Seafood is another source that is usually considered to be healthier than the animal variety. Tuna, especially yellowfin tuna steaks, are ideal for anyone who enjoys seafood and grilling. A three ounce serving of yellowfin tuna contains around 25 grams of lean protein, which makes for a good dinner time or lunch option. In addition, yellowfin tuna is very filling so three ounces will fill you up without ever having the chance to overeat and gain fat to the bones. If you are a seafood lover, you can add yellowfin tuna to your diet throughout the week as you see fit to help get more protein from your diet.