Published 22nd October 2026
How to use food as medicine to reverse disease in months: The top 5 foods for living longer with Dr Dariush Mozaffarian
Share this article
In this episode, leading cardiologist and Director of the Food is Medicine Institute, Dr. Dariush Mozaffarian, explains how modern diets increase your risk of heart attacks and why standard medical advice often falls short.
Dariush examines how past dietary guidelines have shaped today’s food system and why shifting the focus to whole, protective foods improves your health.
He also explains why counting calories fails, shows how ultra-processed foods took over our food supply, and asks whether saturated fat deserves its reputation as a cause of heart disease.
Through the idea that food is medicine, you’ll learn how to adopt healthy eating habits by identifying protective foods, forming practical diet shifts that can control your blood sugar, lower cholesterol, support your gut health, and cut your risk of heart attacks and strokes.
By the end of this episode, you'll know what to add to your diet to prevent and heal disease, using the idea that food is medicine.
Try our science-backed and tasty wholefood supplement Daily30
Let your gut microbes snack on the ZOE Gut Health Bar
Build healthy habits. Download the ZOE app today 👉 Join ZOE
Follow ZOE on Instagram.
Jonathan: You're a doctor. Do you believe that food is medicine?
Dariush: Yes.
Jonathan: Can changing what I eat drastically reduce my risk of a heart attack even if I've been eating badly for 50 years?
Dariush: I'll give two words. Absolutely, yes.
Jonathan: Is all saturated fat bad for health?
Dariush: No.
Jonathan: Do most of us need to eat more protein?
Dariush: No.
Jonathan: Do you consider ultra-processed food a health risk?
Dariush: A significant health risk, absolutely.
Jonathan: And finally, what's the most common mistake that people make when thinking about food as medicine?
Dariush: Breaking down, food into negative aspects of things they should avoid, calories, salt, sugar, rather than sort of celebrating the bounty of nourishing, delicious, healthy food.
Jonathan: Nutrition advice in general, government guidelines in particular, get a huge amount of flack, and there seems to be this almost constant debate around them, and so it's interesting that you're so strong and clear, and yet many of those topics are a bit of a minefield. And I think many of us feel that if experts can't agree, you know, how am I supposed to know what to do? Why is it as a cardiologist you're so focused on nutrition?
Dariush: Well, this was something that, you know, came to me naturally from my training. You know, four years of medical school, three years of internal medicine, four years of cardiology. Throughout that 11 years, it was more and more obvious that nutrition was a major issue facing my patients. You know, maybe the top issue. If they didn't smoke, it was the top issue facing them. And yet I wasn't learning anything about it in 11 years of training, and so that was kind of a first big shock to my system, that one of the top causes of poor health that I was seeing in my patients wasn't being addressed in healthcare. This was in the 1990s at the height of the low-fat diet fetish when everybody was eating low-fat everything. And so I started reading the science myself. I said, "Well, I should educate myself then if I'm not gonna learn from my training." And when I started reading the science myself, I was shocked, Jonathan, that even then in the '90s, the science didn't support a low-fat diet. And so that was the second big shock, that the science we had wasn't actually being translated into policy and recommendations. And so that set me on a course to really understand the science and translate the science to patients.
Jonathan: I'm interested that here you were thinking about heart health, and you went straight to nutrition because I think a lot of people jump to smoking or, like, not enough exercise and that unless you're doing something really terrible, that nutrition is, like, a long way behind those two things as you're thinking about looking after your heart.
Dariush: Well, so it wasn't just heart disease because as a cardiologist, you're thinking about diabetes. You're thinking about strokes in the brain. You're thinking about obesity, you know, all the risk factors, blood pressure, cholesterol, glucose, inflammation, all the risk factors we were learning about. And as I looked at the world of what, you know, was influencing health, the gap between what was being addressed in healthcare and how important it was largest for nutrition. So certainly smoking is a problem, although today there are more deaths globally from poor nutrition than from smoking. Still smoking is a big problem, but smoking was being addressed in healthcare, right? There are lots of things. There are drugs. There are smoking cessation clinics. Doctors talk to patients, you know, screening about that. Physical activity is also an issue. It's not as big of an issue just numerically for health as nutrition because we all eat three times a day every day. But it is also important, but also even physical activity was being addressed. You know, there's cardiac rehab, there's physical therapists, there's thinking about that. But if you take the gap between what we're doing now and where we should be, for human health and also as we can talk about for the economy and for the environment, there's nothing that approaches nutrition in terms of the gap between what we are doing today and the opportunity. So this opportunity to change health, at a scale of millions or billions of people, is incredible for nutrition. And so that kind of really galvanized me and excited me and made me really want to dive in. And what's incredible is that gut feeling, which was just a gut feeling, has now been, you know, really validated by research papers from us and from others that what we eat is the top determinant of health for around the world. And so if you care about health, if you're in healthcare, if you care about your own health, nutrition has to be the top thing you think about. Not top three, not top five, the top thing that you think about.
Jonathan: Can I ask about this food is medicine statement? Because it's quite a strong statement, isn't it? You could say food is really important for your health, but I think when we think about medicine, we're used to this idea of almost this sort of transformational power of taking this little pill or maybe these days the idea of like an injection. Are you overstating things when you say food is medicine?
Dariush: Absolutely not. So people think of food as energy, calories. People think of food as vitamins. People think of food as, you know, building blocks, like maybe protein. But food is much more than that. Food is really biologic information. It's biologic information that alters every physiologic pathway in the body from the brain to the gut to the inflammatory and immune systems to blood pressure to actually the function of your genes inside cells. And so everything we eat is really code, biologic information that alters all of the pathways in our body. And so it dominates our health for good or for bad. And the concept of food is medicine is more than just that general concept that food is important for health. It has a few other principles, I'd say. Another principle is that we're not saying food is poison, we're saying food is medicine. And for too long we've approached nutrition as a battle of deprivation, as a battle against bad things in food. Don't have salt, don't have sugar, don't have fat, don't eat anything that's good for you, don't eat too much. And we've really-- the word diet almost, you know, has a person think of austerity. And food as medicine is about celebrating the good, celebrating protective foods, which, you know, I'm sure we're gonna talk about, Jonathan. Foods that actually nourish health. We need to embrace more of things. I think that's really key. And I think a third principle about food as medicine is that this isn't something that takes decades to work. This isn't only about an ounce of prevention is worth a pound of cure. Certainly, it's true that nutrition in pregnancy, in the, in infancy, throughout life is important decades down the line, but food can have immediate effects within days or weeks on our mood, on our energy, on our, on our physiology. You can reverse diseases sometimes within months with healthy food. So it truly is treatment. And then I think the last thing I'll say as the leader of the Food as Medicine Institute is nowhere in any of this are we saying food is only medicine. The word only is not in that phrase. And so food is also culture and joy and dignity and family and taste. Food is many things, but it is also actually medicine.
