T. Colin Campbell

What Colin says, topic by topic

Vitamin B12

Campbell’s foundation site carried an article he said he wrote in 1996, arguing that B12 can be found in plants and that organically grown produce holds more of it, since roots take up vitamins made by soil microbes¹. In a note added about twelve years later (the page is dated 2008), he wrote that the clinicians Michael Greger and Alan Goldhamer had persuaded him that vegans can become deficient, and that he deferred to their advice to supplement².

In a 2013 Q&A he said blood B12 drops on an all plant diet, a finding he called consistent across many studies, and that clinicians worry about tingling or anemia when it gets too low³. In a lecture posted in 2017 he said he rarely recommends supplements but follows his clinical friends on this one, while doubting the science is settled⁴. He called it silly to argue that only animal foods supply B12, since microbes make it, in soil, in the stomachs of cattle and in the human gut⁵.

In 2021 he named B12 as the only single nutrient supplement for which he saw some evidence⁶. By 2024 he said he takes B12 because his wife asks him to, but was not convinced that everyone needs it⁷.

What all the experts say about vitamin B12

Vitamin D

At the same 2013 Q&A, asked about northern winters, Campbell said most studies measure the storage form of vitamin D, while what counts is its conversion to the active form in the kidney and other tissues⁸. He added that an acid state in the body, which diets high in animal protein can create, may slow that conversion⁹. Since clinics cannot measure all this, he said he could accept supplements when stores drop, just to be safe¹⁰.

In 2021 he said vitamin D is about sunshine and that, for himself, he saw no need to supplement¹¹. In 2024 he said vitamin D is not really a vitamin, since it forms in the skin, and called time in the sun the best source¹². He added that his own blood level, around 20 against a usual range of 30 to 60, was rated low although he spends time outdoors¹³.

What all the experts say about vitamin D

Omega-3 fats

In a 2017 interview on children’s diets, Campbell said vegan diets of around 30% fat, much of it added plant oil, carry far more omega-6, which he called pro-inflammatory, than anti-inflammatory omega-3¹⁴. With total fat down at 10 to 15% from whole foods, he said, the ratio between the two stops mattering¹⁵.

Asked in 2021 whether he still recommended algae supplements, he said he does not recommend single nutrient supplements¹⁶. In 2025, asked about a flax oil richer in omega-3 than omega-6, he said he was not fond of omega-3 taken alone as a pill, and that the ratio and total fat are what matter¹⁷.

What all the experts say about omega-3 fats

Oil

In a 2018 talk Campbell described how, from the late 1960s, Americans swapped lard and butter for plant oils such as corn oil, promoted as better for the heart¹⁸. Those oils were then hydrogenated so they would be solid enough to spread, which gave margarine¹⁹.

In a 2020 interview he said that parts taken out of plant foods and added back, such as refined sugar and added oil, are often harmful, and that the plant based community tries to avoid added oil²⁰. He drew a line between that and the oil inside whole foods such as nuts and avocado, against which he said he saw no scientific evidence²¹.

What all the experts say about oil

Protein

Campbell traces his protein research to a project in the Philippines meant to give malnourished children more protein; in a 2016 clip he said the children of families eating the most protein seemed more likely to get liver cancer²². In his rat studies, he said, raising casein, the main protein of cow’s milk, turned cancer growth on and lowering it turned growth off²³.

In a 2014 talk he put casein at about 87% of milk protein, and said soy and wheat protein did not turn on the cancer even when fed at 20% of the diet²⁴.

On human needs, he said in a lecture posted in 2011 that people need about 8 to 10% of calories as protein, while most Americans eat roughly 11 to 25%²⁵. In 2017 he said whole plant foods easily supply that much²⁶.

What all the experts say about protein

Calcium, dairy and bones

In a 2014 interview Campbell said the sulfur amino acids in animal protein become acid as they are broken down, and that the body neutralizes this acid with calcium drawn from bone²⁷. He said this predicts weaker bones and more fractures on diets high in animal protein, as reported in Western countries²⁸.

