The day before a colonoscopy, you will usually be instructed to follow a low-residue or low-fiber diet, and in many cases switch to clear liquids only later that day. Studies show that a low-residue diet can clean the bowel just as well as a clear liquid diet and is often easier to tolerate.
A low-residue diet typically includes refined grains like white bread, white rice, and plain pasta, along with eggs, tender meats, and limited dairy. You should avoid whole grains, nuts, seeds, raw fruits and vegetables, and foods with skins or pulp. If you are told to follow a clear liquid diet, options usually include water, clear broth, plain gelatin, clear juices without pulp, and tea or coffee without milk. Read more about the colonoscopy prep diet your doctor may suggest.
Some preparation plans start with low-fiber foods earlier in the day and switch to clear liquids afterward. You may also be told to avoid red, blue, or purple liquids because they can affect the exam results.
Always follow the specific written instructions provided by your endoscopy center or gastroenterologist, as recommendations may vary based on your medical history and the type of bowel preparation prescribed.