Calories Are Down. Exercise Is Up. So Why Is Obesity Exploding?

Episode Overview

• Family Physician, Functional Medicine Doctor, and #1 NY Times Best-Selling Author (Food Fix, Eat Fat, Get Thin) Dr. Mark Hyman (a former physician at Cleveland Clinic starting in 2014 and co-founder/affiliated with Function Health) interviews Dr. Dariush Mozaffarian, MD, DrPH—a Cardiologist educated at Stanford (biology), Columbia (MD), and Harvard (MPH, PhD/DrPH in public health, nutrition, and epidemiology), who serves as Director of the Food is Medicine Institute at Tufts University, former Dean of the Tufts School of Nutrition Science and Policy, and author of Food is Medicine: Healing Our Bodies, Nourishing Our Minds, and Transforming Our Food System.
• The episode traces how the modern food system was created over a 100-year period (shifting rapidly in about 30 years mid-century) to solve vitamin deficiencies and mass starvation, inadvertently creating a chronic disease crisis where 94% of American adults have suboptimal cardiometabolic health (hypertension, glucose, body mass, etc.), only 6% have optimal cardiometabolic health, and 10,000 Americans die every week directly from poor nutrition.
• The speakers dismantle outdated nutrition paradigms—including "eat less, move more" calorie counting, low-fat dogma, the protein-isolate craze, and fear of seed oils—by explaining how food quality controls resting energy expenditure, gut microbiome calorie absorption, and natural GLP-1 signaling.
• Finally, the conversation explores how "Food is Medicine" policies can redirect a fraction of the nearly $6 trillion US healthcare budget into healthy food prescriptions and federal nutrition programs to transform both human health and the economy.
• Disclosed episode sponsors read by Dr. Hyman include Cozy Earth (apparel and bedding, 20% off at cozyearth.com/hyman), Made In Cookware (5-ply stainless clad cookware, 10% off first order at madeincookware.com with code HYMAN-HIVE), Fatty15 (C15:0 supplement, 15% off a 90-day subscription Starter Kit at fatty15.com/HYMAN with code HYMAN), Pique Life (Sun Goddess Matcha and Kara Marine Collagen, 15% off for life at piquelife.com/hyman), Paleovalley (100% grass-fed Bone Broth Protein, 15% off first order at paleovalley.com/hyman with code HYMAN), and BIOptimizers (Magnesium Breakthrough Advance 10, 15% off at bioptimizers.com/hyman with code HYMAN).

