[Drink more whole milk to gain weight] If it is really difficult for you to gain weight but you are eager to gain weight, then drink more whole milk. 16 ounces of whole milk provides 16 grams of protein and 16 grams of fat. The fats in milk are generally short-chain, which can prevent muscle breakdown, and they are less likely to be stored as body fat than other fats, making them the best food for growing muscles. The fat in milk also helps the body absorb vitamin D, reducing the risk of cancer.