Jonathan: You said that it doesn't have to take decades to work. You can actually reverse some diseases in just months. Could you tell me a bit more about that?
Dariush: Sure. And so back to your first point, I think that's really worth emphasizing, and we've shown this quantitatively. If you look at the disease burdens around the world of major diseases, whether it's cancer or heart attacks, strokes, obesity, diabetes, any major disease we've looked at, in every single case, there's more disease burden quantitatively from healthy foods that are missing from the diet than from, you know, bad things that are in the diet. And so both, of course, contribute. You know, we have to take out some things that are, that are bad, particularly salt. We can, we can talk about that. But there's more disease due to good food missing from the diet, insufficient intake of healthy foods. And that's what's so amazing because that's a positive message for consumers. It's a positive message for food industry. It's a positive message for farmers. It's a positive message for governments who are trying to support the farmers in their countries. We need to be building a system that supports more healthy, nourishing, delicious food, and that will actually improve our health, improve our rural economies if we're supporting local farmers, lower healthcare spending. It'll basically reverse what we have now, which is an extractive food system.
Jonathan: And if you look at this, 'cause I know you like to look at this at a population level as well as then what does this mean for individuals, if we can improve the diet of everybody, like how many lives could we save each year?
Dariush: Well, we've looked at this both globally and also in the United States. I'll just use the United States as an example, but many of these numbers are similar in every country globally. We've estimated that almost half of all cardiovascular disease events, heart attacks and strokes, are directly attributable to poor diet and would be preventable. Almost half.
Jonathan: Almost half of all heart attacks and strokes- Yeah... Are directly linked to diet.
Dariush: If people had reasonable healthy diets, not the absolute perfect diet, but reasonable healthy diet, basically following guidelines, we could prevent 45% of heart attacks and strokes. For diabetes, that number jumps to 70%, 70% of diabetes, and that's globally actually. We've looked at that globally. It's a little bit higher in the United States, almost 75%. 70% of diabetes around the world, type 2 diabetes, could be prevented if people had healthy nourishing diets. And, you know, those two conditions together, right, are the dominant cause of poor health in every country on the planet. There are case studies of people with severe autoimmune diseases who've had them for years and tried multiple cocktails of medications and never been able to resolve their symptoms, and have gone on healthy diets and within months have seen their symptoms go away. Of course, that's not gonna be true for everyone. Gut health conditions, right? People who have irritable bowel syndrome and other conditions, ulcerative colitis, sometimes changes in diet can dramatically reverse them. And so these are really major conditions that are causing enormous suffering and being treated with pharmacology instead of with just what nature intended, which is, which is healthy eating.
Jonathan: And Dariush, on those autoimmune examples, I feel like for a very long time, individuals would tell these stories about how, you know, the medical system was failing them. They took their diet into their own hands, and suddenly they were much better, and this was met with an immense amount of skepticism by doctors. So I'm really interested. You know, you're a physician. You believe in drugs and medicine and things like this, I assume.
Dariush: Oh, of course, yeah. I'm a cardiologist. I practice here in downtown Boston and, you know, some we have a lot of life-saving drugs that are important.
Jonathan: There is, however, something real here, you're saying in those examples about the food really meaning that people can basically end, you know, very serious symptoms related to these autoimmune diseases in some cases?
Dariush: Yeah, and I've seen this myself with psoriasis, with rheumatoid arthritis, with eczema with conditions, a lot of atopic or allergic conditions often related to an abnormal gut and leaky gut and inflammation due to different insults in different people, but people have been able to go on elimination diets and actually cut out particular foods and understand what's harming them. This isn't new knowledge. You know, healers for millennia have known that food is really important. So in some ways we're rediscovering old wisdom.
Jonathan: I think that historically there's been this sort of big divide, hasn't there, between doctors and anything that's to do with nutrition, in the same way maybe there's been a divide between, like, the brain and the body. And one of the reasons this seems to have shifted is this realization that, you know, the gut microbiome is important, that your gut health is important, and so we have a better understanding. Maybe mechanisms which should explain this rather than it sort of being too magical perhaps for, you know, the medical profession to be able to take it seriously?
We don't buy the hype — and neither should you
Our new app reveals what the food labels won't, using data from the world's largest nutrition study run by ZOE.
