Surgery is done to remove cancer cells and nearby tissue. It is often used with radiation therapy and chemotherapy. After surgery, the body needs extra calories and protein for wound healing and recovery. This is the time when many people have some pain and fatigue. They also may be unable to eat a normal diet because of surgery-related side effects. The body's ability to use nutrients may also be changed by surgery that takes out any part of the mouth, esophagus, stomach, small intestine, colon, or rectum.