In a 2017 talk he said that, across countries, higher calcium intake goes with higher rates of bone fracture, so heavy dairy use does not mean strong bones²⁹. He noted in the same talk that he grew up on a dairy farm³⁰.

What all the experts say about calcium, dairy and bones

Calorie density

In a 2022 podcast interview Campbell said that whole plant foods bring plenty of fiber, so the stomach fills and people feel full sooner and tend to eat less³¹.

What all the experts say about calorie density

Nuts, seeds and avocado

In a 2019 webinar with John McDougall, Campbell said he disagreed with his friend Caldwell Esselstyn’s advice against nuts and seeds³². He said later research had convinced him that nuts are fine as a whole food, their fat packed by nature with antioxidants such as vitamin E³³³⁴.

In a 2020 interview he said he knew of no published evidence against eating some nuts, and described his diet advice as a goal rather than a fixed rule³⁵.

What all the experts say about nuts, seeds and avocado

Soy

Asked about soy in 2023, Campbell said the debate dates from early in his career, when soy protein emerged as a rival to the dairy industry³⁶. He called fears that soy causes breast cancer nonsense, saying its hormone-like compounds act against estrogen rather than like it³⁷.

In an article of his read on the Plant-Based Briefing podcast in 2024, he wrote that natural soy foods, unlike soy extracts and soy based supplements, consistently show a protective effect³⁸.

What all the experts say about soy

Salt

In a 2006 Q&A Campbell said taste for salt adapts: people used to salty food pick the saltiest option in taste tests, but after three or four months on less salt they come to prefer less³⁹. In a 2020 talk he named salt, along with fat and sugar, as addictive, and said the pull fades after one to three months of eating differently⁴⁰.

In 2022 he said too much salt drives up blood pressure, which is linked to stroke, and that people need only a fairly small amount⁴¹. In 2024 he described private talks with Alan Goldhamer, who uses no salt at all⁴². Campbell said he knew of no evidence that people need more than about 1,000 to 1,500 milligrams a day⁴³, but found zero salt too strict because bland food goes uneaten, and favored a little salt added at the table rather than during cooking⁴⁴.

What all the experts say about salt

Sugar

In a 2003 talk Campbell criticized a National Academy of Sciences report that let added sugars reach 25% of calories, while a World Health Organization panel had proposed a ceiling of 10%⁴⁵⁴⁶. He said the sugar industry put heavy pressure on the WHO panel to raise its figure⁴⁷.

In a 2020 interview he counted refined sugar, like added oil, among the parts of plants that are pulled out and added back to food, and said these are often harmful²⁰. In the same 2020 talk where he called salt addictive, he put sugar in the same group⁴⁰.

What all the experts say about sugar

Starches

In a 2014 interview about low-carb diets, asked whether potatoes, brown rice or whole wheat spaghetti were a problem, Campbell said they were not, since the body needs its energy from somewhere⁴⁸. He granted that people already in poor health can see bad blood results from sugars and refined starches⁴⁹, and pointed readers to John McDougall’s book The Starch Solution, saying he was not keen on the title but that both men describe the same high-carbohydrate diet⁵⁰.

What all the experts say about starches

Fasting

In a 2019 interview Campbell said that exposure to a toxic chemical he isolated in the 1960s had hurt his speech for years⁵¹. He then did a medically supervised water-only fast of 14 days and a second one of 10 days, and said his speech came back a couple of months later⁵²⁵³. He said he was convinced fasting is a good thing, while unsure whether people need fasts of 10 to 20 days⁵⁴.

In a 2025 webinar he was less certain that the chemical had caused his speech problem, and said he had returned to the fasting clinic of his friend Alan Goldhamer, whose book on fasting carries a foreword by him⁵⁵.