Dariush: Yeah. And this gets to you know, how we got here today and how the science has progressed, how the history has progressed. And in my book, Food Is Medicine, in the first part of my book talks about this history of how we got here. And I have a lot of books I've seen or read that talk about the modern food system, and many of them sort of roughly start in the 1980s with the rise of ultra-processed food and talking about big food as like big tobacco and all of these other things and that industry's making us sick and there's a lot of truth to those stories, but that's not really where the story starts. First is how new all of this is. So we didn't have an obesity epidemic in the United States in 1995. I mean, there it had started to creep up in the late '80s. It was starting to go up, but this wasn't something we discussed or learned about. And so really, this is not only something that's happened in our lifetimes, this has happened in our adult lifetimes. This incredible explosion of diet-related disease has happened in about thirty-five years, and it's happened at different rates in different countries, but it's pretty much happening globally. And so those two facts that something has happened incredibly rapidly and fairly uniformly or at least, you know, consistently across the world really suggests there's just a handful of things that have changed, right? There's not thousands and thousands of things that have all exactly changed in exactly the same way in every nation and every community and every socioeconomic structure. And so you have to step back and say, "What's changed? What has happened?" And what's fascinating to me is if you go back and look at the history, is what we have is a twentieth century food system that was built for twentieth century priorities that actually did a great job of meeting those priorities, but now we have twenty-first century problems, and we have a mismatch. The other interesting fact that most people might know is how young nutrition science is, modern nutrition science. Modern nutrition science, I would date the birth of modern nutrition science to 1932, less than 100 years ago. That date, 1932, was when the first vitamin was discovered, isolated, and synthesized. So, you know, we think, oh, we think about germ theory and all these other things. We didn't even know about vitamins till the late 1920s and the 1930s. There was, there were epidemics of these deficiency diseases like scurvy or these other conditions, epidemics of them around the world, and people thought they were infectious diseases. People were sent to Indonesia to discover what was causing beriberi, what bacteria was causing beriberi and killing people. So really, 1932 was the, was the actual first real birth of this idea that there's something in food that causes disease, and it shocked people. It shocked people. People were amazed by it. And the accident of history is that birth of vitamin science, which really, these were significant diseases. You had 80% of kids sometimes in the UK, in poor areas in New York, in poor areas in Australia and Egypt that had rickets, you know, vitamin D deficiency and bowed legs and bone you had, you had vision problems from vitamin A deficiency, right? These were, these were endemic conditions in most countries. And so the accident of history is this birth of vitamin science and kind of this explosion of vitamin science corresponded with the Great Depression and World War II. And so now you had science on deficiency diseases that could be hurting populations correspond with true threats to world food and world shipment of food. And so in the United States President Franklin Delano Roosevelt heard about this new science and knew we were going to war, and so in 1941, before the US had entered the war, though Europe was in war, before the attack on Pearl Harbor, he convened the National Nutrition Conference for Defense. That's the name of the conference.
Jonathan: The National Nutrition Conference for Defense-
Dariush: For Defense...
Jonathan: Was the first ever nutrition conference?
Dariush: Yeah, and that's what led to the RDAs, the Recommended Daily Allowances, those numbers you see on the backs of packages. They didn't exist because we had no concept of these molecular compounds in foods and what they were and how much we needed.
Jonathan: And Dariush, why was this conference for defense?
Dariush: Well, because he saw the science, and we actually had instituted a peacetime draft as well to start to build up the troops, and he saw the science that people were unhealthy, and actually the one of the number one reasons that otherwise qualified Americans were being rejected for the draft was poor teeth because of poor nutrition, because of vitamin deficiencies. And so he saw this was a threat to national security, and so he convened this conference. He said, "What do we need to have a fit population that's healthy for war?" And if you read his introduction, why he's convening the conference, it's amazing. He says, "We know that poor nutrition is important for a fit population to go to war and be ready for national security." And so that led to this kind of change in how we think about food as from before the 1930s and 1940s, it was, "Well, eat a balanced diet, you know, get food from different food groups," and that's all people knew, to, "Hey, look, we can identify the specific compound in a food- That causes or cures a disease. We can identify what the population needs. We can set an RDA, and we can deal with it. And so that led to vitamin-fortified flour, vitamin-fortified milk, all these, you know, supplemented foods. And within 20 years, 30 years, vitamin deficiency diseases were eradicated in high-income countries, and dramatically reduced around the world. So this was an incredible success, and we have to mark it for a success. But it also led to this reductionist approach to food, that if we understand the nutrient, we can sort of recreate even better than nature healthy food. And there's a, there's a remarkable statement about the vitamins lost when whole grains are processed to refined grains in this national nutrition conference. They recognize, they say, "Oh yeah, when you take a whole grain and you process it and you turn it into refined starch, you're losing all these vitamins." And so they recognize this, but instead of saying, "Hey, maybe we should stop processing the food so much," they said, "Oh, let's just put the vitamins back." And so it was almost a hubris that we can recreate a perfect food through technology and through supplementation. So that was one big wave from the 1930s to the 1950s. The second big wave that really determined our 20th century food system was a fear of famine, not enough calories, and there were two driving forces for that. The first was the actual experience of World War II. Almost 30 million people around the world died of famine during World War II, more than all the troops that were killed in battle. Shocking devastation. And if you adjust for the world population, that'd be like 100 million people dying in a few years, you know, in today because of famine. Equivalent of
Jonathan: 100
Dariush: Million people dying- Imagine-...
Jonathan: Of not having enough food.
Dariush: Imagine in like the next three years, 100 million people around the world die. People were just horrified by this, by the suffering. And then demographers and others were looking at this population boom after the 1920s. More people were born in the 20th century than in all of prior human history combined. We went from about one and a half billion people in 1900 to six billion people in 2000. We quadrupled the population. We added four and a half billion people. And agriculturalists did the calculations. They said, "We look at the acreage of farms, we look at the output per acreage, we look at the population, a billion people are gonna starve by 2000." There were, there were these books written and predictions of doom. These were very real fears. And so the Rockefeller Foundation got together with the United States government and the government of Mexico and said, "Let's try to do something about this," and they got an agricultural expert who was working at DuPont at the time, his name was Norman Borlaug, and said, "Please go to Mexico." And he said, "No, I have a family. I'm not gonna do this." They said, "Please, please go. Please go." They finally convinced him, and he went to Mexico, and he started this program to see if he could increase the yield of crops. And ultimately, this led to the, what's called the Green Revolution. And so Norman Borlaug basically put together over 10 to 15 years of pain... It took him 10 or 15 years. Painstaking work. He did plant breeding of different species, focusing on wheat, and he found exactly these particular species that he bred that could have incredible yields of starch. They were, you know, resistant to different kinds of conditions. But then when they had these incredible yields, they exhausted the soil very quickly when they were just planted over and over again. So he said, "I need to have a fertilizer." And there were all these bomb-making factories that had all this ammonia. They had incredible ammonia production. So he took the nitrogen from these bomb-making factories and created synthetic nitrogen fertilizer. And then he said, "Oh, we need to deal with pests." And he had worked on DDT and knew about DDT when he was at DuPont, which was discovered during World War II to protect the troops, a pesticide from typhus and malaria. And he said, "Let's spray DDT on the fields. That'll get rid of the pests." And then he also incorporated high-flow irrigation. And so in a matter of decades, what he did was he increased the yield per acre, the yield of ultimately wheat, rice, corn, by 15-fold from modern agriculture, right? You take a highly bred single species crop, you monocrop it over and over again. You're exhausting the soil, so you put synthetic fertilizers down. You need synthetic pesticides because the plants are growing so much, and there's no more natural protection against the pests. You use intensive amounts of water. And it was incredible. We have more food today. We're able to grow more food today than we've ever been able to grow before. And India, after Mexico went from a food-importing nation to a food-exporting nation. India went from a nation on the brink of mass famine, in five years after introducing Norman Borlaug's Green Revolution, they were an exporter of wheat in five years. Pakistan, all of these nations. He transformed the whole food system, and now 60% or so of our calories come from a handful of these highly bred intensive crops.
