Foods such as steak, fish, lean chicken, whey protein. Make sure to eat carbs with them, steak may not assist muscle building but it can help protein intake.
Explanation:
Lean Chicken and Lean fish/meats are mostly protein, the leaner they are the more protein. Chicken is the best for gaining muscle, combining with carbs is good, such as brown rice, this is from experience.
Are the bumps kinda hard and squishy? If so they could possibly be either fat deposits or tumors. Its always best to get an expert approval so I recommend taking the dog to the vet just to be on the safe side.