What all the experts say about fasting

Supplements

Campbell says he was close to the single nutrient supplement industry when it took off in the 1980s; in 2021 he said he spent three years on the stand at the Federal Trade Commission over supplement health claims⁵⁶. He said such pills may raise levels in the body in the short run but are not recommended for long term use⁵⁷.

In 2023 he gave beta-carotene as his classic case: smokers with the most beta-carotene in their blood had much less lung cancer, yet in a trial of about 29,000 smokers given beta-carotene pills, lung cancer rose⁵⁸⁵⁹. He took it as a sign that a nutrient that works within food can have the opposite effect when isolated⁵⁹.

What all the experts say about supplements

Fish and eggs

In a 2003 talk Campbell said fish protein, in his colleague Kenneth Carroll’s studies, raised blood cholesterol much like other animal proteins⁶⁰. He allowed that cold-water fish, with their omega-3 fats, might be an exception to his split between animal and plant foods⁶¹. In a 2006 Q&A he said an occasional cold-water fish is probably fine for people who stray, while pointing to mercury and to plant sources of omega-3⁶². His larger concern, he said, was that such foods keep alive the taste for fatty, salty meals⁶³.

In a 2013 Q&A he said fish rich in omega-3 may give some benefit, but fish lack the antioxidants and complex carbohydrates of plants, so the benefit is partial⁶⁴⁶⁵. People who eat some fish on top of a good whole food plant based diet, he said, probably do quite well⁶⁶.

On eggs, in a Q&A posted in 2024 he said egg protein, egg whites included, acts like casein and other animal proteins, and mentioned published evidence tying eggs to more colon cancer⁶⁷⁶⁸. In a 2026 interview he grouped eggs with milk as animal protein foods that people do not need any more than they need meat⁶⁹.

What all the experts say about fish and eggs

Fiber

In a 2011 lecture Campbell said fiber intake in rural China was about three times the American level, and that there are hundreds of kinds of dietary fiber⁷⁰. In the China data, he said, the more fiber people ate, the less colon cancer they had, as Western studies had suggested⁷¹.

In a 2014 interview he said animal foods contain no fiber while plants contain many forms of it⁷². He also warned that studying single links, such as fiber and colon cancer, in populations eating mostly animal foods gives a narrow picture that is easily misread⁷³.

What all the experts say about fiber

Fruit

At a 2013 Q&A a listener said he lived mostly on raw fruit and greens; Campbell answered that the man’s long experience spoke for itself and encouraged him to keep going, while saying he himself does not eat all raw⁷⁴. In 2023 he said fruit fills the gaps between his meals⁷⁵. In a 2025 talk he said it makes little difference which plant foods people choose, and added: “Fruits is always great”⁷⁶.

What all the experts say about fruit

Vegetables and greens

In a 2013 Q&A Campbell was asked about a 2011 Oxford review by Tim Key, a colleague he had published with, which found the evidence that fruit and vegetables cut cancer risk weak⁷⁷. Campbell said the real flaw was that almost none of the people studied ate a whole food plant based diet⁷⁸.

In 2023, asked about raw food, he called salads very good but said he saw no evidence that an all-raw diet is better, nor any data showing harm from cooking⁷⁹⁸⁰. He said salads had become a lunchtime favorite of his⁷⁵.

What all the experts say about vegetables and greens

Beans and lentils

In a 2021 talk Campbell said any mix of plant foods supplies the 9 or 10% of calories people need as protein⁸¹. Eating many legumes can push protein to 15 or 20%, which he said is no problem, because plant protein is not what causes harm⁸². Asked in the same talk about stomach trouble from legumes, he said a mild allergy to one of them may be involved and described testing by dropping one legume at a time, with a physician⁸³.