Our new app gives you the power to see beyond the marketing
Make smarter, science-backed food choices in seconds. Scan. Score. Reveal the truth.
Jonathan: You're saying he saved potentially a billion people from starvation, which is good, and on the other hand, I'm struck by the way he took almost these tools straight out of the industry that had been built for World War II and, like, this mass industrialization and, like, this single approach and sort of applied it to food. And we've moved immensely far from the ways, I guess, in which we have always grown food before.
Dariush: That's right. You know, he won the Nobel Peace Prize for his work, and he, and I think he should have. I mean, he really saved countless lives with his work, and I think he was a true hero, but there were unintended consequences of what he did. And so now all of a sudden we're in 1980, and within, imagine within just a few short years, we've conquered vitamin deficiency diseases. We've conquered mass global famine and food from 1950 to 1980. I mean, it was unbelievable the innovation that went on in that time. And so now scientists in particular, and then eventually also governments and industry said, "Well, we've dealt with that. What's, what are the next problems?" And the problem that came onto everybody's list was heart disease because heart disease was the biggest killer in most developed countries. And so scientists started turning their attention to heart disease, and this really started in the '70s, the late '60s and '70s. And the mistake they made, the accident, was that they said, "Look, we know the recipe for fixing nutrition. We find the nutrient, we address the nutrient, and we deal with the disease." And that approach works beautifully for a vitamin deficiency disease where there's, like scurvy and vitamin C, where there's truly one vitamin, one nutrient that prevents or cures the disease. And so they said, "What is the cause of heart disease?" And they basically said saturated fat, right? That's the nutrient, and so we deal with it, we address it, we'll deal with, we deal with heart disease, and they broadened that to include total fat and dietary cholesterol. And so in 1980, the first in the United States, the first-- and the first really major global guidelines to focus on chronic disease. It was the first time really ever we'd had dietary recommendations focused on reducing chronic disease as opposed to these diseases of want. And that was the mistake. That was the mistake we made, and that led to the explosion of low-fat products. And to make low-fat and fat-reduced products, you have to do things to make them taste better. You have to add emulsifiers and stabilizers and thickeners. You have to add flavorings. You have to add gums. You have to add all this stuff to make a fat-free salad dressing or a low-fat yogurt or, you know, a low-fat other food. I think the line and story around vitamins and calories is quite clear and simple. I think for ultra-processing, there were other things, of course, you know, shelf life and low expense and so on. But that was a major determinant of what ultimately became ultra-processed foods. You had starchy, inexpensive ingredients that cost, you know, pennies per kilogram now, wheat and rice and corn, highly processed, and you had people saying, "Have low fat," which meant use more of those, and then you had to make those products palatable, right? You had to make those products palatable, and people were used to eating real food. And so now we had to take food that really wasn't real anymore and take its fat out. Absolutely right. And then when it really, I think, took a turn, particularly for the worse, was when, you know, two of the biggest tobacco companies in the world at one point owned almost all of the major food brands because they were flush with cash. They had so much money and they wanted to look for places they could, they could invest. And they said, and they said, "Food is a lot like tobacco, right? You can... You sell it to people. We know how to market it. We know how to do that." And so at one point, and so RJR, RJ Reynolds became RJR Nabisco, and almost every major brand you can think of, particularly in the US, was at one point owned by these two major tobacco companies. And they took the exact same marketing scientists and brain addiction scientists that they had working on tobacco and turned them onto food. So literally the same labs, the same marketers, the same folks that were studying addiction in the brain and how to hook people, the same people that were studying how to hook children on tobacco early, they took all those same teams and they turned them onto food.
Jonathan: Is this really true? Are you really saying that these tobacco companies both did buy all of these nutrition companies and they really did send over these scientists who were working on addiction and marketing to children? Like-
Dariush: It's all been documented in leaks or memos that have come out under lawsuits or leaked information. And all of this has been very well documented that they really intentionally, you know, tried to merge their approach to hooking people on tobacco, very much so with food. Now, I will say food addiction, I think, is a complicated concept. Tobacco is clearly addictive, but in what the average person would think of as addiction, I think it's fair to say food can be addictive. Ultimately, they realized they couldn't make that much money, and so they ultimately divested from many of these companies because they realized how competitive the space was and that food is not tobacco. So now it's no longer true that most of these are owned by tobacco companies. But there was a period of about 20 years where many of the major brands were snapped up by these, by these companies.
Jonathan: And so I guess to bring it back to the story that you started with about how when you first qualified as a doctor, it didn't really seem that there was an epidemic of obesity and ill health, and now it's clear, and you were tying it back to this shift. What was the impact of all these tobacco companies coming into these nutrition companies, and what does that mean for, like, the food that we've ended up with now?
