Effect of a Four-Week Vegan Diet on Performance, Training Efficiency and Blood Biochemical Indices in CrossFit-Trained Participants.

This interventional study examined the effect of a four-week vegan diet (Veg D ) during a four-week high-intensity functional training (HIFT) on performance, training results and blood biochemical indices in female ( n = 12) and male ( n = 8) moderate-trained CrossFit participants. The whole study group performed the maximum number of repetitions with a load of 70% one repetition-maximum (1RM) and a modified Fight Gone Bad (FGB Mod ) test before and after a dietary intervention (the group was divided to follow a Veg D or a traditional mixed diet (Mix D )) in a randomised and parallel design. Pre-exercise resting blood samples were also analysed. There was a significant improvement in the number of repetitions performed at a load corresponding to 70% of 1RM in the classic squat in the Mix D group ( p < 0.001), and in the classic deadlift in the Veg D group ( p = 0.014). Furthermore, there was a significant improvement in the results of the FGB Mod performance test after a Mix D . Moreover, an improvement in some exercises in the modified FGB Mod test (Wall Ball after the Veg D and the Mix D , and rowing after the Mix D ) was also observed. However, differences between the Mix D and the Veg D groups were not clinically relevant. In conclusion, the short-term study conducted here indicated that a Veg D in HIFT training positively affects strength endurance in the classic deadlift but is unlikely to be more beneficial in improving performance than a Mix D .