around the same time, we were seeing an explosion of obesity prevalence. And, you know, it's amazing what we've been able to do with agricultural yields and industrialization of farming and whatnot. But we basically put in place in the middle part of the 20th century all of the resources and research to maximize calorie production, especially in places like the U.S. and Canada and Europe. We did a calculation for the book, which I thought was kind of interesting. If you just take the four commodity crops for food, rice, corn, wheat, and soy, and you ask the question, how many calories per person per day, are produced in those few commodity crops. It turns out to be 15,000 calories per person per day. So six-fold, you know, what the nutritional needs are.

And we've been finding ways to kind of get rid of that glut of calories, right? A huge chunk of the soy and the corn goes to biofuel production, right? Which for many people. And animal agriculture. And then animal agriculture is the other big chunk of it, right? And the reason why that sort of works to get rid of it is because, well, animals have a metabolism, right? They don't just kind of translate one calorie of corn into one calorie of meat, right? They waste a lot of those calories by living, essentially. And so it's a very

inefficient process, animal agriculture. And so yeah, so at the end of the day, you end up with something more like 4,000 calories per person per day in the actual food supply of America. And even that increase since the 1970s is more than enough to explain obesity. It turns out that about two-thirds of the increase in calories in the food supply, after accounting for animal agriculture and the exports and the biofuel production, two-thirds of that increase went in the trash. Yeah, you have this interesting correlation between the increase in food waste and the increase in obesity.

Yeah, and I don't think it's an accident. I mean, I think that the point is that we have produced this calorie glut and come up with very clever ways of offloading it, both in terms of animal agriculture and biofuel production. And the other part is ultra-processed foods, right? It's taking those cheap, high-yield inputs to the food system and coming up with incredible ways to transform them. Who would have thought you could take corn and make basically sugar, high-fructose corn syrup for use in products? Substitizing it to artificially deflate the price of it to make it widely affordable. hyper palatable, highly caloric, nutritionally deficient, and also something about it that makes

us want to eat it quickly, you know? So that we're ahead of our sort of appetite suppressant, you know, impulse. Right. And I think that there's, you know, a lot of people say that, you know, the food industry knows all the mechanisms by which these things cause us to overeat. I don't, I don't necessarily think that's true. I mean, I'm sure that they're trying to come up with incredibly tasty products that do well in the marketplace, right? And when they fail, and many of them do fail, they basically re-engineer a replacement and put it back. It's like evolution, right? It's like selection of the fittest products in the marketplace that are maximizing sales, right? And what happens if you put Fritos in a Taco Bell burrito? You know, and people like that?

Exactly. It's like, let's try it out. We got a little focus group they said they liked it enough to let's try it out. And yeah, that's the food environment that we're experiencing right now. now. And I think the point is both in the agricultural sector, all along the path, we have these externalities that are not part of the equation, right? All of the environmental damage that was done to kind of do this industrial agriculture, all of the problems with the animal agriculture just from a moral perspective, as well as, you know, the manure that's produced and the methane that's produced and climate change. And the depletion of the soil.

So the nutrients that end up in the food are less than they once were. Yeah. I mean, there's some debate. There's some debate about that, I think, about how important that is. But I think that there are certainly cases where that's been shown. The other big externality has been health care costs, right? I mean, the fact that we are experiencing this dramatic increase in diet-related chronic disease that is essentially bankrupting Medicare.

Medicaid and the health sector. And to think that this entire process of solving Malthus's, which is essentially we've solved Malthus' problem, right? And we have to do something to kind of change this, not just for the health crisis, but the fact that we're going to have 10 billion people on the planet in not too far distant future. That solves Malthus's problem because the population is no longer expected to increase. What do we have to do to the food system to both ensure that we have equitable distribution of calories and those calories are actually healthy for us and the planet?

That's the grand challenge of agriculture and nutrition and food science for the next, you know, several decades. And we need to think about it in this context. In some sense, like the obesity and diet-related chronic diseases are like the epiphenomenon, right? They're the thing that happened because we front-loaded all those calories in the agricultural system. Now, we've got to figure out a way to steer past that. Fortunately, we have some therapies that are entering the market that can help the folks

who are most genetically susceptible to those changes in the food environment. But we've got to think past that as well and look to see, you know, where do we want to end up when we have to feed 10 billion people a healthy diet that's equitably distributed as well as sustainable for the planet. Today's episode is brought to you by Broca. You know, it's funny, we don't often think of eyewear as performance gear until it starts to get in the way. And if you're like me, somebody who has contended with eyesight impairment my entire life,

it's a very real thing without a real solution for athletes. I cannot tell you how many times I've been mid-run, constantly shoving my glasses back up my nose, tripping on roots and rocks, because I couldn't see them. or my glasses had fogged up, or what about out on the bike, where the treachery is obviously far more intense? Well, this is why Roca has been a godsend for me, approaching prescription eyewear from a performance perspective first, but not at the cost of fashion, I should say, helping not only people like me, but all kinds of athletes, including Tour de France cyclists and Iron Man champions with everyday frames disimperable.

Their secret is their proprietary gecko technology. patented nose and temple pads that grip even more securely when you sweat. No slipping, no distractions, and they're insanely lightweight. Most frames weigh less than a pencil, super light, even with prescription lenses. Beyond the function, the craftsmanship is next level. Razor sharp optics, durable construction, and a design that actually is beautiful and keeps up with you. So put them on, feel the difference, and wear without limits. Unlock 20% off your order with the coat rich roll at Roka.

dot com that's r o k a dot com this show is sponsored by better help the holidays bring up a lot on the good side we've got all these family traditions anticipation recipes passed down for generations and for a lot of people that's really beautiful but for many others this time of year is a little bit complicated like not so great family patterns of behavior that flare up the awkwardness

that uncle says the weird thing that he knew he was going to eventually. Social cues get misinterpreted. You know what I mean. Not all traditions serve us. Some are just things we inherited that don't really fit who we are anymore. And I'd like you to consider that perhaps this might be the year to rewrite all of that, to create new traditions that actually mean something to you, whether that's starting fresh or letting go of these things that historically don't work and never have. Therapy during December is a pretty great way to do just that, to process all of the complexity of this time of year, to close the year with clarity, and to navigate it successfully instead of just trying to survive the chaos. And this is where BetterHelp can really be of service to you. BetterHelp is served over 5 million people worldwide with more than 30,000 licensed therapists with an average rating of 4.9 out of 5 based on over 1.7 million client reviews.

So this December, start a new tradition, taking care of you. And right now, all of you guys, our listeners, get 10% off at betterhelp.com slash richroll. That's betterhelp.com slash rich roll. I mean, here's where everything bifurcates, because on the one hand, we have personal choice. You know, what are we deciding to put in our mouths, you know, a couple times a day, what's available to us and affordable. What is the extent of our personal agency and our relationship with our own bodies?

