Across tens of thousands of people, the pattern is consistent: the more plant-based the diet, the lower the average body weight. It is one of the better-supported claims in the whole field.
Vegan Brief·Evidence last reviewed July 16, 2026
This is a summary of the cited evidence, not medical advice.
Vegan average BMI23.6 (lowest group)
Meat-eater average28.8
In trialsVegan diet aids weight loss
01
The BMI ladder
The clearest picture comes from the Adventist Health Study 2, which measured more than 60,000 people eating everything from fully vegan to fully omnivorous. Average body weight tracked the diet in a near-perfect staircase.
Primary source 01 / 02
Mean BMI was lowest in vegans (23.6 kg/m(2)) and incrementally higher in lacto-ovo vegetarians (25.7 kg/m(2)), pesco-vegetarians (26.3 kg/m(2)), semi-vegetarians (27.3 kg/m(2)), and nonvegetarians (28.8 kg/m(2)).
That is an observational finding, so it cannot prove the diet caused the difference on its own. But it is not the only evidence.
02
What happens when you intervene
Controlled trials that assign people to a vegan diet see weight come off. In a 74-week randomised trial in people with type 2 diabetes, the low-fat vegan group lost weight over the study.
Primary source 02 / 02
Weight loss was significant within each diet group but not significantly different between groups (−4.4 kg in the vegan group and −3.0 kg in the conventional diet group, P = 0.25)
The vegan and control diets did not differ significantly from each other here, so the honest reading is that a well-built vegan diet is an effective weight approach, not a magic one. What plant-based eating reliably does is lower the average, which is why vegans sit at the bottom of the BMI ladder across whole populations.
Plant-based diets and type 2 diabetesVegetarians and vegans get type 2 diabetes far less often, and a vegan diet helps manage it, though the trial effect on blood sugar is real and modest, not a cure.
Plant-based diets and heart diseaseThe heart-disease evidence is genuinely good for plant-based eating, and honest reporting includes the one finding that cut the other way: stroke.
Plant-based diets and blood pressurePlant-based eating lowers blood pressure by a few millimetres of mercury, small for one person but the kind of shift that moves population risk.
Frequently asked
Do vegans weigh less than meat eaters?
On average, yes. In the Adventist Health Study 2, vegans had the lowest mean BMI at 23.6, rising through vegetarians and pescatarians to 28.8 in non-vegetarians. It is an average, not a guarantee for any one person.
Is a vegan diet good for weight loss?
The evidence supports it. Observational data link plant-based eating to lower body weight, and trials of low-fat vegan diets show weight loss. As with any approach, total calories still matter.
The primary sources
The documents this page quotes. Read them yourself.
