Avoid eating foods high in fiber such as fresh fruits and vegetables before a colonoscopy. Foods with high fiber content are not fully digested and prevent the colon from being cleansed before the procedure, according to the Memorial Sloan Kettering Cancer Center.
It is essential to eat a low-residue diet seven days before a colonoscopy, explains Memorial Sloan Kettering Cancer Center. A low-residue diet limits the consumption of high-fiber foods such as fresh fruits and vegetables. "Residue" is essentially undigested food, including fiber, that makes up stool, states WebMD. Avoiding these foods ensures the colon is clean before a colonoscopy.
While fresh fruits and vegetables should be avoided, the Memorial Sloan Kettering Cancer Center provides a list of alternatives. For example, it is fine to eat well-cooked fresh or canned vegetables without seeds such as asparagus tips, beets, green beans, carrots, mushrooms, spinach, squash without seeds and pumpkin. Other foods recommended as an alternative to fresh fruits and vegetables include cooked potatoes without skin; ripe bananas; melons; canned or cooked fruits without seeds or skin; and avocados. Besides fresh fruits and vegetables, avoid anything with seeds, whole-grain products, certain cooked vegetables like broccoli and peas, beans, lentils, peanut butter, popcorn and fruit juices with pulp or seeds before a colonoscopy. Basically, do not consume any food that is hard to digest.