Fruits, veggies, lean proteins, and whole-grain foods give you more strength than junk food can. They can also help you manage treatment side effects, keep your weight up, and lower your risk of infection. A steady dose of good food may even speed up your recovery time. Do your immune system a favor though, and be careful with raw foods. Always wash fruits and veggies, skip the alfalfa sprouts, and stick with pasteurized products.