The fiber in food provides the roughage or bulk that stimulates the bowel. It is generally recommended that you consume at least 25 grams of dietary fiber a day to promote good bowel health. The major sources of dietary fiber are fruits, vegetables, whole grains and dried beans.
However, a common side effect of radiation treatment and many chemotherapies is diarrhea. If you experience treatment-related diarrhea you should follow a low fiber diet and limit your intake of dietary fiber to about 10 grams a day. A low fiber diet is better tolerated with diarrhea because it will not stimulate the bowel as much and it will be easier to digest.
Low Fiber Diet for Diarrhea