Dariush: Well, the first thing I wanna say really clearly is I'm not 100% sure why the obesity epidemic started, and the fact that we don't fully understand it is just, is just shameful that we haven't been investing in the science. But I think there's lots of good science pointing towards why we have this, and again, these are issues I cover in more detail in my book, that I think there's big themes of why we have this rise of chronic disease. I think the first is the rise of refined starch. And so we know now that refined starch, wheat, rice, corn, potatoes that are highly refined, act in the body much like sugar, and in fact have a higher glucose response in the bloodstream than even the natural sugar. So that was a big driver of this. I think a second big driver is things that were stripped away and lost from the food. And so there are literally millions now, millions of compounds in foods that we have just starting to document and catalog and understand that have biologic effects. Not the handful of vitamins and handful of macros that we usually measure and look at, but compounds like cocoa flavanols in dark chocolate, or EGCG in green tea, or curcumin in turmeric, or sulforaphane or quercetin in vegetables. These are unbelievably powerful bioactive molecules. Getting back to food being biologic information. And also dietary fibers that feed our gut and those bioactives also feed our gut. Those were mostly lost and stripped away. And then you have all the additives, which I used to dismiss, Jonathan. I used to say, "They can't be that important." But more and more research is coming out that many of these additives actually affect the gut microbiome, affect health, affect the brain, affect development in children. And so while we don't know which one has the biggest problems and which are the worst and which are the best, I'm convinced that we don't know they're all safe. This, I think, is why we have chronic disease is these three things. Yeah.
Jonathan: And Dariush, can I ask for a minute about that? 'Cause it feels like there's sort of been two waves here, because one is this wave of very refined foods. This is what you're describing. You know, everything ends up being like white bread and white rice and potatoes and french fries, and a world with obviously a lot of added sugar. And then it feels like there's this newer wave, this thing we call sort of ultra-processed food that no one talked about, you know, 20 or 30 years ago, where I feel there is very much still a debate, including among nutritional scientists, about whether ultra-processed food, like that's real in terms of an impact on health, or is this just the same? No you know, the underlying food itself is high in salt and sugar and fat. I'd really like to understand your thoughts on that.
Dariush: You mentioned a couple of times, you said sugar and fat, and then you said salt and sugar and fat, and that has somehow become a rallying cry among public health experts around the world. And the UK traffic light has, you know, fat and sugar and salt, and black box warning labels in Chile and other Latin American countries have this. We are making a huge mistake by still focusing on fat as a negative. Fat is positive. We should be eating more fat, more fat in particular from certain foods. But we should not be talking about fat, sugar, and salt as a problem. We should be talking about starch, sugar, and salt as the problem. In the United States, about a third of calories is refined starches and refined grains. You know, that and salt. If we talk about the negative things in food, those are the two biggest negative things. Those are right now, today, completely tied up in ultra-processed foods. And so whether it's other aspects of ultra-processing or the molecularly disassembled starch, which we can talk about why the molecular disassembly is important, whether it's just the starch or whether it's these other things, I think it's probably both. And so it is a it is a, it is hard to disentangle, but as a class, you know, ultra-processed foods, which are the foods that are giving us these highly refined starches and salt and other additives, I think are definitely the negative problem. And then we've lost, to get back to what we started with, we've lost our focus on nourishing whole protective foods because we've gone to the cheapest possible calories, right? We had such success in the 20th century that their food scientists, even food scientists who had well-meaning, you know, well-meaning goals, believed they could create a better food, right? And so they said, "Look, I can make a bread that lasts for six weeks. It's cheap, it's inexpensive, and it has the right vitamins, and I'm making American families or British families or families in Australia healthy." And that was a mistake.
Jonathan: It's really interesting because I'm struck by the analogy between that and the way in which we designed our lives in terms of exercise and movement over the last 100 years, where I think, you know, our ancestors forever, like, labored in the fields and for, you know, probably wore their bodies out by the time they were 60. And so it seems completely normal to think, "Wow, we can escape from this." And only now we realize that if you live that life, you don't do enough exercise, it has this terrible impact on your health. And that funnily enough, if you're living in a city and you have to walk around a lot more, you're actually just healthier without anything else. And one of the things we've discovered is that, you know, our bodies are not only complicated, but they're sort of designed to work in an outside environment they evolved in. And so as we've moved too far away from that, you know, we've hit problems we just didn't even realize
Dariush: I love that you brought up physical activity, and of course, at an individual level, physical activity is critical for general health, and we all should be exercising more. But you sort of implied that perhaps this rise of chronic disease is, has been due to a decline in physical activity in the population. And this is where data matter and evidence matters. And so what's really fascinating is if you look in the UK and the US or you look across other countries, the average physical activity in cultures now living very traditionally kind of hunter-gatherer lifestyles or middle income countries or high income countries, the average physical activity is actually the same across all of those populations. And the physical activity over time in Europe and the United States has actually gone up since I was in medical school and training. So while we've had this obesity epidemic, physical activity has been going up, not down. More people are running, more people are going to gyms, more people are paying attention to their bodies. What's actually changed is not our physical activity as a whole, although again, it's poor. What's really changed is our food and the resting energy expenditure based on a range of new studies just published in the last couple of years, has gone down by about two hundred calories per day over the last twenty, thirty years.
Jonathan: What does that mean?
Dariush: For an average person, seventy to eighty percent of the energy we burn, the calories we burn, is at rest. Not of our activity, but just the background resting function of our brain, of our heart, of our digestive systems, when we're sleeping, when we're sitting, you and I are sitting now. That has gone down. Not our physical activity energy expenditure, but our resting energy expenditure. And there's more and more evidence that's directly tied to what we eat. We're not actually eating more, and that's causing us to be obese. We're eating poorly, and that's causing us to be obese, and it's actually driving down our metabolic rate, the energy we burn. It's driving down. And so while people are struggling and trying so hard to follow their calories and watch their calories, they're gaining weight because the food we're eating, the ultra-processed food we're eating, the lack of healthy protective nurturing foods, is actually driving down resting energy expenditure. And again, this is early science, new science, exciting science. If this is true, and again, I'm not a hundred percent convinced, but I'm in the... You know, this is where the evidence is going. This means our entire approach to treating obesity has been wrong, right? Telling people, "You're not exercising enough. You're eating too much." And we really have to focus on the quality of what we eat and how that interacts with our bodies and with our, even our energy expenditure. This has been seen within countries, like looking within the United States or within the United Kingdom, but it's also been seen across countries. And so if you compare high-income developed communities to middle-income communities to very traditional communities, again, physical activity energy expenditure is the same measured objectively using tools that like doubly labeled water, which measures energy expenditure objectively. But resting energy expenditure is lower. We're running cool. I think it's likely related to two major pathways. One is the microbiome, and the microbiome should be burning a lot of energy itself, and our, in our modern diets, we're starving our microbiome, and our microbiomes aren't burning the energy they should be. And the second one is something called thermogenesis, which is giving off of heat. So fat cells and muscle cells in the body can not only store energy or use energy for muscle movement, but they can actually give off energy in the form of heat. And so thermogenesis, for example, is what keeps a bear reasonably warm during hibernation. They have brown fat, which keeps them warm. Humans have brown fat as well. And so diet affects thermogenesis. And so I think through this loss of thermogenesis and through this dysbiosis of our microbiome, which Tim Spector in the UK has written a lot about, we are actually harming the energy we're burning.
