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Sugar on a plant based diet: what the doctors say
Sugar on a plant based diet: what McDougall, Esselstyn, Barnard, Goldhamer and other doctors say about added sugar, honey and fruit, with sources.
Updated . For education only, not medical advice.
Our view
Added sugar is not something a plant based diet needs: Alan Goldhamer points out that whole plant foods already supply all the carbohydrate the body uses, and T. Colin Campbell’s short definition of the diet leaves out added sugar along with salt and oil12. Sweeteners such as table sugar, honey and maple syrup bring calories without fiber, feed the mouth bacteria that cause cavities, and in some people push up blood fats, as John McDougall explained in 20223.
Yet sugar is not the main villain for most of these doctors: McDougall ranked it near the bottom of the Western diet’s problems, well behind fat, animal protein, refined foods and missing fiber4. Hana Kahleova and Neal Barnard both point to sugar paired with fat, as in cookies, cake and donuts, as the form that does the real damage56.
We give most weight to the low-fat clinicians who have treated patients for decades without selling sweet products, and their common ground is simple: keep added sugar small, get sweetness from whole fruit, and fix the core of the diet first78910. Where they part is how strict to be, from McDougall’s spoonful on oatmeal to Goldhamer’s diet with no added sugar at all710.
Where they agree
Americans eat far too much sugar, and on this the doctors and even rival diet authors agree: Christopher Gardner heard a paleo author, a Mediterranean advocate and a vegan doctor all estimate that refined grains, added sugar and packaged foods make up about 70% of the US diet1112. Dean Ornish cited food supply data showing sugar intake climbing each decade since 1950, and Goldhamer put the yearly figure at roughly 150 pounds a person1314.
They agree that whole fruit is not the problem: Caldwell Esselstyn’s FAQ allows whole fruit while ruling out juice, and Barnard in 2024 cited a study in which people who added three apples a day lost weight915. Fiber is the reason most of them give, since Ornish says it slows absorption and prevents sharp swings in blood sugar16.
Sugar combined with fat is the worst case for nearly all of them: Barnard named pie, cake and donuts6, Doug Lisle said nature almost never puts fat and sugar in one bite, while candy bars stack both with salt1718, and Kahleova traced the slower weight loss she saw with sweets to the fat in cookies and chocolate5.
Where they differ
The doctors differ on how harmful sugar is, how much is acceptable, whether natural sweeteners are any better, whether sugar is addictive, and what it does to weight419202122.
How harmful it is
Esselstyn is the strictest on the arteries: his 2014 heart study asked patients to avoid sucrose, fructose, syrups and fruit juice, and in a lecture posted that year he warned that fructose damages the inner lining of the arteries2319. McDougall, by contrast, put sugar together with salt at the low end of his list of dietary harms4. Lisle said in 2024 that he expects no serious harm from table sugar in an otherwise good diet2425, and Kahleova, asked in 2022 which food most raises diabetes risk, pointed to processed and red meat, not sugar26.
How much is acceptable
Goldhamer’s center asks patients to eat only whole plant foods, adding no salt, oil or sugar10. Jeff Novick in 2013 drew on WHO, American Heart Association and USDA advice to propose keeping added sugar under roughly 5 to 7.5% of calories27. Esselstyn told Novick in 2013 that he had never meant a total ban and gave no fixed number, only that people should cut back with good sense8. McDougall accepts a little sugar sprinkled on top of food, such as brown sugar on oatmeal, so people enjoy their meals7, and Lisle said in 2026 that this kind of small addition is not where the real problems lie28.
Honey, maple and dates
McDougall and Esselstyn put honey, maple syrup and molasses with table sugar rather than treating them as health foods319, and Novick lists every concentrated sweetener, natural or organic, on the list of foods to skip or keep very small when losing weight29. Lisle is milder: in 2024 he noted that equatorial foragers draw about 10 to 20% of calories from honey and called honey healthier than table sugar3024. Goldhamer rejects date sugar, which he sees as a processed concentrate of many dates20, while Rip Esselstyn’s PLANTSTRONG brand sells foods that leave out refined sugar and sweeten with whole dates3132. Peter Rogers in 2025 called table sugar much better than high fructose corn syrup and said some authors overstate how much fructose the liver turns into fat3334.
Addiction and abstinence
Barnard said in 2020 that sugar addiction is real, through opiates and then dopamine released in the brain, though weaker than the pull of drugs21. Goldhamer frames added sugar, with salt and oil, as a concentrated stimulus that drives dopamine and steady overeating, which he calls the pleasure trap35. Chef AJ for years treated sugar as something to abstain from, and in 2018 counted more than 2,500 days without sugar, flour, oil, alcohol and salt3637. In July 2026 she said she eats sugar again after some 25 years without it, and that easing her food rules brought neither binges nor extra weight3839. Lisle, asked in 2026 about diets with no sugar, oil or salt, said he does not treat them as a religion40.
