A low-residue diet is a diet intended to reduce certain constituents of the bowel, often with consequence for functional behaviour of the bowel. It may be prescribed for patients with ailments or functional gastrointestinal disorders mitigated by fewer and smaller bowel movements each day. The diet may be used as part of the bowel preparation before a diagnostic procedure such as colonoscopy or as a short-term therapy for acute stages of gastrointestinal illnesses such as Crohn's disease, diverticulitis, bowel obstruction, and ulcerative colitis. In addition, a low-residue diet is often prescribed before and/or after abdominal surgery or cancer treatments. A low-fiber diet is a low-residue diet eliminating dietary fiber in particular. The terms are not always distinguished, but when they are, a low-residue diet will include additional restrictions on foods such as dairy products, which do not contain fiber but do develop residue after digestion. If the problem lies with fermentable carbohydrates instead, the patient may be directed to a low-FODMAP diet. Some monotrophic diets, such as the carnivore diet, are implicitly low-residue, but may also sacrifice nutrition. Almost all low-residue diets make the following recommendations: A low-fiber diet is not a no-fiber diet. A 2015 review article recommends less than 10 grams of fiber per day. Other sources recommend that a patient on a low-fiber diet eat no more than 10–15 grams of fiber per day. Some sources recommend serving sizes that contain no more than 2 grams per serving. Some diets recommend limiting servings of baked goods to 2 grams per serving. Other diets recommend limiting these servings to just 1 gram per serving. Most diets also recommend eating warm cereals such as cream of wheat, cream of rice, grits, and farina. Some diets allow additional raw fruits such as very soft apricot, canned fruit cocktail, grapes, peaches, papayas, plums, or citrus fruits without membrane, but two rule out all raw fruits. Some allow applesauce, other fruit sauces, or peeled and well-cooked apples.
Eva Sabrina Gollwitzer, Nicola Harris, Benjamin John Marsland