John McDougall

What John says, topic by topic

Vitamina B12

In a November 2007 newsletter McDougall called B12 the only criticism of his diet with any merit, while putting the chance of disease from B12 deficiency on a sensible vegan diet at under one in a million¹. His standing advice, printed at the front of his books, was at least 5 micrograms a day for anyone on his diet for more than three years, or who is pregnant or nursing². He noted that 0.3 to 0.65 micrograms a day has cured the anemia, and chose 5 micrograms as a safety margin³.

In a 2011 video he said only bacteria make B12; animal foods hold it because animals store what bacteria made, and the body conserves it so well that running out takes 20 to 30 years without good sources⁴. He still advised a supplement on any diet without obvious B12 sources⁵. In 2024 he added that people took in far more B12-making bacteria before modern hygiene⁶.

By 2022 he still recommended 5 micrograms a day, against a need he put at about 0.5 micrograms at most, while shop supplements usually carry 500 to 5,000 micrograms⁷. Because two papers he had read disagreed on the best form, he suggested taking methyl, hydroxy and cyano forms together or in turn, and said he takes his own every few months, when he remembers⁸.

What all the experts say about vitamin B12

Vitamin D

McDougall does not recommend vitamin D pills. In a December 2015 webinar he said plants make 11 of the 13 vitamins, and that of the other two he advises taking B12 but not D⁹. In 2024 he described vitamin D as a hormone the skin makes in sunlight rather than a true vitamin¹⁰.

In the 2015 webinar he argued that diseases more common far from the equator follow the richer diets eaten there more than a lack of vitamin D¹¹, and that low blood levels often reflect inflammation or obesity¹². He cited a meta-analysis of 46 randomized trials with about a quarter million people that found no benefit from supplements¹³, and two large trials of high doses in older people living at home that found more falls and fractures¹⁴.

He holds that sunlight is enough even at high latitudes. As a guide he gave five minutes of noon sun on the face, arms and hands two to three times a week for a light-skinned person at the latitude of Boston in summer and fall, and three to ten times as much for darker skin¹⁵.

What all the experts say about vitamin D

Omega-3 fats

McDougall calls the idea that people must eat fish for omega-3 fats a myth, ranked after the protein and calcium myths¹⁶. In a 2022 video he explained that only plants can make omega-3 fats, and that fish carry them because they eat algae and seaweed¹⁷. In 2024 he said omega-3 deficiency cannot develop on a whole plant food, starch-based diet, and that people should not take these supplements¹⁸.

He treats concentrated omega-3 as a drug rather than a food. In the 2022 video he said it thins the blood and suppresses the immune system, which may lower clot risk and ease arthritis but raises the risk of bleeding and weakens defense against infection and cancer¹⁹. In a 2007 newsletter he cited a review of 48 randomized trials with nearly 37,000 people that found no clear effect of omega-3 fats on deaths, heart events or cancer²⁰.

On seeds, he said in 2023 that flax, chia and hemp are about 80% fat, that grinding them or pressing them into oil makes weight gain more likely, and that the oil acts as a medicine more than a food²¹.

What all the experts say about omega-3 fats

Aceite

In a 2013 lecture McDougall summed up his program in two sentences: a diet based on starches with fruits and vegetables, with no animal foods and no free oils such as olive or corn oil²².

In a 2016 webinar devoted to oil he said extraction leaves the protein, carbohydrate, fiber, vitamins and minerals behind, so oil is at best a medicine and at worst a toxin, never a food²³. He stressed that oil holds 9 calories per gram, the most of any food, and is stored as body fat whether it is olive, coconut or flaxseed oil²⁴.

On disease he cited animal experiments from the 1970s in which vegetable oil promoted tumors more strongly than animal fat²⁵, and David Blankenhorn’s angiogram studies in which artery disease progressed as fast on vegetable oil as on a high total fat intake²⁶. His August 2007 newsletter puts the weight point in a phrase he repeats often: “the fat you eat is the fat you wear”²⁷.