Key Concepts

• The Medical Education Gap and the Scale of the Food Crisis: Despite completing 15 years of post-high school training (4 years college, 4 years medical school, 3 years internal medicine, 4 years cardiology), Dr. Mozaffarian received zero true nutrition education beyond basic biochemistry like the Krebs cycle and ATP. Around 2000, he realized cardiology's focus on fat, saturated fat, and LDL cholesterol was mistaken—hedging later in the episode that heart disease is "probably not even about saturated fat anymore because it's much more complicated"—and instead pointed to the Lyon Diet Heart Study in France, where a Mediterranean diet lowered heart attacks by 62%. Today, food is the #1 cause of poor health, economic devastation, and environmental destruction, killing 10,000 Americans weekly and costing the US economy at least $1.5 trillion a year (closer to $2 trillion adjusted for healthcare inflation, or $15 trillion over 10 years) in healthcare spending and lost productivity.
• How Solving Starvation and Deficiencies Built the Modern Food System: Modern nutrition science began in 1932 when Vitamin C was first isolated and synthesized. Previously, vitamin deficiencies caused mass death: scurvy (Vitamin C deficiency) killed more sailors in the 18th and 19th centuries than anything else at sea, night blindness stemmed from Vitamin A deficiency, rickets from Vitamin D deficiency, and pellagra (niacin/B-vitamin deficiency) afflicted 3 million Americans and killed 100,000. After President Franklin Delano Roosevelt's 1941 national nutrition conference led to enriching processed wheat flour, these deficiencies were largely eliminated within 10 years. Next, as world population quadrupled from ~1.5 billion in 1900 to 6 billion in 2000 (approaching 9 billion today), 1950s/1960s demographers (like the Stanford professors behind The Population Explosion) predicted up to a billion people would starve. The Rockefeller Foundation backed plant geneticist Norman Borlaug, who spent 10 years in Mexico breeding wheat, rice, and corn for starch yield using WWII DuPont DDT, leftover bomb-factory ammonia nitrogen fertilizers, and intensive irrigation. Yields rose 1,000% to 2,000% (10- to 20-fold) per acre, turning Mexico, India, and Pakistan into food exporters in 5 years and saving 1 billion people—but leaving humanity getting ~60% of its calories from roughly 5 monocropped starchy plants (and Americans eating 500 more calories of corn per person than in the past).
• Industry Manipulation and Ultra-Processed Foods (UPFs): Convenience food was pushed into home kitchens starting in the late 1950s/1960s following a General Mills meeting in Minneapolis (e.g., Betty Crocker) and corporate infiltration of high school Home Economics boards to teach cooking from packaged foods. In the 1960s, the sugar industry paid two Harvard nutrition scientists the equivalent of ~$50,000 to publish a New England Journal of Medicine review blaming fat instead of sugar for heart disease. By the 1980s, low-fat dietary guidelines forced companies to replace fat with sugar, emulsifiers, and stabilizers, while tobacco giants Philip Morris and RJR bought major food brands (Kraft, Nabisco, General Foods), holding them for 10 to 20 years and deploying addiction and youth-marketing scientists to engineer addictive products. Defined in 2011 by Carlos Monteiro in Brazil (NOVA classification), UPFs now make up 50% to 60% of US calories (compared to ~20% in the next highest country). While Dr. Mozaffarian hedges that there is heterogeneity among UPFs (an ultra-processed yogurt or whole grain may be better than soda or candy), nearly 100 long-term observational studies over 15 years link UPFs to chronic disease even after adjusting for salt, sugar, and saturated fat, and three randomized controlled trials (lasting 1 to 8 weeks) matching macros showed UPFs drive overeating and weight gain.
• The Calorie Paradox, Thermogenesis, and the Microbiome: While unpacking the exact biological details is ongoing, objective data (including doubly labeled water studies) shows that since 2000, US calorie intake has stayed flat or declined and physical activity has increased, yet obesity has surged. Food quality dictates energy balance through two mechanisms: First, over the last 20 years, population-level Resting Energy Expenditure (REE) has dropped by 220 calories per day because low-fat, ultra-processed diets blunt brown fat thermogenesis (which is activated by protein, high-fat/ketogenic diets, and polyphenols like quercetin, blueberry compounds, and green tea EGCG). Similarly, a clinical feeding trial by Dr. David Ludwig showed people on a low-fat diet burned ~400 fewer calories per day than those eating identical calories on a low-sugar/low-starch diet. Second, on a traditional minimally processed diet, humans absorb ~80% of calories while the gut microbiome consumes ~20%; on an ultra-processed diet, humans absorb 98% of calories, starving the microbiome and creating a 500-calorie daily swing on a 2,500-calorie diet.
• Gut Metabolites, GLP-1 Signaling, and Innate Food Intelligence: Although natural GLP-1 produced by the intestines lasts only minutes in the blood, fullness lasts for hours because a healthy microbiome converts whole foods into metabolites that enter the circulation and activate GLP-1 receptors. Roughly 25% of circulating signaling molecules in human blood come directly from the microbiome, and another 25% are altered by it (50% total). When patients take GLP-1 drugs (as documented in a New York Times Magazine article), they spit out "fake"-tasting Ho Hos, Twinkies, candy, and soda, and naturally crave cherries, kale, vegetables, and fish—mirroring a 1920s Canadian orphanage study cited in Fred Provenza’s book Nourishment, where children offered whole foods (including brain, kidney, and liver) innately selected what they needed for growth. Furthermore, Tufts research quantified that more chronic disease is caused by insufficient intake of protective foods than by excess intake of bad foods.
• The Protein Myth and Metabolic Conversion to Fat: The average American consumes 16% to 17% of calories from protein, which already matches the "high protein" group in clinical strength-training trials. While both doctors hedge for edge cases—such as younger and older women eating little animal food, older adults with anabolic resistance, or Dr. Hyman himself needing extra protein (including whey shakes) and strength training at age 65 to rebuild 25 pounds of muscle lost to a catastrophic back infection—90% of Americans already get enough protein for normal strength training. When people consume excess protein (especially ultra-processed soy protein isolates in junk food) without lifting weights, muscles reject the circulating amino acids, causing insulin to rise and convert that excess protein into body fat.
• Seed Oils, Trans Fats, and the Omega-6 vs. Omega-3 Reality: Dr. Hyman notes he used to believe seed oils were "evil" before Dr. Mozaffarian convinced him they are mostly a bystander/biomarker of ultra-processed food. Historically, industrial vegetable oils were partially hydrogenated, creating toxic trans fats until the FDA banned them in 2018 after a 20-year delay (modern Crisco uses fully hydrogenated oil, which lacks trans fats). The theory that omega-6 polyunsaturated fats cause inflammation came from molecular theories and animal models by scientist Bill Lands, but human trials show omega-6s are not pro-inflammatory. While Dr. Mozaffarian concedes that heat and chemical extraction introduce trace toxins—making virgin oils "probably better for you on average than industrial oils"—countless human randomized, observational, and feeding trials show industrial seed oils (especially soybean and canola oil, which contain plant omega-3s) are net beneficial for health. A poor omega-6 to omega-3 ratio is caused by an omega-3 deficiency—which Dr. Hyman notes affects well over 50% of Function Health members tested at Quest Diagnostics—not an omega-6 excess.
• Healthcare Economics and "Food is Medicine" Policy Levers: US healthcare spending rose from $1.6 trillion in 2000 to $5.6 trillion last year and nearly $6 trillion this year—costing $50,000 annually per average family of four, consuming nearly 20% of GDP (10-fold more than the 2% of GDP spent on AI and data centers), and taking nearly 35% of every federal dollar. Meanwhile, total US food spending is ~$2 trillion, and federal nutrition programs (SNAP, WIC, school, elderly, and childcare meals) receive nearly $150 billion a year. Currently, 30 US states are testing Food is Medicine in Medicaid alongside the VA, Indian Health Service, and Medicare Advantage; while Dr. Mozaffarian notes there is "no single number" for current healthcare spending on food, he estimates it at least at $10 billion. Redirecting just 3% to 4% of the $6 trillion healthcare budget into healthy food prescriptions and medically tailored meals would inject $240 billion into the healthy food market, driving a systemic transition comparable to clean energy (now 25% of US energy and nearly 50% in some European nations).

