Is a vegan diet detrimental to endurance and muscle strength?

European journal of clinical nutrition. 2020;74(11):1550-1555

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Plain language summary

There is a common belief amongst the general population that a vegan diet leads to lower exercise performance due to the potential lack of dietary protein and nutrients. However, previous research that compared aerobic capacity and muscle strength between different diet groups only showed marginal variance, if any at all. But it is criticized that these studies did not always distinguish between the multiple subtypes of vegetarian or veganism. Hence this study sought to focus specifically on the comparison of strict plant-based eaters with omnivores. The participants involved were 56 active women, around their mid-twenties, with an average Body Mass Index of 22. Assessed were estimated VO2 max (an indicator of aerobic fitness), submaximal endurance performance and upper and lower body muscle strength. The 3-day food diaries of each participant was analysed and showed a similar intake of energy and fats in both groups. Vegans had higher carbohydrate, fibre, vitamin C, iron, and magnesium consumption and lower intake of protein, leucine, alanine, saturated fat, vitamin D, and vitamin B12, when compared to omnivores. Whilst upper body strength appeared to be marginally lower in the vegan group, higher levels of estimated VO2 max and significantly higher submaximal endurance levels were observed. The results contradict the common belief, demonstrating that a vegan diet appears to have no detrimental impact on endurance and muscle strength in healthy, young and lean women. In fact, the findings suggest that a vegan diet can be advantageous on endurance performance compared to omnivores. The authors propose that the higher intake of carbohydrates amongst vegans could be linked to better endurance performance and that such a plant-based diet can have favourable effects on oxidative stress and inflammatory profiles. The outcomes of this study may be of interest to those supporting the sports performance of strict plant-based eaters.


BACKGROUND/OBJECTIVES In the general population, there is a popular belief that a vegan diet may be associated with a lower exercise performance due to the lack of certain nutrients in vegan individuals. Thus, the purpose of the present study was to examine endurance and muscle strength differences between vegan and omnivore participants. SUBJECTS/METHODS We studied 56 healthy young lean physically active women (age: 25.6 ± 4.1 years; body mass index: 22 ± 1.9 kg/m2). Participants were classified as vegan (n = 28) or omnivore (n = 28) based on their eating habits. All volunteers followed either a vegan or an omnivore diet for at least 2 years. Anthropometric measurements, body composition, estimated maximal oxygen consumption (VO2 max), a submaximal endurance test (70% of VO2 max), muscle strength (leg and chest press), and dietary factors were measured. RESULTS Both groups were comparable for physical activity levels, body mass index, percent body fat, lean body mass, and muscle strength. However, vegans had a significantly higher estimated VO2 max (44.5 ± 5.2 vs. 41.6 ± 4.6 ml/kg/min; p = 0.03, respectively) and submaximal endurance time to exhaustion (12.2 ± 5.7 vs. 8.8 ± 3.0 min; p = 0.007, respectively) compared with omnivores. CONCLUSIONS The results suggest that a vegan diet does not seem to be detrimental to endurance and muscle strength in healthy young lean women. In fact, our study showed that submaximal endurance might be better in vegans compared with omnivores. Therefore, these findings contradict the popular belief of the general population.

Lifestyle medicine

Fundamental Clinical Imbalances : Structural
Patient Centred Factors : Mediators/Vegan diet
Environmental Inputs : Diet ; Nutrients ; Physical exercise
Personal Lifestyle Factors : Nutrition ; Exercise and movement
Functional Laboratory Testing : Not applicable

Methodological quality

Jadad score : Not applicable
Allocation concealment : Yes