What all the experts say about oil

Proteínas

In a 2021 lecture series McDougall called the belief that people suffer from protein deficiency “a deadly lie”²⁸. He bases this on William Rose’s amino acid experiments: Rose doubled the highest need found among his subjects to set a recommended intake, and McDougall said every starch and vegetable supplies all the essential amino acids above that level, so a protein-deficient diet of whole foods is impossible to design²⁹.

He also cites a study in which a man and a woman, both athletes, ate almost nothing but potatoes for six months and stayed in good health³⁰, and said adults need only about 5% of their calories from protein³¹.

He sees excess, not shortage, as the problem. In a 2022 video he ranked protein second only to fat among the harms of the Western diet, saying it overworks the liver and kidneys and that its acid load dissolves bone³².

What all the experts say about protein

Calcium, dairy and bones

In a 2013 lecture McDougall said a World Health Organization effort to collect cases of calcium deficiency found none³³. He contrasted the US minimum of 800 mg a day with the 400 mg set by the WHO, and blamed the gap on the dairy industry³⁴.

He holds that protein, not calcium intake, drives bone loss. Above about 16% of calories from protein, he said, more calcium leaves in the urine than comes in, even with two quarts of milk a day³⁵. He said countries that eat more calcium have more hip fractures because they also eat more animal protein, whose sulfur-containing amino acids create an acid load the bones must buffer³⁶. He named dairy, and cheese above all, as the most acid-forming foods³⁷.

What all the experts say about calcium, dairy and bones

Iodine

McDougall treats iodine as one of the minerals that can truly run short, since minerals come from the soil rather than being made by plants. In a December 2015 webinar he recalled the goiter belt around the Great Lakes a century ago and parts of rural Africa where iodine is supplemented today³⁸.

He argued that in modern countries people eat food grown in many places, so a shortfall in one soil is made up by the next food³⁹. He made the same point in a 2022 talk on supplements, naming apples from Washington, corn from Idaho and rice from Louisiana⁴⁰.

What all the experts say about iodine

Calorie density

In a 2022 lecture on why people gain weight McDougall described his diet as calorie dilute, with fewer calories in a given volume⁴¹. He ranked foods from oils at 9 calories per gram, through cheese and meat at about 4, to corn and rice at about 1 and potatoes at about 0.6⁴². He added that bulk alone does not satisfy: fiber pills fill the stomach without ending hunger, and the food must also supply sugar to the brain⁴³.

The idea runs back at least to an April 2002 newsletter, which ranked potatoes as the least calorie-dense food on its list, at one calorie per gram, against about 4 for sugar, cheese and beef and 9 for vegetable oils⁴⁴.

What all the experts say about calorie density

Nuts, seeds and avocado

In his 2016 webinar on oil McDougall said nuts, seeds, avocados and coconuts are not unhealthy, but at 80 to 90% fat they are the richest sources of energy and do not help people stay trim⁴⁵. His August 2007 newsletter likewise warns that whole foods rich in fat, like nuts, seeds, olives and avocados, can be expected to add weight⁴⁶.

For the fastest weight loss, he said in 2022, nuts, seeds, olives and avocados have to go. He called them delicacies and recalled that, as a boy, his family of six took a week to crack a five-pound bag of nuts⁴⁷.

What all the experts say about nuts, seeds and avocado

Soja

In a 2011 video McDougall said soy is not needed at all: his starch-based diet gives all the protein and nutrients without it⁴⁸. About 10% of the dishes in his books and on his website use traditional soy foods such as tofu, miso, tempeh and edamame, and he called a couple of ounces a day reasonable⁴⁹.

What he rejects is processed soy: burgers, cheeses and nuggets made from isolated soy protein, which he called fake food⁵⁰. In 2023 he warned again that such products, and soy protein powders, are very high in protein⁵¹.

Asked in 2023 about soy and breast cancer, he said doctors do not know for sure and the data are incomplete, but that the papers he has, from Japan for example, show women with breast cancer who eat more soy living longer⁵².

What all the experts say about soy

Salt

In an August 2008 newsletter McDougall called salt a scapegoat for the Western diet⁵³. He wrote that his diet with no added sodium provides under 500 mg a day, and that half a teaspoon of salt on the surface of food adds about 1,100 mg, for 1,600 mg in all⁵⁴. He granted that salt does raise blood pressure a little, more in people of African descent and in those with diabetes or kidney disease⁵⁵.