Jonathan: Now these guidelines exist in every country, and they are hotly debated in every country. We're here in the US today, and there was recently an update to the dietary guideline for Americans, which I think was probably even more controversial than usual. And as a listener, I think that's really interesting whether you're in the States or if you're somewhere else because the US guidelines shape, you know, the biggest food companies in the world, right? Can we maybe talk about like what changes that are new here you think they've got right. And then maybe we could talk about, you know, where there are things that you would say should be different for someone thinking about, "Okay, I want to apply this for my own life."
Dariush: So the new dietary guidelines in the United States, which come out every five years, top line, I think they're great. I think they're the best dietary guidelines we've had since before 1980. They have... They're not perfect. I think there's challenges to them. So first, the things that didn't change. They continue to recommend low salt. Salt is a big risk for high blood pressure and stroke and gastric cancer and potentially even diabetes and other conditions. They continue to recommend, you know, eating plenty of fruits, eating plenty of vegetables. That's not changed. The biggest single change is the guidelines say to eat real food and to avoid highly processed foods, packaged foods, ready-to-eat foods, and they actually specifically call out a range of specific food groups that they say you should not avoid or limit these foods, sugar-sweetened beverages, cookies, crackers, you know, other packaged foods. You might say, "Well, that's not new. Dietary guidelines have been saying that for years." They actually haven't. Dietary guidelines for years, if the scientists say, "Hey, we should be eating more fruits and vegetables," the government loves that because they say, "Yes, that helps our farmers eat more fruits and vegetables." If the guidelines say, "We shouldn't be eating, you know, highly processed foods or sugar-sweetened beverages or things like that," the guidelines have hidden that under nutrient targets, and they don't say, "Hey, stop drinking soda." They say, "Limit your added sugar to 10% of calories," right? They don't say, "Don't eat bacon, processed meats." They say, "Limit your saturated fat to 10% of calories." Those nutrient targets give the implicit, and even one might say explicit, message that all foods are okay. As long as you're eating within your nutrient targets, there's no bad foods, and that's purely an industry message. There are bad foods. There are foods we shouldn't be eating, and there are foods we should be eating more of. And so this dietary guidelines turns that on its head and says there are bad foods, there are foods we should be limiting. It also says for the first time that Americans should greatly reduce refined grains. That's never been said before. And it also says for the first time that Americans should avoid foods that have artificial sweeteners, artificial colors, artificial preservatives, or artificial flavorings. Never before recommended. If you put all that together, refined grains, artificial additives, and highly processed foods, we're probably talking about sixty percent of food in the food supply our national guidelines are saying to no longer eat. That's big. And then on the positive side of what to eat instead, they're saying to eat whole grains, to embrace healthy fats. I love the word embrace. They say to embrace healthy fats, particularly fats with essential fatty acids, which are, you know, particularly plant oils. And they also say to eat more protein, which I think was a little bit of a mistake as we, as we started out with those rapid-fire questions, but isn't that big of a deal. And so really these are the first kind of real food guidelines telling people to avoid highly processed packaged foods, refined grains, and really embrace fruits and vegetables and minimally processed animal foods and whole grains.
Jonathan: So are there areas that you disagree with? And actually maybe we could start with that protein conversation and then maybe cover any others.
Dariush: Well, I think, I think in the rollout of the guidelines, the actual messaging from USDA and Health and Human Services from the US government has been really about the overturning the negative bans on sort of unprocessed red meat and whole fat dairy was another big change. I should have mentioned many European countries already don't focus on low-fat dairy. They say, you know, have-- Germany, Switzerland, the Netherlands, many other, many other countries in Europe already correctly say that whole fat dairy is fine, which is true. So these guidelines also say that. But the major messaging, I think around the guidelines has been like red meat is no longer in jail, whole fat dairy is no longer in jail. And so people have interpreted these guidelines as the eat meat and, you know, dairy fat guidelines. That's not actually what they really say. So I think, I think they've messed up a little bit in terms of what I disagree with the messaging. I think the messaging should have been more about the eat real food, not about, you know, these couple of minor changes. They did increase the protein requirement and the reason for that is to get reduced carbs. I mean, I had a chance to speak informally to folks in the administration, and they said, "Look, in schools and other places where the guidelines matter with a low protein target, the calories are filled in with starch or with sugar. And we really want to have real food go in there." So they say, "Eat more protein from real food," not protein supplements, not a highly packaged energy bar with protein, but from real food. And so I think they were intending that to address school meals and other places where they actually have to follow the guidelines. The protein target was increased from about ten to twelve percent of calories to about fifteen to twenty percent of calories, roughly. So it was increased, you know, considerably. On the one hand, it doesn't matter because the average American, and I assume the same is true in a lot of high-income countries, is already consuming around sixteen or seventeen percent of calories from protein, which is where the guidelines say we should be. So on the one hand, we're already meeting the target, and it's just increasing the target to where Americans are today. But the negative, I think, is that when people hear the word protein, the first thing they think of is red meat. Most people, right? Yeah,
Jonathan: I think that's right.
