How to Upgrade Your Brain, Boost Metabolism, Maximize Hormones & Burn Body Fat with Shawn Stevenson

High-Level Overview

Lewis Howes welcomes back his friend Shawn Stevenson, host of The Model Health Show and author of Sleep Smarter, to talk about the ideas in his new book, Eat Smarter. Lewis starts with a personal question about the belly fat he has never been able to lose, and Stevenson uses it to open a long tour of how the body stores and burns fat: the five kinds of fat, where fat actually goes when it is lost, the hormones that act as gatekeepers, and why he thinks the calorie has become a kind of prison. He offers a five-part framework for what determines what a calorie does in a given body, argues that the diversity of the gut microbiome matters more than most people realize, and then widens the lens to water, omega-3 fats, fasting, supplements, the food system, chronic disease and COVID-19, and finally how nutrition affects patience and conflict in relationships.

The tone is high energy, funny and brotherly, full of St. Louis reminiscences and pop-culture analogies, and Stevenson cites a great many studies and statistics from memory. Those figures are reported here as his claims; the episode itself does not provide sources beyond his descriptions, and Lewis occasionally pushes for clarification. The centerpiece emotionally is Stevenson's own story of being told at 20 that he had the spine of an old man, and how changing one question changed his life. The conversation swings between physiology lessons, personal stories, practical tips and a larger argument that a healthier population would also be a kinder one.

The Discussion Explores:

• The five types of body fat, and why Stevenson calls fat an organ
• Where lost fat goes, and the hormones and enzymes that move fat in and out of cells
• The history of the calorie and five factors that change what calories do in the body
• The gut microbiome, food diversity, and why most Americans eat the same dozen foods
• Stevenson's recovery from a degenerative spine diagnosis through a "food first" approach
• Practical levers: leafy greens, omega-3s, olive oil, water, an eating window, and caution with supplements
• Chronic disease, the medical system's focus on symptoms, and COVID-19 outcomes
• How blood sugar and nutrition affect empathy, aggression and relationships

Deep Dive into Main Ideas

Five kinds of fat

Asked whether Lewis will ever lose his belly fat, Stevenson acknowledges genetics but points to epigenetics and says the first step is understanding what fat is, since most people are at war with something they do not understand. He describes at least five categories. Three are white adipose tissue, or storage fat. Subcutaneous fat sits just under the skin and is the kind you can pinch. Visceral fat, which he also calls omentum fat, lies deep in the abdominal cavity around the organs; he calls it the most dangerous type and the one most correlated with heart disease, Alzheimer's and type 2 diabetes. Intramuscular fat provides energy to muscles on site and resembles the marbling of a steak.

The other two burn energy instead of storing it. Brown adipose tissue is brown because it is dense in mitochondria, where he says fat is actually burned. Babies have a lot of it to prevent hypothermia; adults have less, mostly around the collarbones, shoulder blades and spine, and he says having more of it is correlated with better body composition. Beige fat can become either brown or white depending on lifestyle and nutrition. As one example he cites research in which coffee was found to encourage beige fat to brown, with brown fat areas lighting up on imaging, and a study reporting a 3 to 11 percent rise in metabolic rate from caffeine. He adds caveats: benefits follow a U-shaped curve, and quality matters, including what comes with the coffee.

Stevenson stresses that fat is not the enemy. Our ability to store and reuse energy helped make us human, and "Our fat is programmed to do what we've taught it to do." He describes fat as an organ in its own right that communicates across the body and produces its own hormones.

Where fat goes, and the hormones in charge

Lewis asks how he can wake up two pounds lighter. Stevenson says researchers tracked the path of fat leaving the body and found that about 84 percent is eliminated through the lungs as carbon dioxide, with roughly the remainder leaving through fluids such as sweat and urine. He says about a third of that happens during sleep.

He explains fat loss with a movie theater analogy. Fat cells are storage containers; you do not kill them, you get them to release their contents to be used as fuel. Two enzymes act as ushers: lipoprotein lipase ushers triglycerides into the fat cell, and hormone-sensitive lipase ushers them out. The pancreas directs them through two hormones he calls brothers. Insulin's job is to store energy, and it is essential for survival, as type 1 diabetes shows. Glucagon does the opposite, telling cells to release energy, but it cannot work while insulin is active. Carbohydrates and sugar drive insulin most, protein less so, and fat in a more indirect way. He says the average person eats around 150 pounds of sugar a year, keeping insulin chronically overactive until insulin resistance develops.

When Lewis notes that life expectancy keeps rising, Stevenson disagrees: "We're not necessarily living longer. We're dying longer." He claims life expectancy has recently ticked down for the first time in recent history. Lewis recalls David Sinclair making a similar point about staying healthy for as long as possible and then declining quickly.