He kept the same practice in 2022: his program cooks with very little salt and puts shakers on the table, because salt on the surface reaches the tongue while salt stirred into a stew loses its taste⁵⁶. He has said that salt and sugar on the surface often decide whether people enjoy their food at all⁵⁷.

What all the experts say about salt

Sugar

In 2022 McDougall said simple sugars such as table sugar, honey, molasses and maple syrup are not health food: they feed the bacteria that rot teeth, add empty calories and can raise triglycerides in sensitive people⁵⁸. Still, he ranked sugar near the bottom of the Western diet’s harms, after fat, protein, refined foods and lack of fiber, together with salt⁵⁹.

He accepts a little sugar on the surface of food, such as brown sugar on morning oatmeal, to help people enjoy their meals⁵⁷. He also pointed to Walter Kempner’s rice diet at Duke University, which included white rice, fruit and table sugar, and which he credited with reversing severe heart disease⁶⁰.

What all the experts say about sugar

Starches

McDougall describes his program as built on starches such as corn, rice, potatoes, beans, peas and lentils, plus fruits and vegetables²². In his 2013 lecture he said all large, successful populations in recorded history got most of their calories from starch, leaving it only when they grew rich enough for meat and dairy⁶¹.

He traces his own view to 1973 to 1976, when as a sugar plantation doctor he cared for some 5,000 Filipino, Japanese, Chinese and Korean workers who lived on rice and were fit and free of the diseases he had been trained to treat⁶². In 2021 he summed it up by calling humans starch eaters, or “a starchivore”⁶³.

What all the experts say about starches

Fasting

McDougall does not fast himself. In a 2017 webinar he said he had gone three days without food twice, as an experiment, and found it too painful⁶⁴. Asked about intermittent fasting in 2023, he called his knowledge of it superficial, noted that most religions include fasting and guessed it may make people more aware of food, while setting it apart from the therapeutic water fasting of his friend Alan Goldhamer⁶⁵.

In a 2016 webinar he said he sent some patients who had not improved on his elimination diet to TrueNorth Health Center for a water fast, though in his experience few gained an added benefit from it⁶⁶.

What all the experts say about fasting

Supplements

In a May 2010 newsletter titled “Just to be on the Safe Side: Don’t Take Vitamins”, McDougall argued that a pill is not a plant: people who eat more fruits and vegetables get less cancer, yet two trials of beta-carotene pills in high-risk people found more cancers⁶⁷. He cited two 2008 Cochrane reviews that found beta-carotene, vitamin A and vitamin E supplements raised mortality⁶⁸.

In webinars from 2015 and 2022 he repeated that plants make 11 of the 13 vitamins and are the best package for them, with B12 the one vitamin he recommends taking⁹⁶⁹.

What all the experts say about supplements

Hierro

McDougall holds that iron deficiency rarely if ever comes from a poor diet. In 2022 he said it results from blood loss, often unseen, and from poor absorption, which he linked most often to dairy, whose calcium and phosphorus bind iron into forms the gut cannot take up⁷⁰. In 2017 he described a starch-based diet as loaded with iron and zinc⁷¹.

Asked in 2016 about low iron levels, he said the first step is to rule out bleeding, and named cow’s milk as the second most common cause of anemia in children⁷².

What all the experts say about iron

Fish and eggs

In a February 2003 newsletter McDougall argued that the Japanese stay healthy in spite of fish, which they eat only as a condiment to a rice-based diet⁷³. He wrote that fish has no carbohydrate, fiber or vitamin C, that per calorie it carries more cholesterol than beef, pork or chicken, and that its acidic protein promotes bone loss⁷⁴.

He also points to pollutants. In 2022 he said fish concentrate industrial chemicals from the algae they eat, and bigger fish that eat smaller ones concentrate them further⁷⁵. His June 2007 newsletter, “Confessions of a Fish Killer”, describes two decades of catching and eating large fish such as tuna and salmon⁷⁶, and in 2016 he said he had pledged some 15 years earlier never to eat anything from the sea again⁷⁷.