Quotes

• At 0:04:26 - "How the top cause of poor health facing many patients is missing from healthcare. And that's a pretty big sentence, a pretty big statement, that's pretty important and actually explains so much of the mess we're in with rising healthcare spending and people getting sicker every day." - Dr. Mozaffarian explaining how 15 years of medical training omitted nutrition, leaving doctors unequipped to treat the root cause of chronic disease.
• At 0:10:53 - "One of the messages of this book, which I think is really important, is that food is the single biggest problem facing humanity. Period. You know, I'm not saying it's among them, it is the single biggest problem facing humanity, and it's fixable." - Dr. Mozaffarian framing the central thesis of Food is Medicine across health, economic, environmental, and social dimensions.
• At 0:12:26 - "We have shown that 10,000 Americans die every week directly from poor nutrition, mostly from chronic diseases like diabetes and heart disease and other, you know, obesity. That's three September 11ths every single week." - Dr. Mozaffarian quantifying the weekly American mortality toll from diet-related diseases.
• At 0:23:36 - "Yields of wheat, rice, and corn went up 1,000 to 2,000% per acre, right? Not doubled, not tripled, they went up 10 to 20-fold in just a handful of years. And so Mexico and then India, Pakistan went from countries that were on the brink of starvation to food-exporting nations in five years." - Dr. Mozaffarian describing how Norman Borlaug's Green Revolution prevented mass starvation while flooding the global food supply with cheap starch.
• At 0:33:43 - "So calorie intake has gone down or is about the same as 2000. And physical activity has gone up since 2000, not a lot, we're still as a nation, you know, under-exercising, but it hasn't gone down since 2000, it's gone up. ... So we have a paradox: physical activity's gone up, calorie intake is flat or has gone down, and obesity has dramatically gone up since 2000." - Dr. Mozaffarian using population data to disprove the conventional "eat less, move more" model of obesity.
• At 0:36:40 - "These studies have shown that over the last 20 years, at a population level, our resting energy expenditure has gone down by 220 calories per day. That's more than enough to explain the obesity epidemic, right? We're doing everything right, everything we're being told to, but our resting energy expenditure has gone down." - Dr. Mozaffarian revealing how modern diet quality slows down basal metabolism and brown fat thermogenesis.
• At 0:37:54 - "If you have a true kind of traditional minimally processed diet, we digest and consume about 80% of the calories, and the microbiome digests and consumes about 20%. ... In the modern, you know, ultra-processed diet, 98% of calories are consumed by us, and we're starving our microbiomes. So that's another 20% of calories. If you're eating 2,500 calories, we're talking about a 500-calorie swing in how many calories you're digesting versus your microbiome." - Dr. Mozaffarian explaining why intact whole foods result in fewer absorbed calories than ultra-processed foods of the exact same caloric value.
• At 0:39:20 - "So he said it's not how much you eat that you should pay attention to, it's what you eat. So if you pay attention to what you eat, you don't have to worry about how much you eat." - Dr. Hyman summarizing how focusing on food quality naturally regulates appetite and energy balance without calorie counting.
• At 0:42:15 - "About 25% of all the circulating signaling molecules in the bloodstream are directly from the microbiome, and about another 25% are altered by the microbiome. So you're talking about 50% of our signaling molecules directly produced by or altered by the microbiome. It's another organ that's affecting our mood, our behavior, our brain, our diet, our appetite." - Dr. Mozaffarian illustrating how gut bacteria act as an endocrine organ that sustains GLP-1 fullness and regulates cravings.
• At 0:48:41 - "More disease is happening, Mark, and we've quantified this, more disease is happening and is occurring because of insufficient intake of good things than too much intake of bad things. It's both, but there's more disease from people not eating enough good things." - Dr. Mozaffarian emphasizing that adding protective whole foods is even more critical for preventing chronic disease than just avoiding junk food.
• At 1:01:01 - "If you eat excess protein and you have the amino acids circulating in your bloodstream, the muscle says, 'I don't need them, you didn't work out in the last couple days, you know, I don't need more amino acids.' What happens? Insulin goes up, the counter-regulatory hormone insulin, the same hormone that regulates, you know, glucose, goes up and turns those amino acids into fat for storage in the body. So protein gets turned to fat." - Dr. Mozaffarian explaining the metabolic fate of consuming high-protein shakes, bars, and isolates without resistance training.
• At 1:10:32 - "This is the key point: countless studies, randomized trials, carefully done studies, observational studies, feeding trials, have shown again and again and again that industrial seed oils, net, are still really good for our health." - Dr. Mozaffarian refuting social media claims that omega-6 seed oils cause human inflammation and disease.
• At 1:13:32 - "When people talk about the omega-6 to omega-3 ratio, yes, if you have a high ratio of omega-6 to omega-3, it's really bad for you, but it's because your omega-3s are low. Trying to fix the ratio by moving the omega-6 isn't going to do anything; you got to move the omega-3." - Dr. Mozaffarian clarifying how to properly address an imbalanced fatty acid ratio.
• At 1:19:35 - "For the average family of four, we spend $50,000 a year on healthcare. ... One in five dollars that goes through our pockets goes to healthcare, way bigger than all the money that's being spent on AI and data centers and all that. All the money the country's spending on AI and data centers is about 2% of GDP. ... We're spending almost 20%, 10-fold more on healthcare than everything we're spending on AI." - Dr. Mozaffarian highlighting the massive economic burden of US healthcare spending and the financial leverage available for Food is Medicine programs.

