First off, for those of you who are new to bodybuilding or do not know much about nutrition might not realize how much protein is in tuna fish and how much it can benefit you. Cans of tuna vary in their nutritional value, but you can find cans that contain up to about 30 grams protein, only 1 g carbs, and 0 fats per 100g. Look for tuna in brine or spring water, but stay away from tuna in oil because that is full of fat. Also tuna is an inexpensive food.