What all the experts say about fish and eggs

Fibra

McDougall credits the surgeon Denis Burkitt, whom he heard speak at his hospital in Grand Rapids, Michigan, for his interest in fiber. In a 2022 lecture he explained fiber as the carbohydrate in food that the gut cannot digest, small chains of sugars that pass through unabsorbed, rather than coarse bristles that scrub the intestine⁷⁸.

He counts lack of fiber among the main faults of the Western diet. In 2022 he ranked refined foods stripped of their fiber right after fat and protein among its harms, ahead of salt and sugar⁷⁹.

What all the experts say about fiber

Fruit

McDougall treats fruit as a welcome addition to a starch-based diet, not its base. In a 2014 lecture he said one to four pieces of fruit a day is fine, but that fruit’s simple sugars do not satisfy the appetite for long, and that outside modern stores fruit disappears in fall and winter⁸⁰. In 2023 he said he had never met anyone who stayed on a fruit-only diet, only people who tried it for weeks or months⁸¹.

In a 2021 talk he explained why his program limits fruit to two or three pieces a day: otherwise newcomers eat 20 or 30 at a sitting, or dried fruit, and miss the starch, while the sugar spares body fat from being burned⁸². He admitted he had not always kept that limit himself, recalling eating bushels of nectarines from a tree by his house without trouble⁸².

What all the experts say about fruit

Vegetables and greens

In a 2011 video McDougall warned against trying to live on green and yellow vegetables: they are so bulky and low in calories that a person would need bushels of broccoli a day, and those who try often end up with cramps and fatigue⁸³. He said the diet must rest on starches, with green and yellow vegetables as side dishes that add color, interest and nutrients such as vitamins A and C⁸⁴.

For faster weight loss, he said in his 2022 lecture, people can raise non-starchy vegetables such as broccoli, kale and celery from about a tenth of the diet to a quarter, and at most to half; past a 50/50 split, he said, hunger returns and control is lost⁸⁵.

What all the experts say about vegetables and greens

Beans and lentils

Asked in a 2016 webinar about beans and kidney health, McDougall said a person with normal kidneys can handle about a cup of cooked beans, peas and lentils a day, guidance he had kept for 40 years, and that he and Mary eat them⁸⁶. His caution was protein: some people love beans so much they eat them at every meal, and beans are about 30% protein against a need he puts near 5% of calories, though healthy kidneys can manage plant protein⁸⁷.

In a 2017 webinar he told people new to the diet to give their gut bacteria a couple of weeks to adjust; beans, peas and lentils will always bring some extra gas, he said, but it stops smelling so bad⁸⁸.

What all the experts say about beans and lentils

Whole grains, bread and flour

In a January 2008 newsletter McDougall called cereal grains the most important part of the human diet, with 70% to 83% of their calories as starch⁸⁹. He listed the charges against grains, that they fatten, rob nutrients, cause intolerance and addiction, and answered that obesity is unknown among the more than 3 billion people who live on grain-based diets today⁹⁰. He also cited genetic work showing that humans carry more copies of the starch-digesting amylase gene than great apes⁹¹.

In a December 2011 newsletter he described a 1979 Michigan State study in which overweight young men who added 12 slices of bread a day lost weight over eight weeks, and used it to launch an “Eat More Starch” challenge⁹². In a 2022 video he rejected the claim that grains cause inflammation, saying the research points to animal foods instead⁹³.

What all the experts say about whole grains, bread and flour

Potatoes

In a 2011 video McDougall defended the potato against school-lunch limits and a New England Journal of Medicine paper calling it fattening, noting that a large potato has about 150 calories, so ten would supply only 1,500⁹⁴. He said potatoes sustained whole civilizations, from the Andes to Ireland, where the population doubled within 40 years of their arrival⁹⁵. He cited a 1928 report of a man and a woman who lived on little but potatoes and water for six months and did well⁹⁶.

In a talk posted in 2024 he said potatoes are fattening only because of the bacon, butter, sour cream and cheese piled on them, and that what people miss on a plain potato is mostly salt and sugar⁹⁷. He called sweet potatoes perhaps slightly better than white ones, but only in theory, since root vegetables are so alike⁹⁸.