The calorie as a prison, and five things that change it

Stevenson says calories matter, but that his nutrition education treated them as the warden of diet. He traced the history: the calorie began in physics and engineering in the 1800s, moved into nutrition through Wilbur Atwater, and was popularized in the early 1900s by a physician, Dr. Lulu Hunt Peters, whose diet book he says sold two million copies. In his telling she taught people to think of food as numbers, 100 calories of bread instead of a slice, and also tied weight to character, using words like sin and punishment and treating hunger as a sign of doing it right. He notes she struggled with her own weight throughout her life.

His objection is that a calorie measures energy in food but ignores digestion, hormones and individual differences. He describes hormones as "metabolic DMs", chemical messengers built from protein, about 50 of them, regulated largely by the hypothalamus. He then gives an acronym, THE DM, for what determines what calories do:

• Type of food. He describes a study comparing a whole-food sandwich (whole grain bread and cheddar) with a processed one (white bread and cheese product) of equal calories; he says the processed sandwich was followed by about a 50 percent reduction in calorie burn after the meal.
• How it is prepared. Cooking breaks down cell walls, so more calories are extractable from cooked or baby spinach than from raw, mature spinach. Neither is better; they act differently. He notes that the lab device originally used to count calories burns everything, while the body does not absorb everything.
• Energy exchange. "It costs calories to digest calories." He says protein costs about 20 to 30 percent of its calories to digest, carbohydrates 10 to 15 percent and fat roughly 0 to 5 percent, and that many Americans eat too little or poor-quality protein. He cites a study in which almonds labeled at 170 calories netted about 129.
• Digestive efficiency. Each person's stomach acid, enzymes and gut length differ and change over time. He says about 75 percent of people do not produce adequate lactase. A diet that works for a year and then stops is not a personal failure.
• Microbiome makeup. He describes studies in which gut bacteria from overweight humans made lean mice gain fat and become insulin resistant, and a study of identical twins eating the same calories in which the twin with more obesity-associated bacteria tended to gain more weight.

Diversity, the microbiome and the food system

The way to a healthier microbiome, Stevenson says, is diversity. He says higher diversity of gut bacteria is correlated with lower body weight and body fat, that people in the Western world have far fewer species than people in indigenous cultures, about a quarter as many, and that a study he cites found more variety in fruits and vegetables increases microbial diversity. Even healthy eaters fall into meal-prep ruts of chicken and rice. Probiotics will not colonize without prebiotics, the foods microbes want, and the microbes in turn make postbiotics such as short-chain fatty acids.

For this reason he declines Lewis's usual question about the five foods he would choose for life, saying it works against the urgency of eating more variety. He says most of what Americans eat comes from the same 12 foods repackaged, such as wheat, corn, soy and sugar. He blames systems as well as individuals: government subsidies, shaped by lobbyists, flow to processed-food crops, and he cites a study in which people who ate the most subsidized foods had about a 40 percent greater incidence of obesity. That, he says, is why two tacos cost 99 cents while an avocado costs several dollars.

He also gives national figures as he understands them: over 200 million Americans overweight or obese, about 12 percent metabolically healthy, over 130 million with type 2 diabetes or prediabetes, and about 60 percent with some degree of heart disease. When Lewis presses for a body fat cutoff, Stevenson admits such metrics are questionable and depend on the person. He adds that a leading gastroenterologist friend told him he received two weeks of education on food in about 15 years of training. Smart people who are taught the wrong thing, he says, "become world class in doing the wrong thing".

Leafy greens, and food that tastes good

One food group he will name is non-starchy green leafy vegetables. He cites studies linking them to greater production of satiety hormones, linking each daily serving of vegetables to a smaller waist, and a Rush University study in which older adults who ate two or more servings a day had brains about 11 years younger on average. His advice is variety (spinach, kale, bok choy) both cooked and raw.

He admits he did not eat a salad until he was 25, and says taste and culture matter: healthy food should be delicious, and manufacturers have exploited our wiring for flavor. Lewis confesses that at boarding school at 13 he had a five-gallon cafeteria milk dispenser moved into his dorm room and drank it dry weekly, and wonders what kind of athlete he might have been with better nutrition.

Stevenson's story: a new question and food first

Stevenson was a fast high school athlete whose hip broke during a 200 meter time trial at 15. At 20 he was diagnosed with degenerative disc disease and says his physician told him "I had the spine of an 80 year old man" and that it was incurable. For two years every doctor prescribed medication and bed rest. He gained weight on daily fast food, lived in pain and became afraid to stand up. He advises anyone given a life-altering diagnosis to seek a second or third opinion.

The turn came after one more appointment, when he realized he had been asking why this was happening to him and why nobody would help. He says the brain filters for whatever question it is given, and for the first time he asked, "what can I do to feel better?" He slept through the night for the first time in two years. He started on a stationary bike, briefly tried a meal-replacement shake diet and then a pile of supplements, and then, after a chiropractor friend took him to a natural foods store, asked what his discs and bones are made of and which foods supply those nutrients, such as magnesium and omega-3s alongside calcium. His rule became "food first". He says the pain was gone six weeks later and he had lost about 18 pounds. A classmate asked for help and offered to pay, which began a career that led to more than a decade in clinical practice, where he says his team, working alongside physicians, was often able to normalize clients' blood sugar largely through education.