And then there's public policy and what's good for the whole and what are the systemic changes that we need to make for a healthy planet and a healthy populace, all of that. And those are two sort of different discussions. I mean, they inform each other,

but I think in the conversation around, you know, well-being and addressing the obesity epidemic, these two things get conflated and confused with each other. And perhaps this is where you kind of butt up against HHS here a little bit because there's such a palatable irony here because you're raising the alarm of ultra-processed foods. Like this is really what's driving all of the problems,

which is in parallel with everything that RFK Jr. is saying and what the whole Maha movement is about, right? So you would think, hey, you know, you're an ally to this. movement. But your research didn't exactly line up with whatever RFK decided was the truth, and this is where this conflict arose. Can you talk a little bit about that? Yeah, sure. I mean, let's go back even before the last election, right? So before the last presidential election, this was a bipartisan issue, right? And we can go way back when it wasn't a bipartisan issue with Michelle Obama in the Let's Move campaign. It was clearly a democratic issue,

and people were interested in proving our food and addressing obesity, that was clearly a... Yeah, and that didn't go so well, right? For all that's good intentions and whatnot, it did not go well. But there was something different that was going, and I think a lot of it had to do with the discussion about ultra-processed. Because we've had these discussions back, you know, it's either been sugar or saturated fat or sodium and salt that have all been like public health enemies. And they've all had, there's a lot of data behind those kinds of campaigns and why it would be better for people to eat less salt and eat less saturated fat and eat less sugar and things like that. And I don't think there's many folks who disagree with it, but they didn't really capture enough public attention, especially at the political level, that, you know, I don't remember seeing a Senate hearing about, you know, added sugar, right? Well, it was, it was interpreted at that time, and perhaps that was a failure of the messaging as an affront to personal liberty.

Like, the government's going to tell you what you should eat. And, like, how dare they, you know, kind of intrude upon my personal choice? Right. As opposed to, hey, there are shadowy, you know, giant corporations who don't have your best interest at heart here and they're out to get you. Or, you know, there could have been a different way of communicating that message at that time. And I think possibly that's part of what this idea. of ultra-processed food has kind of brought to the table has been the fact that all of these things are important about the nutrient properties of the foods that there

are and the way that they're marketed and the overall system of food that we're experiencing and how it's changed since you know the middle of the 20th century and so yeah we had like you know Bernie Sanders Cory Booker you couldn't tell their comments about this from Bill Cassidy or RFK Jr. at the time it was like it was and I still think that if you talk to Cory Booker today, he would probably tell him, well, he's on honeymoon, I guess, right now. Yeah, he's on honeymoon right now. No, but this is an issue that he cares deeply about.

Exactly. And has been working on for a very long time. Exactly. And so I still think that for this particular set of topics, there is bipartisan support. And before, you know, this current administration, nutrition science has been funded horribly by the NIH for a very long period. So it's not a new situation that the funding has been anemic. Exactly. And we've been focused, I think, you know, this is a good justification for doing this. But there's been a huge focus on the sort of biomedical program of let's figure out how to treat and cure disease, right? No one's going to argue with that, right? Everyone wants to be able to cure cancer and treat diabetes with better, you know, therapies and whatnot. But there has been less emphasis and less funding on nutrition science and prevention and the environmental drivers of disease prevalence.

Because... It's a great question. Is it, you know, is it big food lobby money that is influencing appropriations? I don't know. I honestly don't know. Lack of political will. I mean, I would say that there's probably, let's face it, when do people get exercised about, you know, disease? It's when they get a disease or a loved one gets a disease, right?

And the first thing they want is a cure. So there's a huge amounts of lobbying from organizations. and people who have already suffered the consequences of diseases that were put in motion by environmental drivers a long time ago. And the ask is not, let's fix those other things that have driven this for my grandchildren. The ask is, I want to know what it is that I'm going to have to do to get a cure in the few years left that my parent or my child has this disease. that's a very powerful message that resonates with people. And I don't want to take anything away from that. Sure, the acute nature of it.

But far more people are walking around thinking, how come I'm getting fat and how come I can't lose weight? Like, I mean, that is just, you know, that's like you're capturing like 80% of the population or probably more. And to be fair, we've come up with pretty decent treatments in recent years for several of those things. And I think that that's a good thing for those things. But it doesn't mean... They're not root cause solutions. They are not root cause solutions. That's correct.

They are solutions for some people. And I don't think we should minimize that. And like I said, they are part of the bridge that's going to get us to what we need, where we need to go with our food system. By this, you mean like bariatric surgery or GLP ones. Yeah, exactly. Like, these are treatments for the ones, the folks who were most genetically susceptible to the environmental changes that have put in place the increase in obesity prevalence and

the downstream consequences of that. We thankfully now have effective treatments, and some of them can scale at a level that will help many of those people. I think that's a great thing. But I think you're right to point out that funding to figure out, how are we going to move past this and what was the cause of these problems in the first place? It's been underfunded, and nutrition science in particular has been underfunded. I think it's tragic.

And, you know, I experienced that even in the last administration. What we've, after we had this big paper on ultra-processed foods come out, showing that when people are exposed to environments with lots of ultra-processed foods, they ate many, many more calories. They spontaneously gained weight and gained body fat. Shocking. Without that result. And then shifting them to a minimally processed environment.

Again, these environments were matched for the number of calories that were presented to people, the macronutrients, the glycemic load, and the fiber. and the sodium, and yet. And the nutritional dark matter, which we haven't even talked about. Which we haven't talked about it. So they've experienced this change in that food environment spontaneously. I just decided to eat less. I'm not trying to do anything.

Just effortless shifts. After that study came out and it garnered like way more attention than I thought it was going to get. They wanted to close down the unit at the NIH. And this was prior to 2020. This is before the Trump administration. This is 2019. Yeah, yeah, yeah. So the same year that that paper came out, we were told by the CEO of the clinical center

that they were going to close down the metabolic unit. I remember sitting in a room and afterwards, I said, you know, I just, I don't see how I can have any confidence that I can continue to do our studies if this unit's closed. And he said, yeah, you shouldn't have any confidence that you can continue your studies. And what is your theory of mind there? I mean, what is the motivating? The motivating fact was that, you know, I think he had plans for that facility that he thought were better suited. And we can have a debate about that. And he was in a higher position at the age than I was.

And, yeah, I think that there are several theories. I think he wanted to maybe set up an Alzheimer's unit. I'm not exactly sure what the different competing theories were. But we could have a debate about that, but that was the debate was sort of shut down. And I ended up finding out someone at a higher level at HHS who had read our paper. And I said, hey, I heard you read our paper and we're intrigued by it. It's too bad. We won't be able to figure out what the mechanisms were because the unit's going to get close.