Dariush: And so I think that's the mistake. The guidelines actually say, if you read them, eat protein from a range of sources, from poultry, eggs, dairy, meats, fish, nuts, seeds, lentils, peas, beans, they-- soy. They list all of them and they say you should eat your protein from a range of sources. But people don't think that way. And so to me, that's I guess why I said it's not exactly accurate. We don't need more protein than we're, than we're eating now. But I think it's a mistake because it's gonna lead people to go for red meat. And red meat, unprocessed red meat is not the worst thing in the food supply, and there's worse foods. It's not the best thing in the food supply, but it's not something we should necessarily need to emphasize more. So I think that's what was a little bit of a mistake. They could have done a better job with that.
Jonathan: So I think what you're saying, Dariush, is in general, people are getting enough protein. But the thing that you, I think, have talked a lot about today is sort of how are you reducing the amount of refined starch? So this is all the flour and rice, but this is also your sugary drinks and things like this, and that you're actually putting that at the very top of your risk concern for what people are actually doing. Is that correct?
Dariush: That's right. So I think of food in a spectrum of kind of three categories. At the top are the protective foods that we should be embracing and eating more of. So that's minimally processed foods that are rich in fibers and phenolics and other foods that nurture us and our microbiomes, fruits, vegetables, nuts, seeds, beans, legumes, true minimally processed whole grains. All of those foods are just packed with healthy nutrients and phenolics and fiber. They're... Have natural intact structure, and the natural intact structure means they're digested slowly, and so more nutrition gets to our large gut, which is where our microbiome are. And so the speed of digestion, we think about the speed of digestion for the glucose response in the bloodstream, but what we're learning now is the speed of digestion is also important because if you digest everything quickly, then other than fiber, nothing gets to the large gut. And the large gut should be consuming not just fiber, but also starch and sugar and protein and fat that's in the food, that's in the natural structure. When it does so, first of all, it's a healthier, happier microbiome. It creates bioactive metabolites that go into the bloodstream and improve our health. But also it's actually digesting some of the calories. And so in a minimally processed diet, the microbiome might digest twenty percent of the calories we consume, whereas in a highly processed diet, the microbiome might digest just five percent of the calories you consume. And so you, Jonathan, could be eating a minimally processed two thousand calorie diet, and your own body, your own tissues, are only digesting sixteen hundred of those calories, and your microbiome's having a field day loving the other four hundred.
Jonathan: So you're saying if you go back to the sort of diets that we would all have been eating not very long ago, because all of this is sort of like whole food and the structure is intact, it's not just the fiber that's making its way unbroken down to my, you know, gut at the end of this long tube. But actually, interestingly, there would be like proteins and fats and carbohydrates that can also be food to my microbiome. But if everything is very refined, actually my body is sort of stripped out all of this stuff and nothing's making it through to, you know, my gut for my microbiome, except whatever little bits of fiber I would eat.
Dariush: That's right. And Rachel Carmody at Harvard is an evolutionary biologist who's done a lot of great work on this. Other, others have as well. We basically normally partition our calories, not just the fiber, between us and the microbiome. And so that's why we've evolved the microbiome actually to take that all the calories that we couldn't absorb and digest them and give us back some beneficial nutrients. That's why we have a microbiome. And now in the modern world with ultra-processed foods, that's one of the biggest hits to the microbiome is it's not getting any of that starch or protein or sugar or fat that it, that it should be getting. Too many calories for us, too few calories for the microbiome. If you look at a, you know, we've been grinding wheat for, you know, generations, but even at a microscopic level, there's still intact cellular structure, and so the bran is still overlapping the starch and slowing the digestion, and so some of that still gets to the microbiome. But in a, I mentioned this earlier, a molecularly disassembled food, a whole grain bread, commercial whole grain bread isn't a whole grain that's been ground up and turned into flour. It's endosperm, which is part of the grain, and bran, which is part of the grain, and germ brought from different factories from different parts of the world remixed together to resemble a whole grain, right? And so that is an... It has fiber. It's not terrible, but it's, but it's a molecularly disassembled food. And so for the really the ultra-processing, this loss of structure, I think is really important. So the protective foods are at the top, and I would add to those yogurt, which has live probiotics clearly seen to be linked to lower risk of diabetes again and again, and fish and seafood, which has omega-3s. Those are the most powerful, potent foods. In the middle I would say are minimally processed animal foods. And this is where I would put cheese and milk and poultry and eggs and unprocessed red meats, fresh red meats or frozen red meats, and butter. These are foods that are not as good as the protective foods, but they still have some benefits. They still have some nutrients. They're reasonable. These are the foods to eat in moderation. And so fermented milk, fermented cheese, probably a little bit at the top of that list of foods, and then poultry, eggs, butter in the middle, and then unprocessed red meats a little bit at the bottom of that list, not because of the fat in red meat, but because red meats are pro-inflammatory. There's pro-inflammatory compounds in red meat that's why red meats are linked to colorectal cancer and to diabetes in particular is pro-inflammation. So too much red meat can cause pro-inflammation. And then at the bottom, the third group of foods at the bottom, the ones to avoid, are the highly processed foods that are usually rich in starch, sugar, and salt, also processed meats, which are highly processed, and in other countries, not in Europe or the US, foods that have industrial trans fats and other, you know, significant additives. So these are the three kind of, you know, buckets of food. And so from a practical perspective, if someone says, "Look, is a red meat... Is red meat okay for me?" I have to say, "Compared to what?" If you're gonna go on a keto diet or a carnivore diet and you're gonna cut out processed starch and sugar, you're gonna be healthier, absolutely than if you're eating, if you're eating red meat. So you could eat red meat every day instead of starchy crap and you'll be healthier. But if you're eating red meat and not eating yogurt and blueberries and nuts and seeds and whole grains, you're actually hurting yourself. And so what I recommend to people is, if you like animal foods, go ahead and find minimally processed animal foods, but always eat them with the protective foods at the top of the list, the nuts and the seeds and the fruits and the healthy oils and other things. And don't eat them with other foods. So if you're gonna have eggs, don't add hash browns and white bread and bacon. Add spinach cooked with healthy oils and mushrooms and vegetables and then the egg becomes even healthier. And so to come back to protein, that middle category of animal foods is what most people think of when they think of protein. And so if people turn to minimally processed animal foods and eat more of that in place of starch and sugar, they're gonna be healthier. That's a positive. But if they think that more protein is just gonna build muscle without working out, right, they have a surprise coming for them. Because if you eat too much protein gets turned into fat by the body just like starch and sugar. And so don't think you can just eat your way to good health with protein supplements and protein shakes and high-protein Pop-Tarts and protein in your coffee. Don't think that's gonna get you to good health.
