Can athletes be vegan?

The objection

“Plant protein is less digestible and carries less leucine, the amino acid that switches on muscle building, and vegans miss out on the creatine and carnosine that meat supplies. A 2025 meta-analysis of randomised trials found plant protein built less muscle than animal protein, and the gap was bigger in people lifting weights. In a 2026 trial, older adults who switched to a vegan diet lost muscle within 12 weeks. A handful of famous vegans proves nothing about everyone else. Serious athletes need meat.”

The answer

Athletes can train and compete on a vegan diet, and a 2025 meta-analysis of randomised trials found no significant difference in strength between plant and animal protein [1]. That is the same meta-analysis the objection cites, and its muscle results point to how to eat: soy protein showed no significant difference from milk protein, while other plant proteins, and switches to plant-based diets with the same amount of protein, gave less muscle [1]. The 2026 trial points the same way, since the older adults who went vegan ate less protein than before, and weight training roughly halved the lean mass they lost [18]. In a 2021 trial where vegans and omnivores ate the same 1.6 g of protein per kilo of body weight a day, the two groups showed no significant difference in muscle or strength gained [2].

Has a vegan won at the top level of sport?

Lewis Hamilton has: the sport’s own hall of fame profile, in its account of his 2019 season, calls him “a vegan of several years” [4], and he won the world title that year and again in 2020, for seven in all as of October 2026 [3][4]. He told the BBC in September 2017 that he had stopped eating red meat two years earlier, had now cut out fish and was aiming to go vegan [5]. A champion shows that meat is not needed to win at the top, though one career cannot show what a diet does for athletes in general, and that is the question the trials below try to answer.

Do vegans gain less strength and muscle?

On strength, a 2025 meta-analysis of randomised trials found no significant difference between plant and animal protein, while on muscle size it found a small edge for animal protein that was larger in trials with weight training [1]. The meta-analysis, from Queen’s University Belfast, pooled 30 randomised trials with 1,538 participants and found slightly less muscle mass with plant protein (standardised mean difference −0.20, 95% CI −0.37 to −0.03) [1]. Soy showed no significant difference from milk protein across 17 trials, while the other plant proteins tested, rice, chia, oat and potato, did worse when their 5 trials were pooled (−0.58, −1.06 to −0.09), and so did switches to plant-based diets in 7 trials against omnivorous diets with the same amount of protein (−0.51, −0.91 to −0.11) [1]. The gap was wider in the 10 trials that combined protein with weight training (−0.45, −0.85 to −0.05) than in the 20 without it, and it was statistically significant in the 21 trials of adults under 60 (−0.28, −0.50 to −0.06) but not in the 9 trials of people aged 60 and over (−0.05, −0.32 to 0.23) [1]. Its authors suggest that people moving towards a plant-based diet work at building muscle, for example with regular weight training [1].

The newest trial shows the cost of letting protein slip. In a 2026 Dutch trial, 72 healthy adults aged 65 and over were randomly assigned for 12 weeks to keep to their usual omnivorous diet or to switch to a vegan diet of their own choosing, with or without weight training. On the vegan diet their protein intake fell by between 19.3 and 27.7 g a day, and those who did not lift weights lost 1.15 kg of lean mass from their arms and legs while the meat-eaters held steady (+0.05 kg) [18]. Weight training roughly halved that loss, to 0.62 kg, but did not prevent it, and the volunteers were healthy older adults [18].

On strength the differences in the Belfast meta-analysis were not statistically significant, for upper-body strength across 14 trials (−0.12, 95% CI −0.51 to 0.26) or lower-body strength across 11 (−0.19, −0.44 to 0.05) [1]. The lower-body result leaned towards animal protein and reached significance in adults aged 60 and over (−0.38, −0.71 to −0.05), while in adults under 60 it showed no sign of a difference (0.01, −0.29 to 0.32) [1]. Of the 43 trials the review found, 26 gave people protein supplements and only 10 changed whole diets, and 27 had some concerns about their risk of bias [1]. The review describes none of its trials as studies of athletes, and they included older adults and people with type 2 diabetes or polycystic ovary syndrome, so they say more about plant protein in general than about trained competitors [1].

Other pooled analyses do not all agree. A 2024 Bayesian meta-analysis of 31 randomised trials in healthy people found plant protein slightly less effective for strength than other proteins such as whey, beef or milk (−0.133, 95% CI −0.235 to −0.034) [19], while a 2025 meta-analysis of eight randomised trials comparing plant-based with omnivorous diets in 188 adults found no significant difference in upper-body, lower-body or overall strength (overall 0.21, 95% CI −0.16 to 0.58) [20]. A 2024 meta-analysis of studies in physically active people who adopted plant-based diets found better aerobic performance in four studies (0.55, 95% CI 0.29 to 0.81) and no significant effect on strength and power in six, though that estimate leaned towards meat-eaters (−0.30, −0.67 to 0.07), and across both kinds of exercise performance did not change (0.01, −0.21 to 0.22) [6]. In a 2026 randomised crossover trial at four universities in the US and UK, 36 recreational runners and weight trainers spent four weeks on each diet, and neither their 12-minute run nor their machine strength differed significantly between the two, though strength came out 4.0% lower on the plant-based diet (p = 0.08) [21]. The athletes did those tests in their own time and reported the results themselves, and with so few studies behind them, none of these results is firm.

What happens when vegans and meat-eaters eat the same protein?

They gained muscle and strength with no significant difference between them in a 2021 trial that matched their protein. The trial, run at the University of São Paulo, took 19 young men who were already vegan and 19 omnivores, none of them trained, and had them lift weights twice a week for 12 weeks with protein topped up to 1.6 g per kilo a day, soy for the vegans and whey for the omnivores [2]. Both groups added 1.2 kg of leg lean mass on average, and leg-press strength rose by 97 kg in the vegans and 117 kg in the omnivores, a gap that, like every other difference measured, was not statistically significant [2]. The men chose their own diets, so the groups were not randomised, and the study was small and short.