It's outrageous to me because like our entire, you know, epidemic of chronic lifestyle illness all tracked back to this, right? And not only is this driving all of these, you know, incredibly poor health outcomes and debilitating millions of people on. necessarily, it's at the root of what's, you know, ailing our health care system. Like, it's going to, and it's so from an economic perspective, uh, which then becomes a national security issue, like these are gigantic problems that need to get solved that are, you know, important for the kind of the sanctity of our, you know, our democratic union fundamentally. Like, it's more than just people are getting sick. Right. Right. Right. This is why health care is so expensive and so bureaucratic and so, you know, kind of overwrought, right?

now, and we have to solve it if we want to figure out health care. I completely agree. And so while we were successful at pushing back against that attempt at closing our unit, so that's why, you know, in the run-up to this last election, with the attention that this was receiving on both sides of the aisle, I was super excited, right? I thought, not only... Because here comes a guy, and he's talking about this stuff that I'm studying and that I care about.

But prior to that, before we even get there on the timeline, though, is it true that You almost got fired for writing this book? Like, this is before the current administration, right? That is true also. What? What? Yeah. Like, you're just a guy at NIH doing research on processed foods and metabolism.

Yeah, that's true. What's the big threat? Well, I think there's a couple things, right? And it was expressed to me that two main concerns. One was that we have an entire chapter about policy. The NIH has always sort of brought it itself as we provide the science. We don't opine about policy decisions. Right. We don't want to get involved in policy decisions. And the second thing that

they pointed out was that the other thing we point out is in the book, there's a lot of, I wouldn't say it's debunking, but it's a lot of challenging of claims that various folks are making in different spaces, like the different diet communities, the different folks who are selling supplements, who are selling precision nutrition, programs, and they didn't want pushback from... I see. And because you're a government employee, it's creating a headache for that. Yeah, so I initially said, look, what if I just kind of, you know, not put my affiliation

on there? And there was, they didn't agree to that. And they said, no, if you're an author of the book, you're going to be disciplined and likely removed from your position. And so I actually had to hire a lawyer who is well known for, he's well known for basically representing clients who write books after they leave the national security space. And he's like, are you trying to like reveal some, like classified infertial? I'm like, no. And he's like, I don't understand it.

This is the most bizarre thing you'd ever see. Anyway, he was able to kind of basically get the NIH to assent to letting me be a co-author of this book. And by the way, keep your job. Keep my job, right, which I've since left, which is the other part of the story, right? So, yeah, so I guess the point was is that, you know, after that was resolved, and I thought I would be continuing with the NIH, and this new administration was coming in and that there was bipartisan support for finally kind of investing in understanding what's going on and tackling these issues of diet-related chronic disease and ultra-processed foods. You know, I was very excited about this. In fact, I started working with the director of the NIH Office for Nutrition Research about, you know, we've been doing our studies, which are pretty small scale. They take years to complete because we can only house two or three people at a time.

What if we had facilities for other researchers where we could house people for more comfortably, not in a hospital, and keep dozens of people at a time, get answers to these questions that the American people deserve in a matter of months rather than years? And we could cycle through different hypotheses and different mechanisms that we were studying. And we started to work on a plan of how we would do this. And I was trying to contact members of the Maha kind of leadership to talk about this, but they were too busy talking to social media influencers at the time. But, you know, we were plugging along doing our work. Eventually, I wanted to be able to kind of present this sort of plan to folks. And, you know, in that transition period after the new administration took over,

we started to see that certain topics were deemed sufficiently politically interesting that any sort of work that would be communicating results, going to conferences, any new programs had to kind of go up to the level of the Department of Health and Human Services and be approved by a political appointee. And so I started to experience this directly. The first occasion was I was supposed to give a talk at the Bloomberg Philanthropies annual meeting about some of our work on ultra-processed foods. And, you know, for the first time, at that time, 21 years at the NIH, I was denied the opportunity to give a talk at the conference. Now, it was unclear exactly at the time was this because of travel restrictions?

And so I went back to the Bloomberg folks and said, could I do this remotely? Would you mind if they're like, yeah, no problem. So re-requested the ability to do this, still denied. And this was at a time when my colleagues were being allowed to give talks, especially remote talks. So there was something special about the results that we were trying to present that was being, you know, suppressed in this way. We were interested in the question, does ingestion of ultra-process foods hijack the brain's rewards system in the same way that cocaine does? I guess the question is addiction doesn't necessarily have to occur through this particular biological pathway. Yes, this has been a common phenomenon in that drugs like cocaine and methamphetamine, even nicotine, cause an outsized surge and dopamine in the brain, which leads to a bunch of adaptations that can lead to addiction.

There's a very long history even in the obesity space of looking at neuroimaging studies of the brains in dopamine receptor. and people with obesity and people who are lean and saying, hey, look, the brains of people with obesity look more like people who've been addicted to cocaine than the folks who are lean. And so there is this particular neurobiological mechanism of addiction, which is well understood with cocaine, but it's always been hypothetical when it comes to food addiction. And so that's the reason you do research in this area. Right. So let's look at it and figure out if that's truly the case.

Exactly. We found in this study, it was a very large study, the largest study of its kind, and it was designed to assess the question of whether or not people with obesity have the same sort of adaptations in dopamine receptors that you see in people who are addicted to drugs over the long term, implying that people with obesity might be more likely to have food addiction. And secondly, whether or not they see this outsized dopamine response, similar to cocaine ingestion? And is that different between lean and obese people? And we did not see that

latter effect. And so we wrote this paper and the paper was written and submitted before the administration came in. It was accepted for publication. We were starting to want to talk about it at conferences. And so you're right that it was perceived, I believe, by folks at the political level at HHS as saying, I don't need to think about it. I know that that they called a reporter from the New York Times, the communications director, and said, the results of this paper don't match RFK Jr.'s thoughts about ultra-processed foods. It was politically inconvenient, and so they interfered with your ability to have a press release and to speak to the New York Times about this.

Correct. And they edited my answers to the reporter's questions. They provide written responses where they editorialized what you had to say without giving you the opportunity to... Well, no, actually saying that I... wrote it. Oh, really? Yes. It was attributed to be. It was provided to them in your words. Were you able to get a correction from the New York Times out of that? No, I was in communication with the reporter for the New York Times. So I just made sure that she quoted only from the sections that I had written, not the, not the embellished sections that downplayed the study. So, yeah, this was like direct interference with the ability to communicate these results. And so at the time,

they're trying to get as many people to leave the NIH as possible, and they put up this early retirement option several weeks later. And so after experience. This was like in the middle of Doge. Yeah, yeah, exactly. And we had ongoing studies. And, you know, again, I wanted to kind of talk about the plans for what we, how could we improve this situation? I'm completely aligned with the, you know, the goal to make America healthy again, that ultra-processed foods, we need to better understand how they might work and what the mechanisms are. And so I wrote to RFK Jr., his senior staff, I wrote to the NIH director and said, look, here's what I've experienced.

At that time, we actually also weren't able to buy food for our research participants. We couldn't buy research supplies. We weren't able to rehire people who were leaving on a regular basis that run our studies. It was like a very bleak time. Fortunately, some of those things have turned around a little bit at the NIH. They're still experiencing some of these difficulties, purchasing research supplies, for example, still to this day. But we were experiencing really acute problems. And so I was, and I've been talking with our scientific leadership, like, what's going to happen here?