What all the experts say about potatoes

Meat

In a May 2007 newsletter McDougall wrote that as a young man he believed eating muscle was the best way to build muscle, a belief he linked to his own acne and a stroke at 18, and that he had switched to mainly plant foods 35 years earlier⁹⁹. He called meat the right food for his cats and dog but not for people, who become sick on meat-centered diets¹⁰⁰.

He argued that the protein, iron, zinc and B vitamins the beef industry advertises are almost never lacking in anyone with enough food, while meat lacks calcium, fiber and vitamin C and brings too much fat, cholesterol, protein, microbes and chemical contaminants¹⁰¹. He also wrote that people enjoy the sauce, bun and vegetables more than the meat itself, since the tongue has no taste buds for protein and fat¹⁰².

What all the experts say about meat

Low-fat eating

McDougall accepts the label “low-fat vegan” but worries about it. In a 2011 video he said a low-fat vegan could live on cola and low-fat potato chips, and that he would rather be known as a “starchivore”, someone who gets most calories from rice, corn, potatoes, beans, pasta and bread¹⁰³. In another 2011 video he said many followers who eat low-fat are still overweight because white sugar, cakes, cookies and low-fat chicken also qualify; the goal is whole starches and vegetables, not a fat number¹⁰⁴.

In his March 2016 newsletter he defined a truly low-fat diet, as taught by Pritikin, Ornish, Barnard, Esselstyn, Novick and himself, as about 10% of calories from fat, and said such a diet has never been honestly tested against the Mediterranean or low-carb diets¹⁰⁵.

What all the experts say about low-fat eating

Grasa saturada

McDougall treats “saturated fat” mostly as a stand-in for animal foods. In a 2015 webinar he said industry uses the term to confuse the public, who do not link it with the meat, poultry, cheese, dairy and eggs on their plates¹⁰⁶. He said his diet of starches plus fruits and vegetables is naturally about 7% fat, with very little of it saturated¹⁰⁷.

In a 2016 webinar on the US dietary guidelines he complained that the guidelines name healthy foods outright but describe harmful ones only by nutrients, such as saturated fat, cholesterol and protein, that people cannot see on a plate¹⁰⁸.

What all the experts say about saturated fat

Cholesterol

In a 2022 video McDougall called blood cholesterol a risk factor and a sign of the health of the arteries rather than a disease: people die of diseased arteries, not of a number¹⁰⁹. He said the rich Western diet raises cholesterol along with blood pressure and triglycerides, and that although some people with high cholesterol have clean arteries, the usual pattern is more heart attacks and strokes as cholesterol rises¹¹⁰.

He put the ideal at 150 mg/dL or below, citing the Framingham study and his own work on its data some 40 years earlier¹¹¹. He sees food as the first step and drugs as the second, warning that statins can push levels so low the body may lack raw material for vitamin D and sex hormones¹¹². He reported that among nearly 2,000 people at his program cholesterol fell by an average of 22 mg/dL in seven days¹¹³.

What all the experts say about cholesterol

Carbohydrates and low-carb diets

McDougall has argued against low-carb diets since the early 1970s, when Robert Atkins led the field. In a 2024 video he described the Atkins diet as bacon, butter and cheese, short on plants and high in fat, and said a library of research links such eating to heart disease, diabetes and cancer¹¹⁴. He recalled telling Atkins on his radio show that they agreed on one point: the diet left most followers, about 70% in Atkins’s own reports, constipated¹¹⁵.

He dismissed newer low-carb versions that add nuts, seeds, avocados and soy-based fake meats and cheeses, saying a side of carrots cannot turn a high-fat meat or dairy meal into health food¹¹⁶. In a March 2016 newsletter he wrote that a 2004 trial comparing a ketogenic diet with a “low-fat” diet was funded by the Atkins Foundation, and that the comparison diet still got 29% of its calories from fat¹¹⁷.