Takeaways

• Shift from calorie counting to minimally processed, polyphenol-rich foods: Instead of restricting calories—which fails when ultra-processed foods lower resting energy expenditure—eat intact, minimally processed foods (including polyphenol sources like blueberries, green tea, and quercetin-rich foods) so your gut microbiome consumes up to 20% of your calories, activates brown fat thermogenesis, and produces natural GLP-1-sustaining metabolites.
• Prioritize adding protective foods, not just eliminating junk: Because more chronic disease stems from a lack of protective foods than an excess of harmful ones, focus your daily diet on increasing nourishing whole foods alongside cutting out ultra-processed items.
• Expect rapid, staged health improvements when changing your diet: Use dietary upgrades (such as eliminating ultra-processed foods, sugar, gluten, and dairy when clinically appropriate, as in Dr. Hyman's patient whose rheumatoid arthritis resolved in 10 days) to improve your microbiome, energy, mood, and sleep within days; blood glucose, blood pressure, and cholesterol within weeks; and diabetes or heart disease risk within months to a year.
• Pair protein intake with regular strength training: Avoid eating excess protein without exercise, as unused amino acids trigger insulin and turn into body fat; perform strength training at least 3 times a week for at least 30 minutes (increasing protein strategically if you are an older adult facing anabolic resistance, recovering from muscle loss, or a woman eating few animal products).
• Upgrade your protein quality using a four-tier hierarchy: Choose plant proteins and seafood first; yogurt, cheese, and fermented dairy second; fresh animal foods (eggs, poultry, and regeneratively grown or pasture-finished red meat) third; and strictly avoid processed meats with chemical nitrites/sugars (bacon, salami, bologna, low-fat deli meats) and ultra-processed protein isolates added to junk foods.
• Fix your fatty acid ratio by boosting omega-3s rather than fearing omega-6s: Test your Omega-3 Index and increase your intake of omega-3-rich foods (like fish/seafood), and if you want to avoid the trace chemical/heat toxins found in industrial oils, opt for virgin oils while recognizing that oils like soybean and canola oil provide beneficial plant omega-3s.
• Use culinary enjoyment to crowd out ultra-processed convenience foods: Reclaim home cooking from the packaged-food industry by preparing delicious, minimally processed meals at home rather than relying on engineered, addictive convenience products.
• Support and utilize "Food is Medicine" healthcare and federal programs: For policymakers, clinicians, and patients, leverage Medicaid waivers (now active in 30 states), Medicare Advantage, the VA, Indian Health Service, and federal nutrition programs (SNAP, WIC, school meals) to prescribe and fund medically tailored meals and healthy groceries.