Right around that time, it had leaked that there's going to be a 40% cut to the NIH budget and very dire time. So I wrote to these folks and said, look, not only were we experiencing these problems, but you know, we're totally aligned and we can make a lot of progress. In fact, I told them about this ongoing studies, how we're making progress, understanding mechanisms of ultra-process foods. Why do they make people overeat? That we'd been able to redesign an ultra-process diet that was still 80% of calories from ultra-processed foods that didn't actually cause people to overeat by focusing on mechanisms,

that we could do a lot more in the future. if we kind of engaged in this plan and I sent them the copy of the plan, you know, actually requested a meeting. And I basically said, otherwise, I can't see how we can continue research in this space. And, you know, I'm going to prepare to retire through this program. And so I didn't hear anything as a result of that, except a colleague of mine said, hey, are you really going to retire? And I'm like, possibly, how do you know? And he said, well, this. Your email was circulated among senior staff at NIH, and so someone read it, but nobody reached back out to me. So I spent the next week's kind of reassigning staff and reassigning my clinical protocols and closing down a 20-year career at the NIH because I didn't see a way to kind of move forward if we're going to be interfered with in this process and that there was no interest in engaging in this topic at the same time that they're holding, you know,

meetings with folks drinking raw milk in the White House. I mean, it's just unfortunate because, you know, there is a lot of energy around ultra-processed foods and what's happening there. And, you know, he's, you know, very much a flashpoint and drawing attention to this. And, you know, and that's a good thing writ large. And you could have been this ally. Like, you're the guy who's looking at this more closely than anybody else. Like, it's just, like, it's confusing why there couldn't, you know, be some kind of

consensus about how to move forward together on this. Yeah, and even more disappointing, and I think one of the things that solidified why I think I made the right decision, because obviously I agree with you, and I think that, you know, we could have made a lot of progress. You know, after I left, and it made a little bit of, you know, press coverage. Yeah, there was actually a lot. Yeah, there was quite. You were, you were, that must have been strange for you.

It was a little strange. You know, a scientist at NIH, suddenly, you know, Jake Tapper's talking about you. They're just kind of everywhere. Well, the interesting thing about the, so the day that I talked with Jake Tapper, earlier that morning, I met with the NIH director, the new NIH director. Jay Batacharya. Yeah. So he saw the New York Times article that came out like I think the day or two before that,

and he said he wanted to meet with me. And so I went back to the NIH and he wanted to know what happened. And I was there with him and the deputy director for intramural research. Intramural research is the part of the NIH. that does their own studies. Extramural is the granting part of the NIH. So this was basically my boss's boss's boss and the NIH director. And he was interested in the censorship thing because he feels like he was censored during

COVID and it was clear he could probably have talked the entire meeting about that. But I tried to transition and he told me he had not seen my email and I believe them. I mean, he was new to the job. Somebody probably saw it in his staff, but I believe him when he said he hadn't. seen my email. And what I wanted to focus attention on was, what about this plan? Like, you know, the purpose of my email was, yeah, I wanted to tell you about the troubles that we were experiencing the censorship and whatnot. But the main part was, could we get on the same page and actually improve the science to investigate this, to get the answers that the American people

deserve? And you're right. There is so much passion about this issue right now. And it had been clear that he saw, you know, the email that I wrote, and he saw the plan. And he said, yeah, I'd really like to work with you on this. And he shook my hand, and he said, welcome back. And I said, well, I'm not back yet. I've got nothing to go back too, right? My lab has been closed. My staff has been reassigned.

My protocols are being run by other investigators. But I'd be really interested in working on this with you. And he said, okay, we'll talk to Nina, and we'll figure something out. And I got back in touch with the director of the Office of Human Nutrition Research, and we continue to work on this program. He presented it again at the NIH. We were talking about funding for a facility, maybe even located at the USDA Belsville facility, which was slated to be closed. They have a big metabolic kitchen and buildings that could be renovated. And I thought I was going back.

I was pretty sure. The director of the NIH basically said, welcome back. I mean, if he can't hire you back. Yeah, it's like if he can't hire you back, I mean, who's going to? Exactly. So for weeks, you know, I was working with Drew at the Office of Nutrition Research and the intramural, you know, the deputy director for intramural research and kind of putting together this plan of what we would do. And then out of the clear blue sky, Drew calls me up. one day and he said, I don't know what happened, but it's killed.

We're not doing this. He had no explanation. He said, I tried to get an explanation, but I couldn't get one. He said, the closest thing that I can think about is that, you know, this is personal it has to do with you. And I'm like, well, that doesn't make any sense because if they wanted to make it personal, they would do it and then not hire me back, right? That would be the biggest, you know, way to get back at me.

I don't understand what happened, but apparently somebody decided for whatever reason and still has not been made clear that, you know, actually investing in this research to better understand, you know, how our diets and our food environments affect that related chronic disease was not sufficient interest to actually fund that research. You know, what I've sort of interpreted this as, and since we've sort of seen other examples of this, is that science only complicated. rhetoric, right? It only introduces complexity and nuance. And when you're trying to make a case for something, especially if you're kind of come out of, you're a lawyer, you know this, you want to

come at it with, you know, the strongest possible case and rhetoric that you can, that you can come at it with. And you want to downplay evidence that might introduce that nuance and suggest it maybe isn't so reliable and upplay evidence that is really supporting your side. And doing Having really good science can only potentially complicate your narrative. And a complicated narrative is more difficult to get action on than a simple narrative. And my view has been that, unfortunately, this administration views science as a complicating factor, getting in the way of what they want to achieve as opposed to. I mean, the most charitable, that's a very charitable interpretation.

The most charitable would be, listen, we really. want to solve this problem, but we have to have these reductive talking points, and we can't have anything compromising that, because that will distract from the solution. The less charitable interpretation is that you're a political liability, because objectivity is in opposition to the political aims. And when it comes to your solutions, your systemic solutions, there are cross-purposes with the deregulation mandate of the administration outside of HHS. Yeah, and that's a huge challenge for them, right, is that there is a presidential executive order that for every new regulation, you have to remove 10 others, right? So how are you going to introduce new regulations on food if you have to remove 10 other ones at the same time?

And I think that that's part of the other thing, and I know Jessica Nurek talked at length about this, is that the rhetoric doesn't match the actions, right? Right. You guys agree on the fact that Maha is identifying the problem correctly. It's just that there's a difference of opinion when it comes to solutions here. Right. And that I'm a firm believer that science is the best thing that humans have come up with to get closer to the truth. And science-based kind of policies are the best thing that we can have to actually improve the situation. And so we need to invest in the science in order to improve. the situation. And if you don't, if you just think that you have it all figured out, and the history of nutrition and food science has been a repeated, on repeat, as we discuss in the book, people thinking they've got it figured out and they come up with a very simple sort of narrative only to be, you know, fall apart when it's subjected to critical tests.

