Vegan in athletics and sport is commonly a synonym for peds to explain changes, oh yeah it's this new "vegan diet"
I'm kind of in the middle on it all mate, I'm a veggie me self but don't think that people can't be healthy/perform well eating animal products. I suppose the main prejudice though is the other way round, that you can't be as quick string etc unless you eat meat etc.
Make sure you get etiquette protein for your bodyweight to avoid muscle erosion and eat a carb heavy meal three hours before exercise make sure the meal is low fat as to not impede performance eat to suit your weight goals. (loss, maintenance, gains) End of story as long as your macros are reached it doesn't matter how you eat really when it comes to performance.