Sugar and weight
Novick in 2008 described a study where two reduced calorie diets, one with 43% and one with 4% of calories as white sugar, produced the same weight loss, and concluded that total calories matter more than small amounts of sugar22. McDougall cited the rice diet Walter Kempner ran at Duke University, a regimen of white rice, fruit and table sugar that, in his account, reversed severe heart disease41. Jeff Nelson, describing the same diet in 2016, noted that its weight loss came on an intake that started at 400 to 800 calories daily and stayed under 1,0004243. Rogers tried the popular sugar diet in 2025, felt no stronger in the gym, had a tooth flare up, and a few months later blamed it for new weight around his middle and swings of low blood sugar44454647.
Older views
Denis Burkitt recalled that Peter Cleave blamed Western diseases on sugar, an idea Burkitt doubted because sugar is absorbed before reaching the colon, so he suspected the fiber lost in refining instead48. He still listed much less sugar among the traits of the diets in places without these diseases49. In a 2003 talk Campbell called it obscene that a US report allowed added sugar up to 25% of calories, and said the sugar industry had pressed a WHO panel to raise its 10% limit5051.
What each expert says
JMJohn McDougall
McDougall said in 2022 that simple sugars, from table sugar to honey and maple syrup, are not health food since they feed tooth decay, supply calories with little else, and may lift triglycerides3. He still ranked sugar low among the harms of the Western diet4, and accepts a little on the surface of food to make meals enjoyable7.
Esselstyn’s 2014 heart study asked patients to avoid sugary foods, syrups and fruit juice23, and in a lecture that year he warned that fructose injures the lining of the arteries19. In 2013 he explained that he wants people to cut back sensibly rather than follow an absolute ban8. His FAQ keeps whole fruit and rules out juice, because fructose without its fiber is absorbed too fast9.
In a 2003 talk Campbell attacked the US allowance of up to 25% of calories from added sugar and described industry pressure on the WHO5051. In 2020 he said refined sugar added back to food is often harmful, and his brief summary of the diet tells people to avoid added salt, oil and sugar522.
Barnard said in 2020 that sugar is mildly addictive and that sugar mixed with fat is its worst form216. In 2024 he traced diabetes to fat inside muscle cells that keeps glucose out, so cutting fat lets sugar back in53, and defended fruit with a study of three apples a day15.
On the Today show in 2012 Ornish sided with Robert Atkins on one point, that Americans overeat sugar and white flour, but chose whole plant foods over bacon and sausage as the remedy5455. In 2014 he again separated refined carbohydrates from whole grains56, and in 2019 credited the fiber in whole grains with slowing absorption16.
Goldhamer’s center asks patients to eat only whole plant foods, adding no salt, oil or sugar10, which he ties to the pleasure trap of concentrated foods35. He objects even to date sugar, as a processed concentrate of many dates20. In a 2026 review of the evidence recorded with his center’s researcher Toshia Myers, the speakers noted that no trial has yet tested removing all three from a diet that is already whole plant food57.
Rogers tried a high sugar diet in 2025 and gave it up, citing tooth pain, low blood sugar and weight around his middle4546. He argues that large amounts of fructose without fiber, in someone not exercising, push the liver toward making fat58.
Novick argued in 2008 that total calories decide weight, while modest amounts of sugar do not22. In 2013 he still argued for keeping added sugar under roughly 5 to 7.5% of calories and noted that sweetened drinks supply about half of added sugar2759.
In 2016 Nelson described Kempner’s rice diet, which included sugar and juice, as reversing kidney disease, diabetes and heart disease42. He added that its weight loss came on very few calories43.
In 2018 Chef AJ described her recovery as abstinence above all from sugar and flour36. By July 2026 she had started eating sugar again after about 25 years and said loosening her rules had calmed her digestion3839.
Kahleova noted in 2022 that the PCRM diabetes trial she discussed set only two rules, vegan and low fat, with no ban on sugar or salt60. In 2024 she linked the slower weight loss with sweets to the fat that comes with them5.
Lisle sees sugar with fat and salt as a supernormal stimulus, but said in 2020 that sugar on oatmeal does not worry him1861. In 2024 he said a little sugar added to an otherwise good diet does small harm, and in 2026 he put the real target on the main parts of a meal such as eggs and bacon2528.
We cook without added sugar most of the time and let whole fruit do the sweetening, as Esselstyn and Goldhamer advise910. We avoid sugar paired with fat, which these doctors see as the real trap, and we do not treat honey, syrups or date sugar as health foods. How strict to be is where the doctors differ, so if you have a health condition, decide that with your own doctor. This page is education, not medical advice.
Each small number links to its reference below: the video at the exact second, or the page where it was said.