And yes, we're making progress, but very often those simple narratives fall apart when you subject them to test. I think that the example that we were coming up with was, you know, the dopamine story doesn't seem to be holding up as well as we thought. It doesn't mean that people aren't addicted to food and ultra-processed foods might be more addictive in other ways. But it definitely complicates the narrative if you can't say, yeah, it's exactly like cocaine. Well, I appreciate your candor in sharing that story.

I'm sorry that that happened to you. I'm sure you'll find, you know, your next thing and, and, you know, perhaps even reflect back and think, well, it's good that this happened because now I'm here. Yeah, yeah. You're trying to figure that out right now. But I want to shift now to trying to provide people with some actionable guidance while also appreciating the complexity of all of this. I mean, this is going to publish in a couple weeks, like prior to the new year, everybody's thinking about their New Year's resolutions. I'm sure there's a lot of people watching or listening who are thinking about how they're going to try to finally.

lose that extra 10 pounds or whatever it is. But they're also, you know, on the precipice of all kinds of social gatherings where there's going to be lots, their food environment is going to be less than ideal. And, you know, what is your, what is your counsel to the average person who's trying to navigate their food environment, make better choices, and have a, you know, a better understanding of what's really going to drive sustained weight loss and better health outcomes over the long haul. Yeah, yeah. So I think a couple of points.

Well, one is one that I think people, again, too often tie to weight loss, but the effects are, especially acutely, but the effects are in, you know, the positive effects are completely independent and that's exercise. Too often people around the new year and they kind of come up with some New Year's resolution to join a gym or start an exercise program or hire a personal trainer and they tie their success to what's happening on the scale. And that's, I think, completely misleading, right? Because even if you don't lose a pound or even gain a pound, if you become regular in your exercise habits, both, you know, your function, your day-to-day function, your ability to kind of get around and move about in the world as well as many metabolic consequences are independent of how much weight you lose. And so I think that's one factor is that people should not tie their success at exercise with what happens on the scale. And I think that too often we do this, especially in that New Year's time.

One of the things you talk about in the book and in your work is that not all fat is equal. Like, there is a distinction between problematic fat and, you know, I guess what you would call like healthier fat. So just the number on the scale or how much like adipose tissue you have doesn't really tell the whole story about your health or lack thereof. That's right. Yeah, exactly right. And it's the function of your fat as well as where you're storing excess calories, and if you're storing it outside of your fat tissue, your adipose tissue, if it's in your muscle, for example, or in your liver, then that's the problematic areas. And exercise is potentially beneficial for both of those things, even if the overall adipose

tissue doesn't change or change its functional. So, yeah, visceral fat is a little bit, it's one of those popular bad guys that people talk about, but I don't think there's really good evidence that visceral fat per se is bad. So, visceral fat, again, is adipose tissue. It's a small amount that's around your organs. It's not actually in your organs. And, you know, there's some evidence to suggest that it's really not contributing as much as we originally believe to poor metabolic health. Yeah, because I've always thought, oh, well, that's the bad one.

I mean, it's the one you're not, you don't even know if you have it necessarily. Yeah. I mean, and it tracks a little bit more closely with liver fat than subcutaneous fat. it's still a little bit debated about how relevant visceral fat is, per se, to metabolic health. So, for example, if you do bariatric surgery and at the same time, you remove visceral fat, you can just take it out, a huge chunk out. And therefore, you don't see the same sort of people talk about it dumping into the portal band of the liver and having inflammatory properties. is you get rid of that, the meta-analysis suggests you're no better off having your visceral fat removed from a metabolic standpoint than you are from just getting the bariatric

surgery. And in fact, if you cut up subcutaneous fat, you don't get any of the metabolic benefits of losing weight, right? So there's something special about weight loss per se that doesn't have to do with the surgery. It doesn't have to do with the visceral fat or even subcutaneous fat per se. So it's more likely to be the fat that's in your muscle cells, in your liver cells around your pancreas that are the more problematic areas. But the point is exercise is beneficial metabolically, regardless of whether or not you're losing weight, regardless of whether or not you're losing this. It's such a boring answer.

It is a boring. It is. Behind the velvet rope, you know, Kevin. Yeah, yeah. It's like, oh, exercise? Yeah, she never heard that before, right? But I think the new part, I don't know how new it is. But the new part is that people, they tie it so closely to weight loss about whether or not they're succeeding.

Or it's the reason for doing it. The reason for doing it, right. I mean, the benefits for weight loss don't seem to show up acutely. They show up later. Maintenance of weight loss is pretty closely tied to how physically active you are. So it seems like you're saying don't obsess on weight loss, focus on, you know, eating healthier foods and exercising. And improving metabolic health. That's right.

And you can do that, yes, fat loss can help with that. But, you know, whatever you're going to do to change your lifestyle or change your, to actually lose weight, you've got to be willing to do that permanently. Because I think, again, that's one of the things that people have this idea that, well, I'm going to go on a diet to lose weight in a new year. And then once you do that, everything's great. Yeah, exactly. Put your foot off the pedal. I mean, after studying the biggest loser contestants and all, I mean, you must have learned, quite a few things about the difference between, you know, people who are able to sustain

healthy habits and, I mean, this gets into psychology, obviously, but, and those that lapse. Right. Yeah. I mean, so, no, I didn't learn. You didn't. Okay. Some people do and some people don't. I'm a little bit of a bonehead in that regard. I tend to look at things, you know, if it's not happening in the hypothalamus or the reward regions of the brain. I'm like, that's too much cognitive. That's a messy psychology. You're not for a soft science. Yeah. Okay. So, yeah, some people might learn a lot, not me.

But yeah, I mean, I think it's really interesting, though, because I think that, again, one of the chapters of the book we talk a lot about sort of precision approaches, like you're the unique snowflake and there's huge variability in the amount of weight loss that people have. And if only we could identify, you know, what special biological properties you have that would promote weight loss in a given intervention, I don't think there's good evidence. for that yet. And the presumption seems to be that there's some magic biological driver about who's a success story and who's not. But I think that, again, getting to the softer sciences of this, whether or not you have a supportive partner or supportive family, whether

or not you have the economic means to kind of make these changes and change your local environment in ways, which I think you can. People do have some agency to kind of change those kinds of things. Those are going to be much more important. then, you know, signing up for the latest, you know, CGM gut microbiome analysis, which is, in my view, vastly overhyped at the current time and being oversawled to people. There's some evidence of that that we present in the book that, you know, these things are not as reliable as they're being made out to. Yeah. I mean, I think there are tools like anything else. I think they lack adequate amount of education as a sort of, you know, central piece to it. and the technology isn't quite there to provide the best, you know, kind of actionable recourse as a result of these. And I think that the data points, you know, there's so many data points now with all these wearables and it's disorienting.