What all the experts say about carbohydrates and low-carb diets

Gluten and wheat

In a March 2013 newsletter McDougall called gluten-free diets harmful for the general population, the exception being the roughly one percent of people with celiac disease, for whom strict avoidance is essential¹¹⁸. He suspected that most people who blame wheat for vague symptoms are really sick from meat, dairy, vegetable oils and junk food, and that any benefit from a stricter diet comes from dropping those foods¹¹⁹.

He saw the trend, fueled by the book Wheat Belly, as low-carb eating in disguise and a diversion from a starch-based diet, noting that many civilizations relied on wheat, barley and rye¹²⁰. He added that gluten-free products often carry more fat, sugar and calories, and that he knew of no published report of weight loss on a gluten-free diet in people without celiac disease or gluten sensitivity¹²¹.

What all the experts say about gluten and wheat

Coffee, tea and caffeine

In a 2022 video McDougall admitted that coffee has long been one of his own favorite drugs: a stimulant that clears the mind in the morning but can keep people awake at night and leave heavy drinkers jittery¹²². He doubted studies that link coffee with less heart disease and cancer, suggesting they get published because people love “good news about their bad habits”¹²³.

On the harms, he said coffee drives up stomach acid, and decaf does so just as much, because the irritation comes from other alkaloids in the bean rather than from caffeine¹²⁴. He explained that boiled or percolated coffee raises cholesterol while a paper filter traps the substances responsible, and that decaf raised it even more¹²⁵. For poor sleep or high cholesterol he said the answer is to quit, or at least to use a paper filter, adding that the body recovers within two or three days of stopping¹²⁶.

What all the experts say about coffee, tea and caffeine

Alcohol

In a 2011 video McDougall said that for most drinkers, perhaps nine in ten, alcohol does no lasting damage, but that for the remaining one a doctor’s blessing could end in tragedy, such as a car crash or violence at home¹²⁷. For that reason he holds that no doctor should recommend it¹²⁸. When drinking has become a problem, he said, moderation does not work: as with tobacco, the only answer he has seen succeed is to stop completely¹²⁹.

What all the experts say about alcohol

Chocolate

In his January 2012 newsletter McDougall commented on a small trial in which dark chocolate curbed appetite more than milk chocolate¹³⁰. He wrote that cocoa butter, with all its fat and calories, is the main problem in chocolate bars, and that the chocolate desserts at his program are made with fat-free cocoa powder and sugar¹³¹. He serves them because people love them, saying his diet “is not prison food”, and placed chocolate with nuts, seeds, olives and avocados as rich plant foods that trim, healthy people can use in small amounts¹³².

Asked about that newsletter in a 2017 webinar, he said he did not remember writing it, but agreed that chocolate is a plant food with no cholesterol; the trouble, he said, is the milk and other ingredients mixed in to make candy bars and cream pies¹³³.

What all the experts say about chocolate

Juicing and smoothies

In a December 2007 newsletter McDougall wrote that exotic juices such as goji, noni and mangosteen sell for high prices with almost no research in humans behind them, while cheap juices like cranberry have better evidence¹³⁴. He argued that people in Western countries suffer from diseases of excess rather than missing nutrients, so extra nutrients in a bottle cannot fix them¹³⁵.

He cited a 1977 experiment comparing whole apples, applesauce and apple juice: the juice was drunk eleven times faster than the whole fruit, satisfied appetite less and pushed insulin higher¹³⁶. He concluded that juice has stopped being a whole plant food, and that drinking it in place of the whole food will, at the very least, promote weight gain¹³⁷.

What all the experts say about juicing and smoothies

Organic food and pesticides

In an October 2008 newsletter McDougall explained why his program does not teach people to buy organic food: moving sick patients to conventionally grown starches, vegetables and fruit brings large gains within days, and an extra rule would make the change harder¹³⁸. Even so, he said his own family tries to buy organic, and that people can and should do both¹³⁹.

He wrote that there is no conclusive evidence that organic produce is more nutritious, and that an organic label on meat, dairy or junk food does not make it healthy¹⁴⁰. In his view the bigger step against pesticides is moving from animal to plant foods, since most of the chemicals people take in come from foods high on the food chain, where they collect in fat¹⁴¹. He did list fruits and vegetables with high residues, such as apples, peaches and strawberries, as worth paying extra for organic¹⁴².