The leucine and digestibility argument holds up best in older people. A 2026 meta-analysis of 12 studies of muscle protein synthesis, the process that builds new muscle protein, found a modest advantage for animal protein in adults aged 65 and over and similar responses in younger adults, with substantial uncertainty and with milk behind most of the animal protein data [22]. In a 2024 trial from Maastricht University, muscle protein synthesis in 16 adults aged 65 to 85 was about 47% higher in the six hours after a beef meal than after a vegan meal with the same protein and calories [23]. In younger, active people that difference did not appear: a 2025 randomised trial fed 40 physically active young adults an omnivorous or a vegan diet with 1.1 to 1.2 g of protein per kilo through nine days of weight training, and the rate at which they built muscle protein did not differ [24].

How much protein does a vegan athlete need?

Sports bodies put athletes at 1.2 to 2.0 g of protein per kilo of body weight a day, well above the UK’s reference of 0.75 g for adults [7].

Who advises it	g per kg a day	g a day at 70 kg
UK reference for adults, 1991 [7]	0.75	52.5
International Olympic Committee, athletes [7]	1.2 to 1.8	84 to 126
American College of Sports Medicine, athletes [7]	1.2 to 2.0	84 to 140
International Society of Sports Nutrition [7]	1.4 to 2.0	98 to 140
Where muscle gains levelled off, 2018 meta-analysis [8]	1.62	about 113
Suggested for vegan athletes, 2017 review [9]	1.7 to 2.0	119 to 140

The British Nutrition Foundation (2023) notes that the American College of Sports Medicine range applies to strength and endurance athletes alike, and stresses eating enough energy and carbohydrate so that protein goes to building and repairing muscle [7]. The 2018 meta-analysis, of 49 trials with 1,863 participants, found that extra protein stopped adding muscle beyond about 1.62 g per kilo a day, though that break point fell short of statistical significance and its confidence interval ran from 1.03 to 2.20, so its authors suggested about 2.2 g for anyone trying to maximise gains [8]. It concluded that the daily total mattered more than the source or timing of the protein, though only seven of its trial groups used soy or pea protein, and one of its authors has received grant support and honoraria from the US National Dairy Council, which supported some of the trials it reviewed [8].

A 2017 review of vegan diets for athletes, by David Rogerson of Sheffield Hallam University, suggested vegans aim towards the top of the range, at 1.7 to 2.0 g, because their diets contain no animal protein, while noting that some of its advice had yet to be tested by research [9]. In the São Paulo trial, with protein topped up to 1.6 g with soy, the vegans’ gains showed no statistically significant difference from the omnivores’ [2], and the Belfast meta-analysis also points towards soy [1]. Where that protein comes from on a vegan plate is covered in where vegans get their protein.

What else does a vegan athlete need to get right?

For adults, the US Academy of Nutrition and Dietetics’ 2025 position is that appropriately planned vegetarian and vegan diets “can be nutritionally adequate” [10], and for an athlete that planning starts with eating enough. Plant foods are bulky and filling, which can make a high-calorie training diet hard to reach, and the 2017 review suggests eating more often and leaning on energy-dense nuts, seeds and oils [9]. Under-eating for the training load, which the International Olympic Committee’s 2023 consensus calls low energy availability, can lead to Relative Energy Deficiency in Sport, or REDs, a syndrome that harms health and performance in female and male athletes [11]. In women, missed periods are a reason to see a doctor: the NHS lists doing too much exercise and sudden weight loss among the causes, and advises seeing a GP after three missed periods in a row [12]. If eating or training has become about restriction, help is available from Beat in the UK, Bodywhys in Ireland, ANAD in the US, NEDIC in Canada, the Butterfly Foundation in Australia and EDANZ in New Zealand.

Vitamin B12 has to come from fortified foods or a supplement: the NHS lists fortified breakfast cereals, fortified unsweetened soya drinks and fortified yeast extract or nutritional yeast flakes as vegan sources, and says a supplement may be needed [13]. The 2017 review adds iron, zinc, calcium, iodine, vitamin D and the long-chain omega-3 fats EPA and DHA to the nutrients a vegan athlete should plan for [9]. It advises monitoring iron in women with heavy periods [9], which the NHS names as a very common cause of iron deficiency anaemia, diagnosed by a GP with a blood test [14]. If a test does show iron deficiency, follow the GP’s advice on iron tablets, and keep them out of children’s reach, because an overdose of iron in a young child can be fatal [14].

Vegetarians have lower creatine stores in their muscles, and the 2017 review suggests creatine and beta-alanine supplements may be of particular use to vegan athletes [9][15]. The International Society of Sports Nutrition’s 2017 position stand, whose authors declare industry grants for creatine research and advisory roles linked to companies that sell creatine, judged creatine safe in healthy people, while noting the advice that anyone with kidney disease should consult their doctor before taking it [15], and creatine is covered in more detail in how to build muscle on a vegan diet. For under-18s, the same position stand accepts creatine only for young athletes in serious or competitive supervised training who eat a well-balanced diet, understand how to use it and keep to the recommended dose [15]. Any supplement carries a risk for an athlete who is drug-tested: the International Olympic Committee’s 2018 consensus on supplements warns that some contain substances banned under anti-doping rules, and advises a full nutritional assessment and expert professional advice before starting one [17]. The joint 2016 position of the Academy, Dietitians of Canada and the American College of Sports Medicine is that athletes should be referred to a registered dietitian for a personalised nutrition plan [16].