Diet does not need to be altered five days before a colonoscopy. A patient should stop eating foods that contain seeds, such as nuts or popcorn, beans, and vegetables with skins or seeds three to four days before a colonoscopy, according to Colon Cancer Alliance. High-fat and high-fiber foods should also be avoided during this period.
The actual colon prep starts one to two days before the procedure, depending on the kind of prep the doctor recommends, states WebMD. When beginning the prep, the patient needs to cut out all solid foods and start a clear liquid diet. It may help to have a hearty breakfast and light supper the day before a prep, since less matter in the bowels means there is less to be expelled, suggests Colon Cancer Alliance.
Acceptable foods to include in a clear liquid diet are water, broth, black coffee, plain Jell-O and sports drinks, according to Everyday Health. Fruit juices are also acceptable, as long as they contain no pulp. Avoid any foods that are colored red, blue or purple. The instructions on bowel prep medications usually recommend that a patient drinks a large amount of water as well.
A colonoscopy looks at the intestines and is a routine medical procedure to look for cancer in adults over 50, explains WebMD.