tuna is great for you, it is possibly the BEST food for anyone who is athletic. Considering that body builders need about a gram of protein per pound of body weight, tuna is perfect because it has 34 grams of protein per can, with very low fat, around 5 grams. Tuna also has omega 5 in it, which is an esential faty acid, only found in fish.
Another great thing is chicken breast (skinless), it is very low fat (99% fat free) and has around 30 grams of protein per serving.