Hello , i'm a waterpolo player 17 years old and my question is : can i use protein for a better fit body ? if yes what do you recommend me to use ?

Glad you asked!: Great sport! i love being in the pool or lake. Get enough protein, but no need to overdo it. More than 20 grams as a post-workout extra probably provides no benefit. Whey / soy powder is very cheap, but tofu & lean meat / fish are tastier. The real physical gains come from the exercise itself -- building muscle and trimming fat.