Ulcerative colitis is an inflammatory disease of the large intestine and rectum. It causes symptoms such as bleeding in the rectum, pain in the abdomen, loss of appetite, weight loss, fatigue, and anemia. An overactive immune system, stress, and genetics are the leading causes of ulcerative colitis. Food does not directly cause ulcerative colitis, but what you eat can help manage its symptoms. Some foods can relieve the symptoms, whereas some could worsen them. To help you, here are ten foods to avoid with ulcerative colitis. Dairy Products People with lactose intolerance cannot digest lactose and the sugar found in milk. Though lactose intolerance does not directly affect the large intestine or colon, it can amplify pain and diarrhea symptoms. Therefore, people with ulcerative colitis should avoid milk and any dairy products. Whole grains Whole grains are recommended as part of a recovery diet for most diseases as they contain high amounts of fiber and minerals. However, whole grains take a longer time to digest, making them one of the foods to avoid with ulcerative colitis. Fatty food When fat is digested, one of its components, linoleic acid, breaks down and is attached to the membranes of the cells within the colon.