Nutrition plays a key role when you’re fighting cancer — and knowing what to eat is important. When you’re being treated for cancer, you may face a variety of unwelcome side effects — everything from nausea to a sore mouth to diarrhea. But you’re not powerless over these side effects, some foods can combat them! You may not have the energy to run a marathon, but some physical activity fights fatigue, stress, anxiety, and depression, and generally improves your quality of life.