Fasting, supplements and humility

Asked about fasting and Dr. Jason Fung's work, Stevenson says he also offers a plan for people who prefer three meals, but that simply fitting food into a 12-hour window, for example finishing at 8 p.m. and eating again at 8 a.m., is associated in the research he cites with more growth hormone, better insulin sensitivity, healthier satiety hormones and more weight loss at the same calorie intake. He says he has tried every diet framework for years at a time, and that removing foods his gut bacteria relied on left him with food sensitivities for a couple of years.

He takes far fewer supplements now. He claims supplements have gone from about 7 percent to about 20 percent of liver-damage cases. Lewis asks how anyone knows the supplements are responsible; Stevenson says it comes from patient intake and concedes there is nuance, but suggests easing off taking 20 or 30 pills a day and favoring food-based ones. He also admits how little anyone really knows, and complains that proven findings take 17 years on average to reach clinical practice. He mentions magnesium as an example of a basic that gets missed, saying it is involved in over 350 processes, helps modulate stress, and that 56 percent of Americans were deficient.

Omega-3s, oils and water

Asked for one prescription, he adds omega-3 fatty acids to leafy greens. He says humans evolved with roughly a 3 to 1 ratio of omega-6 to omega-3 and that it is now 20 or 30 to 1, promoting inflammation, and that a study found improving the ratio correlated with lower body fat. His advice is to avoid highly processed seed oils such as corn, canola and so-called vegetable oil, and to use extra virgin olive oil sold in dark glass. For DHA and EPA the densest source is cold-water fish such as wild Alaskan salmon; plant sources provide ALA, most of which he says is lost in conversion. Algae oil or krill oil are alternatives, though he notes nearly all the research is on fish and fish oil.

He calls water the most profound overlooked nutrient. He cites a study in which drinking 17 ounces produced a measurable calorie burn, and explains that every hormone and mitochondrion works in water. He claims tap water testing has found traces of pharmaceuticals, in microscopic amounts, and says "if you don't get a water filter you are the filter". He recommends filtering, notes that stripping all minerals is not ideal, and says his family drinks spring water delivered in glass. His starting guide is half your body weight in ounces, capped around 100 ounces for people over 200 pounds, adjusted for activity, though "the number one marker for you to know how much water to drink is listening to your body".

Chronic disease, COVID and the case for a healthier country

Stevenson argues that medicine excels at emergencies but keeps treating symptoms of heart disease, cancer, diabetes, Alzheimer's and obesity. He says a 2018 analysis in the Journal of the American Medical Association concluded poor diet is the leading cause of chronic disease in America. On the pandemic, he cites a CDC report that 94 percent of people who died with the virus had an average of 2.6 pre-existing conditions, and is careful to say this does not mean COVID-19 is not a factor or that those people would have died anyway. His framing is that "our chronic diseases loaded the gun and COVID pulled the trigger", and that leaders are not talking enough about getting people healthier. He acknowledges personal responsibility but, recalling a childhood on food assistance when he did not know food differed, emphasizes access and exposure.

Food, mood and relationships

The part of the work Stevenson says matters most to him is how food affects empathy. He describes an Ohio State study of couples in which low blood sugar was associated with more aggression and irritability and less willingness to see a partner's perspective. Often, he says, "people are not fighting the other person. They're fighting their biology." Being hangry is real.

He also describes a placebo-controlled study by Oxford researchers in which prison inmates given vitamins, minerals and omega-3s had about a 30 percent reduction in behavioral offenses and nearly 40 percent fewer violent offenses, a result he says was repeated with another group, with studies that changed the food itself showing even more. He explains that when the body is unwell the prefrontal cortex goes quiet and more primitive regions take over. Compassion is still possible when you are unhealthy; "It's just harder." His summary of the moment: "A nation of sick people are arguing against other sick people and wondering why nobody's listening." And his mission: "If we can get folks healthier, we can start to have healthier conversations."

Conclusion

Stevenson's argument is that food is far more than a number. Fat is a working organ with storage and burning forms, governed by hormones that respond to what, how and when we eat; calories count, but food type, preparation, the cost of digestion, individual digestion and the microbiome all change what they do. His practical suggestions are modest: eat a wider variety of whole foods, especially leafy greens, improve the balance of omega-3 fats, favor olive oil over processed seed oils, drink more and cleaner water, consider a 12-hour eating window, and lean on food before pills. His own recovery gives the advice weight, and his closing point, that better-nourished people are more patient with one another, gives it a purpose beyond appearance. The many statistics he cites are his own summaries and deserve checking, but the episode is an engaging, wide-ranging introduction to how he thinks about metabolism and health.

This is a summary of "How to Upgrade Your Brain, Boost Metabolism, Maximize Hormones & Burn Body Fat with Shawn Stevenson" from The School of Greatness, giving you the GIST so you can decide if you want the REST.