Jonathan: Yes. That is clearly the ultra-processed food that we were talking about earlier. Just to wrap up, because I wanna almost bring the circle back round to, like, your starting point as a cardiologist. There will be a lot of people listening who have gone to the doctor, had a blood test, and the doctor says, "Your cholesterol is looking high and you're on a path to do this, and you've got to worry about heart disease risks. And therefore you really need to avoid all of these saturated fats." And I feel the story we've been told is, like, saturated fat is bad and sort of unsaturated fat which tends to come from, you know, sort of plants and things like this is good. But you've already been saying, well, actually, yogurt might be quite good, but isn't that a saturated fat and in a way, I think you've been more positive about red meat than I was expecting. So could you just, you know, lay out your view around do I worry about these fats at all, and if so, you know, what's good and what's bad from your perspective?
Dariush: It's really clear that dairy fat is not harmful as a class. And so if you like whole-fat dairy, go ahead and have whole-fat dairy. More important probably to avoid the sugar. And so whole-fat dairy is fine. Saturated fat from plants, there's saturated fat in plant oils and plant foods, is also not a, not a big deal. You're getting so many healthy unsaturated fats. Unsaturated fats from plants are absolutely healthy, among the healthiest nutrients that you can consume. And then red meats, the saturated fat in red meats isn't really a problem either. Red meats in excess are harmful, but because of other factors, carcinogenic compounds, inflammatory compounds that... So really saturated fat is a distraction, just like total fat is a distraction. You could have a high-fat diet that's healthy or terrible. You can have a low-fat diet that's healthy or terrible. And the same is true for saturated fat. And so we have to move away from this, you know, 1930s reductionist focus that we developed when we were studying vitamin deficiency diseases. We have to move away from defining foods based on a nutrient and really think about their overall impact on health.
Jonathan: Even with somebody with a high result in terms of their cholesterol, you're not telling them to cut out these saturated fats. They're still allowed to eat full-fat yogurt.
Dariush: Well, it's not only the other things in the food, but the saturated fat itself has complex effects. And there's many kinds of saturated fat, so the saturated fat in dairy is not the same as the saturated fat in chocolate is the same as the saturated fat in red meat exactly. There's differences. And so yes, when I see patients here in downtown Boston with high blood cholesterol, the main recommendations I have for them is to increase healthy fats because from plant sources and seafood sources because embracing fats and stopping fearing calories and stopping fearing the, these harms of fats, healthy unsaturated fats from plant and seafood sources improve all blood cholesterol profiles, every single one that's measured. The second thing I might recommend to them is to have more minimally processed plant foods that have plant sterols. Plant sterols bind cholesterol, and can also lower blood cholesterol levels. And so having minimally healthy kind of Mediterranean style diet high in healthy fats is the best way to deal with blood cholesterol levels.
Jonathan: I would love to finish with one final question, and what I'd like to ask is, Dariush, if you had the power to change one thing about the current food system, what would it be?
Dariush: So if I had to change one thing, it would be let's start to prescribe healthy food for people so that doctors can write a prescription and for the right circumstances for the right patient. And not only will that improve health and lower healthcare spending, it'll also start to address health disparities because many times, while all of society's challenged with healthy eating, it's often people who are lower income or have less resources and just the struggle of affording healthy food is a problem. And so that would be my place to start.
Jonathan: I love it. I'd like to wrap up with a quick summary. I mean, the thing that- Stuck in my mind most is this amazing fact that American tobacco companies bought all of these nutrition companies. They basically owned all the big food companies, and then they had their scientists who were experts in addiction and their marketers who knew how to, like, push this stuff onto children basically work on food. The other thing I'm really struck by is we don't only need to feed our microbiome fiber, and that I think is generally the story that we talk a lot about. But actually, if you go back into the sorts of diets we were eating in the past, actually, because they were much more intact foods, sort of whole grains, things like this, they would actually get starches and sugars and fats, not just fiber. So they were actually breaking down a lot compared to the what they're getting today. And who knows? Maybe that is part of what links to what you're describing about the fact that we're just burning less energy in general. And so that's fascinating. I was then struck obviously by this amazing power of your description of food as medicine, and you said, like, half of all heart attacks and strokes are directly linked to poor diets. You said type 2 diabetes is reversible within months through food, and even people with sort of severe autoimmune diseases, many of them can reverse their symptoms with diet. The most important thing is adding more beneficial things into our food rather than taking things away, and so minimally processed fruits and vegetables, nuts, seeds, legumes, true whole grains. And on the flip side, what's interesting is you've been saying very clearly that there's been this obsession about fat, but from your perspective, that's just wrong. The key issue has been starches, sugars, salts, now ultra-processed food, and that critically, we had this amazing revolution that gave us all of these refined grains that feed us all. But it means it's become this huge issue for us as individuals, that all of our food is stuffed full of these things become sugars after we eat them, right? The rices and the flours and the potatoes. That's a much bigger issue for you than worrying about things like red meat or milks or butters. Actually, it's these, like, highly processed starches which are then ultra-processed into everything is, you know, the thing that we most need to worry about. But the replacement is eat more whole food.
Dariush: Yeah, that's a great summary, Jonathan, and the only thing I'd add to it is the optimism that we built this food system intentionally with intentional goals, particular around vitamins and calories, and we were extraordinarily successful. And so we can do it again if we have governments recognise the magnitude of the problem, we have science that's well-funded and can actually understand and the right directions we need to go, and then we have private sector innovation to tackle it. We can fix this all again within 10 years. I think we can completely turn this around if we have governments pay attention to it. And so let's have more information to people in the public and try to actually fix this.