What all the experts say about organic food and pesticides

Mediterranean diet

In an April 2013 newsletter McDougall commented on the PREDIMED trial, which credited olive oil and nuts with fewer cardiovascular events. He pointed out that companies supplied the oil and nuts, that only strokes fell while heart attacks and overall deaths did not, and that the comparison “low-fat” group still ate about 37% of its calories as fat¹⁴³. He added that swapping one fat for another brings no weight loss, citing obese women in a Mediterranean country who got more than half their fat from olive oil¹⁴⁴.

In a March 2016 newsletter he wrote that the Mediterranean diet, now a global brand, was healthier in the distant past because it was rich in starches, vegetables and fruit, and was healthy despite, not because of, the olive oil and nuts marketed today as its secret¹⁴⁵. He noted that children and adults around the Mediterranean are today among the most obese in the world¹⁴⁵.

What all the experts say about mediterranean diet

Weight loss

In his 2022 lecture on why people get fat, McDougall said weight comes down to calories in against calories out, and saw three ways to rebalance them: portion control, which leaves people hungry all the time, low-carb diets, or a starch-based diet¹⁴⁶. He rejected the idea that rice and potatoes turn into body fat, saying the human body turns very little sugar into fat¹⁴⁷. His central principle is that carbohydrate, not bulk or fat, satisfies the hunger drive¹⁴⁸. In a 2022 video he added that peoples who lived on rice, corn or potatoes, from Asia to the Aztecs, Mayans and Incas, were never pictured as overweight¹⁴⁹.

In a 2014 paper he led in Nutrition Journal, 1,615 people who ate a low-fat vegan diet without limits for seven days at his live-in program lost a median of 1.4 kg¹⁵⁰.

What all the experts say about weight loss

Cravings and food addiction

In an October 2006 newsletter McDougall compared refined flours and sugars to cocaine purified from the coca leaf: carbohydrates in whole starches, vegetables and fruits are essential to life, but purifying them strengthens both their pull and their harm¹⁵¹. He wrote that the tongue tastes only carbohydrate with pleasure, that concentrated carbohydrate triggers opioid and dopamine reward in the brain, and that for some people changing diet seems harder than giving up tobacco or heroin¹⁵².

By 2023 he objected to the word addiction itself. In a talk with Chef AJ he said that, as a doctor who has seen true withdrawal from opioids, alcohol and tobacco, with seizures and ambulances, he has never seen anyone have a seizure from giving up a food¹⁵³. He called it a strong habit instead, and suggested the word addiction can make people feel excused from taking control¹⁵⁴.

What all the experts say about cravings and food addiction

Exercise

Asked in 2022 how important exercise is for heart disease, McDougall recalled the runner Jim Fixx, who claimed marathon runners never die of heart disease and then died of it at 56¹⁵⁵. He repeated Nathan Pritikin’s advice not to start a serious exercise program until after changing the diet, because the arteries are unstable¹⁵⁶. He favors moderate activity such as walking, stationary cycling or swimming, calling walking ideal, and said he windsurfs among sharks for pleasure, not health¹⁵⁷.

He said exercise speeds weight loss, but the weight returns when the exercise stops unless the food has changed, and that exercise does not lower cholesterol or prevent heart disease or cancer¹⁵⁸.

What all the experts say about exercise

Heart disease

In a 2022 lecture on heart disease McDougall argued that angioplasty, stents and bypass surgery do little for stable, chronic coronary disease. He cited the COURAGE trial of nearly 2,300 patients, in which the procedure did not reduce deaths, heart attacks or other major events¹⁵⁹. In his view the hard, scarred plaques that surgeons can see and treat rarely kill; heart attacks come from small, fresh plaques that burst like a pimple and set off a clot, which no procedure reaches and which he said only diet treats¹⁶⁰.

He holds that a low-fat, starch-based diet heals the artery wall and steadies those plaques¹⁶¹. As evidence he cited Walter Kempner’s electrocardiogram findings at Duke in the 1940s¹⁶², and Caldwell Esselstyn’s angiograms of patients on a diet close to his own; the scar does not reverse, he said, but the inflamed part does, usually enough to end chest pain¹⁶³.

