There's no rule for which foods can be a problem. How you feel after eating them is the best guide. You may need to stay away from high-fiber foods and foods that are hard to digest. These can include fresh fruits and vegetables. High-fat foods, such as whole-milk dairy products and red meat, can also make your symptoms worse in a flare-up. Write down what you eat and how it affects you. If a certain kind of food often gives you trouble, stay away from it. Also note the foods that work well for you. Your doctor may have you see a dietitian or nutritionist to come up with the best food choices for you. They can help choose foods that are safe while getting correct nourishment.