I have been vegan for almost a year now and practicing karate for a bit over a year, and I suffered a mayor improvement in my performance and fitness a couple months after turning to a vegan lifestyle. I swear by it when it comes to being healthy and training. One of the guys in my class is vegetarian and he told me giving up meat and milk was the best he could have done regarding his fitness. You just have to eat enough and clean, that's all, really.