What all the experts say about heart disease

High blood pressure

McDougall sees high blood pressure as a sign of a sick blood vessel system rather than a disease in itself. In a 2011 video he said pressure rises to push blood through arteries narrowed by fat and cholesterol, through sludged blood and spasm, so lowering the number with pills leaves the underlying illness unchanged¹⁶⁴. He said he follows British guidelines, starting drugs only when pressure stays near 160 over 100 for months, rather than at 140 over 90¹⁶⁵.

In a 2022 video he named food as the main lever, with exercise and sunshine also helping, and blamed fatty foods for making blood cells stick together and raising resistance¹⁶⁶. He called sodium the scapegoat of the Western diet: cutting salt to official targets lowers the top number by only two or three points, although Walter Kempner’s very low-salt rice diet produced large drops¹⁶⁷.

In his 2014 paper on 1,615 people at his live-in program, systolic pressure fell by a median of 8 mm Hg in seven days, even though most blood pressure drugs were reduced or stopped at the start¹⁶⁸.

What all the experts say about high blood pressure

Diabetes

In a 2011 video McDougall described type 2 diabetes as closely tied to excess weight¹⁶⁹. He called it an adjustment rather than a failure of the body: after storing extra fat from a rich diet, the body becomes resistant to insulin to stop further gain, and blood sugar rises even though insulin output is often about double the normal¹⁷⁰.

He said that a switch to starches such as rice, corn and potatoes, with some vegetables and a little exercise, makes insulin resistance fade and blood sugar fall, so the need for medication drops quickly¹⁷¹. He reported commonly taking patients off 60 to 120 units of insulin on the first day of the diet at his program, told viewers to see their own doctor first because things change fast, and called type 2 diabetes curable¹⁷².

What all the experts say about diabetes

Cancer

In a 2011 video McDougall said in 1982 he published the first journal study of diet as a treatment for breast cancer¹⁷³. He holds that a Western diet loaded with fat, cholesterol and chemicals causes breast, prostate and colon cancer, pointing to the low rates of these cancers among Asians eating rice and vegetables¹⁷⁴. He said the research shows that a diet change makes a difference even after diagnosis, helping people live longer and not only feel better¹⁷⁵.

In a 2017 talk he rejected the idea that sugar feeds cancer, which he tied to the low-carb movement, saying populations that eat the most starch, such as Seventh-day Adventists in Loma Linda, have less breast, colon and prostate cancer¹⁷⁶¹⁷⁷.

What all the experts say about cancer

Dementia and the brain

In a June 2004 newsletter McDougall argued that Alzheimer’s disease can be prevented and treated with steps already known: a healthful diet and avoiding aluminum¹⁷⁸. He compared the plaques in the brain with those in the arteries, noting that the tissue changes are similar and that a diet high in cholesterol and fat drives atherosclerosis¹⁷⁹.

He called aluminum a recognized nerve toxin and, in his view, the root cause of the disease, adding that an acid-forming diet heavy in meat, eggs and cheese raises aluminum in the blood and brain¹⁸⁰. He still held this view in 2023, linking the spread of the disease to the use of aluminum since World War II¹⁸¹.

What all the experts say about dementia and the brain

Longevity and aging

In a January 2006 newsletter, nearing 60, McDougall wrote that aging itself cannot be stopped or reversed, but the diseases that come with it can be prevented and useful life extended; he said he hoped to reach 100¹⁸². He pointed to Japanese people on a rice and vegetable diet, who lived four to five years longer than Americans¹⁸³, and to vegetarian Adventists, who lived about 10 years longer than other white Californians, though he felt even they ate too much dairy, eggs and oil¹⁸⁴.

He noted that eating less is the one life-extending method science accepts, but rejected semi-starvation; his diet, he wrote, cuts calories, fat and protein by its nature, by 400 to 800 calories a day, without hunger¹⁸⁵.

What all the experts say about longevity and aging

Each small number links to its reference at the bottom of the page: the video at the exact second, or the page where it was said.