What are some foods that contain the most protein to help build muscle?

Depends: If you eat dairy products you can try greek yogurt or cottage cheese (otherwise soy/almond/coconut yogurt). Non dairy sources include chia seeds, beans, lentils, quinoa, eggs, artichokes, broccoli, avocado, asparagus, tofu, peas, spinach, beet greens, peanuts, pistachios, sesame seeds, garbanzo beans.

Lean proteins.: Focus on fish, pork, turkey, egg whites and protein - the real thing, not cold cuts or canned meats. And grill or bake or broil - no frying. If you don't eat meat, beans and soy are great but you need to learn how to combine them to make complete proteins for proper absorption. One gram per pound of body weight to build muscle with weight training.