What all the experts say about beans and lentils

Whole grains, bread and flour

In a 2017 interview Campbell said refined carbohydrates such as white bread and sugar are not so good and that whole grains are the better choice⁸⁴. He added that most carbohydrate actually comes from vegetables rather than bread, and put the right share of calories from carbohydrate at around 70 to 80%⁸⁵. In 2023 he said whole grain rice or wheat is probably better than refined versions⁸⁶.

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

Potatoes

In a 2017 talk Campbell said that even a diet of potatoes alone, one of the plant foods lowest in protein, would supply enough protein, though he was not proposing a potato-only diet⁸⁷. In a 2020 talk he made the same point about tubers such as potatoes⁸⁸. In 2014 he said potatoes pose no problem on his high-carbohydrate diet⁴⁸, and in 2023 he called potatoes great⁸⁶.

What all the experts say about potatoes

Meat

In a 2018 talk Campbell traced the overemphasis on protein to its discovery in meat in 1839, which, he said, left people equating protein with meat for almost two centuries⁸⁹.

In 2019 he said his animal protein studies began in the 1960s and 1970s, before growth hormones and with few pesticides, so their results could not come from those additives⁹⁰. Grass-fed animals, he said, make exactly the same protein as feedlot animals⁹¹. In a Q&A posted in 2024 he again saw no benefit in grass-fed beef, saying the case for it rested only on its omega-3 to omega-6 ratio while the protein is the same⁹²⁹³.

Asked in 2022 about the World Health Organization classing processed and red meat as carcinogens, he said the split between fresh and processed meat came from crude analysis and offered a way to avoid talking about meat itself⁹⁴. In his view the message should have been to cut out all animal foods⁹⁵, and he saw no major difference between a lean chicken breast and a steak or hot dog⁹⁶.

What all the experts say about meat

Low-fat eating

In a 2011 lecture Campbell said fat made up only about 14% of calories in rural China, ranging from 6 to 24%, far below the 30% goal then proposed in the West⁹⁷. In a 2018 talk he read cross-country data as suggesting that total fat up to about 6 or 7% of calories carries no expected breast cancer risk, and said the same roughly holds for heart disease and colon cancer⁹⁸.

In a 2020 talk he said the body needs only about 6 or 7% of calories as fat, which whole foods such as nuts, avocados and olives readily supply⁹⁹. He added that he tells low-fat clinicians the benefit they see is less about fat than about animal protein¹⁰⁰.

What all the experts say about low-fat eating

Saturated fat

In a 2018 talk Campbell recalled how Ancel Keys, in the 1950s and 1960s, linked fat, above all the saturated fat of animal foods, and dietary cholesterol to heart disease¹⁰¹. Looking at the same kind of country data, he said plant fat showed no relationship with disease, while animal fat did, with no safe threshold¹⁰²¹⁰³.

He argued that total fat tracked animal protein with a correlation of about 94%, so the fat signal largely reflected animal food intake, a point he said was never told to the public¹⁰⁴¹⁰⁵. In a 2003 talk he went further, calling animal protein, in his view, more cholesterol-raising than saturated fat¹⁰⁶.

What all the experts say about saturated fat

Cholesterol

In a 2003 talk Campbell said the cholesterol-raising effect of animal protein was first seen in 1909 and later studied widely in people¹⁰⁷. He put the rural Chinese average at about 127 mg/dL, with their highest counties near the lowest American values¹⁰⁸.

In a 2021 talk he said a 1926 summary from the University of Michigan had already concluded that animal protein, not dietary cholesterol or fat, drove the problem¹⁰⁹. In a 2018 talk he called blood cholesterol only loosely tied to heart disease in population studies, and criticized drug research for chasing single markers like it¹¹⁰.

What all the experts say about cholesterol

Carbohydrates and low-carb diets

In a 2014 talk Campbell said low-carb diets, from Robert Atkins’s 1973 book through South Beach, paleo and the Zone, were the same idea under new names¹¹¹. With carbohydrate at 15 to 20% of calories, he said, they would be more honestly called high-protein, high-fat diets, which he called a disaster¹¹². In 2019 he called the ketogenic diet “one of the greater scams” in the history of nutrition¹¹³.

