What are you allowed to eat before a colonoscopy?

The day before a colonoscopy, the patient is allowed no food and only clear liquids. This includes broth, water, soft drinks, gelatin, clear juices, and coffee and tea with no milk or cream, according to the Mayo Clinic. The diet varies according to the patient's needs and the doctor's recommendations.

It is important to avoid all foods and beverages that are red, blue and purple because they may be confused with blood during the procedure. Doctors also sometimes ask patients to avoid any foods with husks or skins, such as nuts or seeds, and any foods containing insoluble fiber. The purpose of following a special diet is to clear the colon of all material so that the colon is clearly seen during the procedure, according the Harvard Medical School.