And you don't know what's important and what's not. And so you're making health choices based upon short-term, you know, data reports that don't necessarily mean anything and can potentially drive, you know, poor decisions around. That's right. Especially with CGMs. Like you see these spikes and you think, oh, well, the solution is just not eating anything that's going to spike my insulin. So it's like, all right, well, you can just eat fat all day long. It's probably not great, but you're going to have a nice line, you know.

Right, right. Yeah, no, that's right. And I think that the problem that I have is that the foundational science hasn't been done, right? So the measuring isn't there. So, I mean, one of the studies we did, especially when we have like this complete control over people's environments and, in fact, the order of the meals and the timing of the meals, we know all of this about the subjects that we had on, we would basically have two CGM simultaneously, one on the abdomen, one on the arm as according to the manufacturer's instructions. And yeah, the results that you get

are correlated, but you have this huge variability where the same people simultaneously eating meals, one is rock solid and the other one is causing a spike. If they were accurate within a certain, you know, like reasonable range, would you have a different opinion on that? Because it does seem to me like anything that connects you more deeply with the habits and the choices that you're making and can kind of show you evidentiary proof of like what you're doing and what is doing to you is probably a good thing. It can be a good thing if you know how many times you have to measure the thing to have a reliable response. And our data suggests that that's probably more like 10 times, right? Like if you measure the similar responses to the same food

or same meal 10 times, then you probably have a pretty reliable response. And that's even in the highly controlled situation. I mean, that's true of everything. I mean, just as an athlete, like, wearing heart rate monitors. Like, I know if I, my chest monitor is always going to be more accurate than whatever's on my wrist. Right. It doesn't matter of the sensor.

But even if all I have is a wrist sensor, I know that that number isn't exactly accurate, but if I do it over time, like, it's more, it's the variability in that number that still provides me with some value. And I think that knowing that. and having done that sort of research and advances what's lacking in this particular space, right? So, and instead what you get is you get people who see something on just a couple of occasions, you know, they see their blood sugar spike eating a banana, and they do it like on two or three occasions, and they think, oh, that's my response to bananas is.

And what if that person really loves bananas, right? And it's not really a reliable response because they haven't done it enough time. And they're going to eat bacon instead. And they eat bacon instead, and you've made their life measurably worse because they don't enjoy the bananas and potentially from a health-wise worse because they're now eating bacon instead of bananas. But I think these things, I mean, listen, you know, as human beings, we like little shiny bells and whistles and these things are fun. But, you know, the, the, you're like a pillars guy. And it's like, listen, just stay away from the ultra-processed foods, try to better control

your food environment. You know, when you go to the grocery store, stick to the far aisles where, you know, it's real food and, you know, exercise and get out. Like all these other things are like, you know, they're like cherry on top of the Sunday. sort of things. They are, and they can be distracting, I guess, is the point. And I think the other thing is when it comes to ultra-processed foods is that it is an extremely broad category, right? So the way it's defined academically. How do you draw that distinction? Because I often think, like, okay, so I wear a whoop tracker, right? And I love it, and it's great. And, you know, I look at the data points over a broad period of time. Like, I don't get caught up in every single day or whatever, but it has a little diary function. And it's like, and you can choose which little, like, checks things, and it's like, did you eat too late at night? Or, you know, did you eat processed foods? And I'm like, well, I had some olive oil and I had some, you know, like, is that a processed food? Is that not a processed food? What's the difference between a processed food that you might consider healthy and an ultra-processed food that is just

off the table? And what I'm adding is that not all ultra-processed foods might be off the table either, because it is, even within that category, as defined academically. So there's this Nova classification system. Basically, it groups foods into four different categories, and it has nothing to do with their nutritional properties, which is kind of a lot of the Kirkfuffle about ultra-processed foods is it doesn't talk about saturated fat or sugar or sodium or anything like that, or even fiber. But you've basically got whole foods. You can wash them, chop them up, freeze them, all sorts of things. You know, your produce, your even canned produce would be considered a minimally processed food as long as it doesn't contain certain preservatives and that are kind of more technologically

advanced. These are the minimally processed food. So eggs, meat, poultry, fish, produce, legumes, rice, those kinds of things. Then you've got processed culinary ingredients. These are the things that I like to think of as you don't eat them on their own, olive oil, right? No one's guzzling olive oil. This butter.

I think maybe Stephen Gundry is. Oh, that's true. Maybe true. Anyway, go ahead. I use the butter example, too, but my youngest child actually did eat like half a stick of butter once. Don't some of the carnivore people do that? Maybe they do. Anyway, either of that, the edge cases.

My son and the carnivore people. And a sugar would be another example, right? But the point is that you are using these so-called processed culinary ingredients to mix with category one, minimally processed foods, to create meals or preserve them or enhance. their sensory qualities. And in fact, that's the definition of category three, which is called processed foods. So breads, pastas, fermented products, these would all be called processed foods. And then basically everything else is what's called ultra-processed foods.

And so these are typically using a lot of these cheap agricultural inputs, things that you would not find, ingredients that would not be found in restaurants or home kitchens. You're often using processes and manufacturing methods that are not commonly used, things like extrusion technologies and all sorts of other kinds of things. Preservatives. Preservatives. Also, some categories of preservatives, if they belong to like a kind of a very historical way of preserving, like fermenting is a preservation technique.

That belongs in the sort of processed food category. But yeah, other kinds of preservatives, cosmetic additives, flavor additives, those would would count as something as ultra-processed. So within that category, all the kind of typical junk food type things, much of the fast food that we have, but also things like whole green breads that you buy at a supermarket, things like many of the plant-based meat replacements would be ultra-processed foods. A lot of things like some flavored yogurts and things that many people think are probably beneficial for health.

So it's an incredibly broad category of foods. And the question is, you know, it was an empirical question for a long time is our diet's high and ultra-processed foods connected, linked with diet-related chronic disease. I think that everybody realizes the answer to that is yes, they are linked. Mechanistically, how that works is still not fully understood. I think a lot of it is probably downstream of obesity, right? Something about this category of foods causes people to overeat calories and gain weight and become, have excess body fat, and as a result, having many of the downstream complications,

which kind of overlap with many of the things that ultra-processed foods have been linked to, obesity, type two diabetes, cardiovascular disease, several forms of cancer, and all-cause mortality, in fact. At the same time, you would probably also say, like, if you're ultra-processed food of choice is very high in sugar, and then you have type two diabetes, maybe there's a connection there. Yeah, yeah, yeah, yeah, absolutely. That extends beyond purely, you know, obesity or if you like salty stuff and you have high blood pressure. Yep, yep, that's true.

That's true. So there are independent mechanisms. And there's also, I think, one of the strongest areas of independent mechanisms are in gut dysbiosis and in gut function and the immune system and inflammation. There's a really interesting study that was connected by Kevin Whelan on people with Crohn's disease and removing ultra-processed foods and improving symptoms of Crohn's disease. So I think that that aspect is probably another clear area or certain amulsifiers in ultra-processed foods might exacerbate gut health, especially in conditions like Crohn's or maybe inflammatory bowel syndrome. So, yeah, that's another independent pathway. But, yeah, so I've been mostly focused on the obesity side of things and trying to figure out, well, what is it about diets high and ultra-process foods that might be driving this process? And that's kind of led us down to a couple of different areas.