In a 2021 interview he said keto writers use the word carbohydrate loosely: carbohydrate from whole plants comes packed with fiber, protein, antioxidants and minerals¹¹⁴. He said Gary Taubes and Atkins built their case on the effects of refined sugar, not on whole plant carbohydrate¹¹⁵. The early weight loss and small drop in cholesterol on keto, he said, come mainly from eating fewer calories after leaving a diet of refined carbohydrates¹¹⁶. In 2023 he said people who stay on such high animal protein diets for six months to a year are well on the way to heart disease¹¹⁷.

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

Gluten and wheat

In a 2012 lecture Campbell said gluten sensitivity is real but that how many people it affects was unknown and that the evidence may have been hyped¹¹⁸. He suggested wheat and barley may trigger problems in combination with other foods, such as dairy, rather than being the culprit themselves, and said people who find they react to these grains should avoid them¹¹⁹.

In a 2018 interview he said gluten can be a problem for some people, perhaps 2 to 3%, not the 30 to 40% sometimes claimed, and linked the inflated claims to a popular book that cast plant lectins, including those in beans, as harmful¹²⁰.

What all the experts say about gluten and wheat

Coffee, tea and caffeine

In a 2021 interview Campbell said drinks such as coffee and tea often concentrate something from the plant and do not meet the body’s need for water¹²¹. He called coffee a diuretic¹²², said caffeine can get people hooked, and thought many people can live with coffee as long as they do not overdo it¹²³. He noted a couple of studies hinting at some benefit, but said coffee is not a recommended drink¹²⁴.

What all the experts say about coffee, tea and caffeine

Alcohol

In a 2023 interview Campbell agreed with doctors who link alcohol to cancer, while admitting he did not believe it at first and used to enjoy beer and wine¹²⁵¹²⁶. He said Walter Willett’s Harvard data had convinced him, especially for breast cancer, and that people simply do not need alcohol¹²⁷¹²⁸.

In a 2025 webinar he said he used to have a glass of wine now and then, and told how his brother drank too much wine and died of cancer¹²⁹. He called alcohol a fairly strong risk factor¹³⁰.

What all the experts say about alcohol

Organic food and pesticides

In a 2013 Q&A Campbell said he personally likes organic food, buys it when he can and grows his own¹³¹. He said the few studies comparing people who eat organic with those who do not show no big difference¹³², but on common sense and because conventional food can carry contamination he still preferred organic, while noting its cost puts it out of reach for many¹³³.

In a lecture posted in 2017 he said long studies proving organic eaters are healthier do not exist and are nearly impossible to run¹³⁴, but that the indirect evidence was good enough for him to call organic food probably a good idea¹³⁵.

What all the experts say about organic food and pesticides

Mediterranean diet

In a 2003 talk Campbell said he was involved early on, a little, with the Harvard work on the Mediterranean diet¹³⁶. He said he had concerns about crediting olive oil as the solution¹³⁷, since the people of Mediterranean countries also eat diets very high in plant foods, and their disease rates were still fairly high next to rural China¹³⁸.

In a 2013 Q&A he said studies of the Mediterranean diet share the flaw of the large European EPIC study: almost nobody in them eats a whole food plant based diet, and fat intake stays fairly high even in the lowest group¹³⁹.

What all the experts say about mediterranean diet

Weight loss

In a 2011 lecture Campbell said average body mass index was about 20 in rural China against about 27 in the United States¹⁴⁰. Yet the Chinese ate more calories per unit of body weight¹⁴¹, even office workers, the least active group, though he granted they were still more active than Americans¹⁴². Besides activity, he said low-fat plant diets turn more of their calories into body heat and tend to spur more movement¹⁴³.

