BackgroundIn search of the right nutrition for the athlete, numerous nutritional strategies and diets were discussed over time. However, the influence of plant-based diets, especially veganism, on exercise capacity has not been clarified.MethodsWe conducted a cross-sectional study to compare the exercise capacity of vegan (VEG, n=24), lacto-ovo-vegetarian (LOV, n=26) and omnivorous (OMN, n=26) recreational runners. To determine maximal exercise capacity, participants performed an incremental exercise test on a bicycle ergometer until voluntary exhaustion. During the test capillary blood samples were taken at several time points for the measurement of arterial lactate [lac] and glucose [glc] concentrations. To determine nutrient intake, a 24h dietary recall was conducted.ResultsThe groups showed comparable training habits in terms of training frequency (mean 3.080.90 time/wk., p=0.735), time (mean 2.931.34h/wk., p=0.079) and running distance (mean 29.5 +/- 14.3km/wk., p=0.054). Moreover, similar maximum power output (P-maxBW) was observed in all three groups (OMN: 4.15 +/- 0.48W/kg, LOV: 4.20 +/- 0.47W/kg, VEG: 4.16 +/- 0.55W/kg; p=0.917) and no differences regarding [lac] throughout the exercise test and maximum lactate could be observed between the groups (OMN: 11.3 +/- 2.19mmol/l, LOV: 11.0 +/- 2.59mmol/l, VEG: 11.9 +/- 1.98mmol/l; p=0.648).Conclusion p id=Par4 The data indicate that each examined diet has neither advantages nor disadvantages with regard to exercise capacity. These results suggest that a vegan diet can be a suitable alternative for ambitious recreational runners.Trial registration p id=Par5 German Clinical Trials Register (DRKS00012377). Registered on 28 April 2017