Endurance
Yale, 1907: the vegetarians lasted longer. Newer research still points the same way.
+0.55Aerobic effect size, plant-based vs omnivore
In Irving Fisher’s Yale tests in 1907, vegetarians crushed the meat-eating athletes on endurance — and Fisher was not a vegetarian; he wrote that the result was “much to my surprise.” Meat-eaters held their arms out about 10 minutes on average. Flesh-abstainers lasted about five times longer. None of the meat-eaters reached 30 minutes; nearly half the plant-eaters did, nine passed an hour, and one held on past three hours. On deep knee-bends, meat-eating athletes averaged about 383; plant-eating athletes about 927. Even the sedentary vegetarians — physicians and nurses who sat most of the day — averaged about 535 and still beat the Yale athletes who ate meat. Fisher concluded the flesh-eating athletes were “very far inferior in endurance to the abstainers, even the sedentary group.” A 2024 meta-analysis still finds a moderate aerobic advantage on plant-based diets, with no loss of strength. Race times are not worse on plant-based diets. Endurance is not a reason to harm or eat animals.
What the evidence says
The main points first. Every claim is tied to a source below.
Yale, 1907: the meat-eaters lost badly
Irving Fisher published the results in the Yale Medical Journal. About 49 men took part: Yale athletes on meat, athletes who avoided flesh, and sedentary vegetarians from Battle Creek (physicians and nurses). On the arm-hold test, meat-eaters averaged about 10 minutes. Flesh-abstainers lasted about five times longer. Only two of fifteen flesh-eaters held out past 15 minutes; twenty-two of thirty-two abstainers did. None of the flesh-eaters reached half an hour; fifteen of the abstainers did — nine past an hour, four past two hours, one past three hours (200 minutes). The best meat-eater, a football guard, quit at 22 minutes. On deep knee-bends, meat athletes averaged about 383; plant athletes about 927. Even the sedentary vegetarians averaged about 535 — still above the meat-eating athletes. A lifelong meat-abstaining nurse hit 2,400. Fisher was not a vegetarian. He wrote that the result was “much to my surprise,” and concluded the flesh-eating athletes were “very far inferior in endurance to the abstainers, even the sedentary group.” The New York Times headline said Yale’s flesh-eating athletes were beaten.
Meta-analysis: aerobic performance is better on plant-based diets
Damasceno and colleagues (British Journal of Nutrition, 2024) found plant-based diets had a moderate positive effect on aerobic performance (effect size 0.55) and no effect on strength or power. That is pooled trial data. Endurance is where carbohydrate, blood flow, and lower visceral fat tend to help.
Higher VO2 max in vegans — strength held steady
Boutros found young vegan women with the same weekly training had higher estimated VO2 max than omnivores and equal muscle strength. Barnard’s 2019 endurance review found a mostly vegan vegetarian pattern reduced visceral fat and raised VO2 max even without weight loss. In a marathon, the heart is often the limiter. Plant diets tend to treat the heart well.
Race times are not slower on vegan diets
The NURMI study found no difference in best half-marathon or marathon time among vegan, vegetarian, and omnivore recreational runners. Nebl found no difference in exercise capacity and called vegan diets a suitable alternative. Stanford’s SWAP-MEAT Athlete study found performance held on whole-food plants and on plant meats. Matching omnivore performance is already enough to drop the claim that you need meat to go far. The meta-analysis is the extra upside.
Sources
Papers and datasets. Caveats stay on the card — small samples and single animals included on purpose.
Yale Medical Journal, 1907 · Small sample
The influence of flesh-eating on endurance — Yale, 1907
Irving Fisher, Yale Medical Journal, March 1907: meat-eating Yale athletes vs flesh-abstaining athletes vs sedentary vegetarians. Arm-hold and deep knee-bends. Flesh-abstainers far ahead — meat-eaters ~10 minutes arms out, plant-eaters about five times that; knee-bends ~383 vs ~927. Fisher was not a vegetarian. He called the result a surprise. Small, old, not a modern VO2 lab. The size of the gap is in the original paper.
The New York Times, March 22 1907 · Review
‘Vegetarians the Stronger’ — New York Times, 1907
Contemporary report of Fisher’s Yale tests: flesh-eating athletes beaten in severe endurance trials. The newspaper of record printed the result in 1907. The idea that meat is required for athletic strength was already contradicted then.
NutritionFacts · Review
The first studies on vegetarian athletes
Walk-through of Fisher plus the 1896 Vegetarian Cycling Club and a 1904 Belgian lifting test (plant-eaters reportedly ~80% more reps; English primary hard to locate). The Yale numbers are the ones that survive in the archives.
British Journal of Nutrition, 2024 · Meta-analysis
Meta-analysis: plant-based diets benefit aerobic performance
Damasceno et al., British Journal of Nutrition 2024: plant-based diets had a moderate positive effect on aerobic performance (effect size 0.55; 95% CI 0.29–0.81) and no effect on strength/power. That is the pooled literature, not a single study.
European Journal of Clinical Nutrition, 2020 · Observational
Vegan women: higher estimated VO2 max
Boutros et al., 2020: 56 healthy young lean women, 28 vegan / 28 omnivore, same training volume. Estimated VO2 max higher in vegans. Muscle strength not different. A vegan diet was not detrimental to endurance. The aerobic number looked better.
Nutrients, 2019 · Review
Plant-based diets for endurance sports — Barnard
Barnard et al., Nutrients 2019: plant-based patterns improve plasma lipid profile, blood flow, and glycogen from carbohydrate; a vegetarian (mostly vegan) pattern reduced visceral fat and increased VO2 max even without weight loss. Recovery and cardiovascular safety matter for people who run far.
Journal of the International Society of Sports Nutrition, 2019 · Observational
Vegan, vegetarian, and omnivore runners — Nebl
Nebl et al., JISSN 2019: ambitious recreational runners. No significant difference in exercise capacity across vegan, lacto-ovo-vegetarian, and omnivore. Authors: a vegan diet can be a suitable alternative. Matching omnivore performance already contradicts the claim that meat is required.
Nutrients, 2023 · Observational
NURMI: vegan race times are not slower
Wirnitzer et al., 2023: recreational distance runners. No significant difference in best half-marathon or marathon time by diet — omnivore, vegetarian, vegan — after training confounders. 100% plant-based nutrition is compatible with distance running. Vegan runners were not slower.
Nutrition Journal, 2022 · Clinical
SWAP-MEAT Athlete — Stanford crossover
Roberts et al., 2022: recreational athletes rotated through whole-food plant-based, plant-based meat alternatives, and animal diets. Performance held on the plant diets. Four weeks is short. Performance did not drop on the plant diets, contrary to the common claim.
Nutrients, 2021 · Review
Review: endurance has the advantage; strength is not harmed
Pohl et al., 2021: the macro mix of vegan/vegetarian diets implies potentially advantageous properties for endurance (carbs, antioxidants, endothelial function). Research has not shown a robust penalty. Craddock 2016: vegetarian diets neither improved nor hindered in the older trials. The newer meta-analysis found an aerobic advantage.