One was how quickly these foods are often eaten. That tends to drive people to over-consume calories. Folks like Kieran Ford and Kays de Graff have shown that textural-based properties of these foods, they tend to be softer, easier to chew and swallow. Maybe by the time, you know, you've got the signal that you've eaten so many calories, it's already too late because you've eaten them so quickly. I think that's in the oral sensory properties of doing that, I think, is part of the story. But I think it's not the major story. I think the major story is the fact that these foods tend to be, they have their food matrix disrupted and they tend to be dried up. So in the ingredients that are used, drying them out is important for shelf life and microbiological safety, right?

The bacteria grow less well in dry environments. But in that process, in removing the water, essentially, from the foods, you're also concentrating the calories. You're increasing its so-called energy density. So the number of calories you get per bite of ultra-processed foods tends to be quite a bit higher, even if the amount of fat isn't any different because fat is often considered because it has twice the calories per gram compared to carbs or protein. Often we think of high-energy-dense foods as being high in fat. Well, actually, they can just be drier, less water. and that's another way to concentrate the calories. I think that's driving most of the effect,

and we've designed a study where we have people consuming a diet that's still 80% calories from ultra-processed fruits from this broad category, but we lowered the energy density of the diet. Typically by diluting it with fruits and vegetables and legumes and things like that, but still having most of the calories coming from ultra-processed foods. And when you do that, people eat many, many fewer calories and they don't over consume calories. So that's at least one factor.

So thinking about how calorie dense the foods that you're purchasing are and how you're incorporating them into meals, I think is a really important consideration. The other property that we've kind of looked at is whether or not there are combinations of nutrients that exceed certain thresholds together that you typically don't find in nature, so-called hyper-palatable foods, foods that are either high in fat and sugar, or or fat and salt, or carbs and salt, both together, they also seem to drive people to consume more calories. And so by focusing on these two aspects,

I think you can get at most of the effects of ultra-processed foods on over-consumption of calories. So just a lot of things for policy makers, if you wanted to sub-categorized ultra-process foods that are potentially problematic from a overeating standpoint, you should focus on those two properties, hyper palatibility and calorie density. If you're a shopper, it's harder, right? Because they have to take your calculator out. Yeah, but from a consumer perspective, it's sort of like, was it Oliver

Wendell Holmes? Who wrote the Supreme Court opinion about obscenity? It was like, you know, you know it when you see it. It's like it's impossible to define. It's like, like everybody knows, you know, oh, like you kind of know it when you eat it. You know, it's like, oh, can I not stop? Can I only have one and walk away? Like I think that's probably a pretty good rule for anybody. That is a pretty good rule. But me, I would have Imagine there are not so great ultra-processed foods out there that are counterintuitive. Like, oh, I thought this was healthy. And now I just realized, like, this is actually, you know, it's so much more colorically

dense than I realized or, you know, it has all these dark matter chemicals in it, as you say, or something like that that I wasn't even aware of. Or alternatively, there's probably also some foods that many people would all agree are ultra-processed, but are probably perfectly fine. Like, what would one of those be? Yeah, you put me on the spot. I don't know. But now I'm going to be recommending people eating ultra-present.

I mean, I think that many of the whole grain breads that you can get that have preservatives in them that would categorize it as ultra-process was that those would be some examples. But the truth is, and you know this, like, you know, everyone's obsessed with protein. We didn't even talk about protein. That's like a whole other podcast. It's a whole chapter. It's like, whatever. I know. But, you know, we're so focused on the wrong.

things. It's like, you know, protein, like we're not really, you know, having a crisis of people like not getting enough protein if they're just eating a variety of foods in their diet. But what we are having a problem with is people getting enough fiber in their diet. And if you were to just focus on that, like how can I increase my fiber intake by, I don't know, 50% or 60% or 70% into the new year? Wouldn't that solve a lot of problems for people? Or is that too reductive? It is too reductive. I'll tell you what. Because in our ultra-processed diet studies, people ate the same amount of fiber. Because we gave them fiber supplements.

And it didn't change the fact that they ended up. It's interesting. Because I know when I, the more that I, like if I make sure I'm eating a lot of fiber, then it just crowds out room for eating the other things. Yeah, you're getting it mostly from whole foods. Yeah, I mean, when I say fiber, that's what I mean. That's what you mean, right? So that's different, right?

So there's multiple forms of fiber, right? But the way we sort of set it up in our studies, I mean, these folks are eating 50 grams of fiber a day in both diets. In one case, it's coming from mostly from a fiber supplement. And yeah, you've got lots of ultra-processed foods now that are adding fiber to a supplementary fiber to their, you know, sugar candy bars. Right. And so, yeah. Which is like greenwashing. I mean, you talk about that also.

It's sort of, that's problematic, the fortification of processed foods. Right. And you see the same thing with protein. We see the same thing with fiber. the same thing with people talking about low-carb cookies and whatever. So they attach this something that in most contexts might be beneficial for the people who are trying to eat according to that dietary pattern. And then they've created these products that seem to fit within that dietary pattern

based on some reductive thing like fiber or like protein or something like that. And so I think that's kind of what we're seeing here. And in fact, that's kind of what we did in our study, right? did the simple thing, which is, oh, if I'm going to focus on fiber, I'm going to give people a fiber supplement. We'll get fiber up to 50 grams a day, and that's what they ate. And, yeah, it didn't have the positive benefits that... What if they had to eat celery or, like, just something like, you know, whole food?

Right. Well, that's the point is that in the minimally processed diet, that's where they're getting the fiber. And in fact, yeah, that's a big contribution. And it's correlated with things like energy density, right? So these high fiber whole foods tend to be, have lots of water associated with them as well, right? Low calorically, yeah. Yeah, so these things kind of tend to go together.

And so that's another problem in nutrition science, right, is that you have these things like food is not like one thing, right? So you say, well, was it the fiber? Was it the low calorie density? Was it the phytonutrients? It's infuriated. There's no end of the amount. You could, whatever randomized control truck, you're never going to be able to, like, how are you going to be able to, like, how are you going to to solve this problem.

I think the point is that we have to make incremental progress. I mean, one of the things we say in the book is nutrition isn't rocket science. It's harder because of these substitution problems. If you use real foods, you kind of got to think about, you know, whatever you replaced it with in your study, the fact that, you know, there's still all of these things about foods that we don't even, we haven't even identified what's in them, the nutritional dark matter that you talked about, whether or not they're important for health is still an open question. So, yeah, I mean, you could throw up your hands and say, we know nothing, but that's not true, right?

