diets allow tofu. Dairy Some diets limit dairy to 2 cups per day. One diet allows of hard cheese. Several diets allow pudding or custard, sherbet, whipped cream, or ice cream. A couple of diets suggest specific lactose-free products for the lactose intolerant, such as soy milk or whipped cream. One diet prohibits whole milk, half and half, cream, sour cream, and regular ice cream. Condiments and spreads Some diets allow mayonnaise, ketchup, sour cream, cream cheese, smooth sauces and salad dressings, plain gravies, or whipped cream. Several diets allow jelly, honey, and syrup. Many prohibit jam, marmalade, and preserves. Several diets prohibit highly spiced food, but some allow spices, cooked herbs, and seasonings. Beverages Several diets specifically prohibit caffeine (two of these allow decaffeinated coffee, tea, and other drinks), but some allow coffee, tea, and carbonated drinks. Nutritional quality If the diet must be strict and followed over a long period of time, the intake of fruits and vegetables may not provide adequate amounts of vitamin C and folic acid. The quantity of calcium may also be inadequate if dairy products are restricted. In these cases, a multivitamin supplement or liquid nutritional supplement may be needed. Conditions that may require a low-residue diet A low-fiber diet may be used to prepare for or recover from various medical procedures: Abdominal surgery Colonoscopy Internal hemorrhoid surgery A low-fiber diet may also be used during acute stages of the following conditions, to rest the bowels: Bowel inflammation Crohn's disease Diverticulitis Ulcerative colitis Radiation therapy to the pelvis and lower bowel Chemotherapy Gastroparesis Uses Colonoscopy The most common preparation for a colonoscopy is a clear liquid diet accompanied by laxatives. However, this may not be the most effective preparation. A 2015 guideline issued by The Standards of Practice Committee of the American Society for Gastrointestinal Endoscopy recommends using a low-residue diet instead, also accompanied by laxatives, because of evidence that it performs at least as well for bowel cleansing and is associated with better patient satisfaction. Crohn's Disease Various guides to low-fiber diets suggest their use for short-term management of Crohn's disease, but there is little research to support this. A 2016 review of the research found that a semi-elemental whey hydrolyzed protein (WHP) diet is superior for treatment of Crohn's disease. Diverticulitis While a low-fiber diet is generally used for acute diverticulitis, the NIH guidelines recommend a high-fiber diet for patients with