A low-fiber diet is recommended before a colonoscopy so there is nothing to obstruct the view of any lesions or polyps that might be in the colon, notes Harvard Health Publications. The special diet is also recommended so that the procedure doesn't take longer than necessary.
A low-fiber diet consists of ground meat, tofu, eggs, cheese, custard, pretzels, cereals that don't have whole grains and white rice, says the American Cancer Society. Individuals should avoid processed meats, peas, beans, bran, dried fruit and seeds prior to a colonoscopy.
A low-fiber diet should begin a few days before the colonoscopy, notes Harvard Health Publications. The day preceding and the day of the procedure the individual should only consume liquids, such as black coffee, broth, clear juice, bouillon and sports drinks. The individual shouldn't eat or drink anything two hours before the colonoscopy.
A doctor can prescribe a bowel-clearing liquid to consume the evening or afternoon before the procedure, says Harvard Health Publications. If a split dose is recommended, the individual takes half of the liquid the night before the procedure and the rest six hours before the procedure. Examples of some of the liquids that may be given before a colonoscopy include polyethylene glycol, oral sodium phosphate tablets, oral sodium phosphate and magnesium citrate.