We do know a lot. And we're making incremental progress. And I would say, given the anemic funding that nutrition sciences had over the past several decades, we've actually made quite a bit of progress. But, yeah, there's a lot more to do. And I'm excited about participating in that science in the future and figuring some of these things out. But we're not going to figure it all out. We have to kind of prioritize our list of topics of what's the most important. thing to recognize. And I think that that's where reductionism can come into play.

I'm intrinsically as a physicist, a reductionist, of thinking, well, yeah, if we could solve this part, we'll get to like 80% of the effect. And then we'll work on the rest of the 20%, which will probably be five or six things contributing to that smaller effect and just sort of breaking out what is the most important question and most important effect to kind of account for. My view is that right now, one of the most important effects, that we need to understand is what is it about different food environments that causes people to consume vastly different amounts of calories, and how does that impacting actually our biological systems that are regulating body weight? Because, I mean, it's still just

amazing to me, right? And we've seen this over and over again, not just in humans, but in animal studies over and over. You just shift their food environment in certain ways, and without trying they spontaneously choose to eat very different numbers of calories and regulate at a very different body weight we need to understand that and I think we're making progress I mean that's consistent with the blue zones findings you know it's it's not about individual choice it's about like where you live and is that environment conducive to health not just in terms of the food that that is within arm's reach but you know is it a place where you have to walk a lot and

you're engaged in some kind of low-grade activity throughout the day and you're in a community and there's a faith-based aspect to that, like all of these factors. Like, you can change the food environment, but there's also the psychological factor and, you know, like how you share love through food and all the, that's where it gets, you know, it just, it just mushroom clouds into like a million variables. Yeah, health isn't just about food and it's not just about metabolic health, right? It's all these other things as well. So if you were going to design, like what is this?

the ultimate study that you would like to perform? If funding was not an issue and it was all green lights all the way, what is the randomized control trial or what is the study that you would construct to help you answer the question that you're trying to answer? Yeah, I think it's multiple, again, it's multiple parts of research, the research community working together, right? We don't have the ability in humans to measure the kinds of things that we can measure in, for example, animal models and mice in particular to kind of manipulate neural pathways and measure specific populations of neurons. And people are making a lot of progress there, but we do need the parallel human studies

to measure and manipulate food environments in very controlled ways and observe how they affect. How do they affect different kinds of people, living with their families, for example. And that's why what we were proposing was a facility to be able to conduct those kinds of studies. And controlled manipulations of the food environment writ large, not just the foods that you present to somebody. on a plate. But the overall marketing of foods, the experience that they have on how frequently people are, you know, buying foods in restaurants versus preparing them themselves in their, you know, local apartments, research apartments or something like that. How can we actually do studies where we can do very practical experiments manipulating the food environment to see

what policies might actually be effective, right? Like we talk a lot about policies like menu labels and whatnot in front of packed labels. And we do a little bit of analysis of that. But we don't really do randomized control trials of that in small populations of people. Does a warning label actually work? Right. Well, people do investigate some of those things in isolation. But what I'm talking about is what if we had like a community of people where they would come

and live with us for a month or two, right? And we would switch up, you know, in a cafeteria-like setting, you know, the prices of different items or the quantities that we were giving to people or change the formulations of those items and periodically measure physiological functions and biomarkers and whatnot and really try to understand what changes in the food environment, kind of in this broader sense, are actually contributing to people's behaviors. That's almost like creating your own Truman Show. Yeah, sort of.

Like these people where everything they interact with, you know, is a very, that you're controlling. That's right. But I think that the interesting thing is I think that that kind of study would be a lot more humane than the kinds of studies that we've been doing so far, where people basically come and live in a hospital ward for two months sometimes, isolated from their families, right? But you could have envisage a way of doing this kind of research that is actually more comfortable and enjoyable for participants and is developing a much richer data set that you could have as

you know, you could clearly still have your primary outcomes as being, this is the main point of the experiment, but we're exploring a whole lot of other things simultaneously in ways that were previously just free variables. And now we're able to kind of control them. And get better answers to these kinds of questions and enroll different people from different patient populations and different ages and different parts and stages of life. Yeah, I think that it would just be an incredibly useful resource. And so the specific trial, I think, is less important than the ability to do these kinds of studies. And what would we need in order to kind of do that?

And we're not talking about billions of dollars. We're talking about tens of millions of dollars to create such a facility. The way I sort of think about it kind of going back to my physics days is physicists don't have, you know, 20 different particle accelerators around the world and everybody has their own little unit. They build a big one. And the people who have the best ideas for the best experiments, basically submit grants to conduct those experiments at that facility. We need the equivalent of the big particle accelerator for nutrition research. And if we did, for human nutrition research, if we did, I think we would get answers to

these questions a lot more efficiently. There's got to be a billionaire out there who's like, yes, this is what I want. But for him, it's like buying a Starbucks, here you go, you know what I mean? I think we all want these answers. Yeah. And I feel optimistic and confident that, you know, somebody's going to foot the bill for something like that because these are answers that we all want.

The work that you're doing is vital. And I'm certain that you're going to find your next spot. And I want you to be able to do all of this research because, you know, the world needs you, Kevin. And I appreciate you coming here and talking to me today. Thanks so much. Yeah. So everybody check out food intelligence.

I'll link it up. in the show notes. And if anybody wants to learn more about you, where would you direct them? I guess website, Kevin Hall, Ph.D.com. Yeah. And more will be revealed about where you're going to go next. Indeed. We'll figure it out. Well, please come back and talk to me again. I really appreciate you coming here today. Thanks, my pleasure. We'll do. Peace.

All right, everybody, that's it for today. Thank you so much for listening. I really do hope that you enjoyed the conversation. To learn more about today's guests, including links and resources related to everything discussed today, visit today's episode page at richroll.com, where you will find the entire podcast archive, as well as my books, Finding Ultra, the voicing change series, and the plant power way. If you'd like to support the podcast, the easiest and most impactful thing you can do is free, actually. All you got to do is subscribe to the show on Apple Podcasts, on Spotify and on YouTube, and leave a review or drop a comment. Sharing your show or your favorite episode with friends or on social media is, of course, awesome as well and extremely helpful. So thank you in advance for that. In addition, I'd like to thank all of our amazing sponsors.

Without him, this show just would not be possible, or at least, you know, not free. To check out all their amazing product offerings and listener discounts, head to richroll.com slash sponsors. And finally, for podcast updates, special offers on books and other subjects, please subscribe to our newsletter, which you can find on the footer of any page at richroll.com. Today's show is produced and engineered by Jason Camello, along with associate producer Desmond Lowe. The video edition of the podcast was created by Blake Curtis and Morgan McRae with assistance from our creative director, Dan Drake, content management by Shana Savoy, copywriting by Ben Pryor. And of course, our theme music, as always, was created all the way back in 2012 by my stepson's Tyler and Trapper Piot, along with her cousin, Harry Mathis.

Appreciate the love, love the support, and I'll see you back here soon. Peace, plants.