In 2022 he called the slogan that people can eat more and weigh less an overstatement, since people can overeat plant foods too, mostly through added oil¹⁴⁴. On low-carb diets, he said in 2023 that people routinely lose weight at first but rarely stay on them, so the effect is short-lived¹⁴⁵.

What all the experts say about weight loss

Cravings and food addiction

In a 2020 talk Campbell said fat, salt and sugar are addictive, and that children who grow up on high-fat diets come to feel they must have them⁴⁰. In his account, that desire fades within one to three months of changing diet⁴⁰. In a 2022 interview he said fat, mostly as added oil, is the richest source of calories and so addictive that people tend to use more and more of it¹⁴⁶.

What all the experts say about cravings and food addiction

Exercise

In a 2011 lecture Campbell said extra physical activity helps keep body weight down in rural China¹⁴², and that people on low-fat plant based diets tend to move more, not only because they carry less weight¹⁴³.

In a 2023 interview he called exercise critical and said he walks every day without fail and does special exercises in the morning¹⁴⁷. He said walking helps keep in the background some trouble with balance and mild brain fog he had begun to notice¹⁴⁸.

What all the experts say about exercise

Heart disease

In a talk posted in 2018, Campbell said average blood cholesterol in the rural Chinese counties ranged from 88 to 170 mg/dL, below most American values¹⁴⁹. As cholesterol rose, he said, heart disease tended to rise, on the same line seen in Western data¹⁵⁰.

In a 2022 interview he credited Caldwell Esselstyn and Dean Ornish with showing that heart disease can be reversed, and John McDougall with similar work with patients¹⁵¹. He said they do it with a low-fat plant based diet, but that he tells them the effect owes more to removing animal protein than to cutting fat¹⁰⁰. In 2023 he said people who stay on high animal protein low-carb diets for six months to a year are well on the way to heart disease¹¹⁷.

In a 2025 talk he said the diet that turns on cancer also turns on heart disease, and that the way to reverse these diseases is to remove the foods that caused them¹⁵².

What all the experts say about heart disease

High blood pressure

In a 2022 interview Campbell said that too much salt drives up blood pressure, which is linked to stroke and heart disease⁴¹. He called salt very addictive, said some people eat so much that their blood pressure gets very high, and said people need only a fairly small amount¹⁵³.

What all the experts say about high blood pressure

Diabetes

In a 2014 interview Campbell described his view of how cow’s milk protein may help start type 1 diabetes: fragments of milk protein slip through the gut of infants, the body makes antibodies against them¹⁵⁴¹⁵⁵, and those antibodies then attack a matching sequence on the pancreas¹⁵⁶. In a 2021 talk he said type 1 diabetes is harder to reverse because of this early reaction to dairy protein¹⁵⁷.

In the same 2021 talk he said diets higher in animal protein raise blood sugar and A1c, which are tied to diabetes¹⁵⁸.

What all the experts say about diabetes

Cancer

In a 2023 interview Campbell said environmental chemicals that damage genes get most of the attention, but that nutrition is what controls whether cancer develops¹⁵⁹. He called casein, by his own reckoning rather than any official ranking, a far more potent promoter of cancer than the environmental chemicals regulators test¹⁶⁰.

In the same interview he said that, judging from the gap between countries, a whole food plant based diet could in his view prevent at least 80 to 90% of cancers¹⁶¹. Asked about existing cancer, he said it was his opinion, based on early data, that such a diet can hold cancer stable and in the laboratory reverse it, and that whether to rely on that is a personal choice¹⁶².

What all the experts say about cancer

Longevity and aging

In a 2021 interview Campbell answered Gary Taubes’s claim that no trials show people live longer on mostly plant diets by saying such long trials, with people switching diets for years, cannot be done, and that judging the question by that standard is a misunderstanding of research¹⁶³.

In 2025 he said he was 91, that heart disease ran in his family and cancer in his wife’s, and that the diet works at all ages and matters most for older people¹⁶⁴.

What all the experts say about longevity and aging

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