Preparing for a colonoscopy includes modifying diet and taking a prescription bowel treatment to empty all solid food particles from the large intestine. The purpose of this is to allow the surgeon to see any polyps or other problems in the bowel, as stated by Harvard Medical School.
Cutting down on fiber for several days before the colonoscopy speeds up the digestive process. The body does not digest fiber, so eating high-fiber foods actually slows the process of digestion. This is normally a good thing because a slower digestive process leads to more even blood sugar levels. Before a colonoscopy, though, swifter digestion is better, as the goal is to get everything solid out of the colon, according to Harvard Medical School.
The day before the procedure, a colonoscopy patient only takes in clear liquids, such as clear soft drinks, sport drinks, juices, broths or bouillons. Jell-O and Popsicles are permitted because they are basically a solid form of clear liquid. Other than that, the only other substance to ingest is the bowel treatment, an extremely strong laxative that purges everything from the colon. Two hours before the colonoscopy, one should stop eating and drinking altogether, leaving the surgeon with a clear field of vision throughout the entire bowel, notes Harvard Medical School.