A person suffering from ulcerative colitis should eat a well-balanced diet that includes protein, whole grains, complex carbohydrates, and good fats. So, you can eat fresh meat, poultry, fish, soy, plant proteins like pulses and soy, fruits, vegetables,and dairy products (if you don't have lactose intolerance). Please maintain a stress diary and to see which food items cause her more problems. Generally food items like alcohol, caffeine, and carbonated drinks, beans, cabbage and broccoli, potato, raw fruit juices and some fruits are known to be problem food items. In general, you will have to experiment and see which foods and fibers in diet cause harm and which are easily digested. Drink plenty of fluids and eat frequent small meals.
I recommend that you get a blood test for food allergies and intolerances. I have just recovered (dramatically) from IBS so serious that it hospitalized me. Treatments were only minimally helpful and I made things worse by not wanting to eat because whatever I ate resulted in pain.
So I started experimenting, looking for something in the air, or water, or foods that could be poisoning me (I thought of it as a poisoning). I found two. One minor cause was the reaction of trace minerals I was adding to water I stored in plastic bottles. But the real breakthrough came when I cut out wheat. Within a week my digestion was close to normal. Not there yet, so my doctor is having this test done for me. I know IBS is not Crohn's, but it is the same family of ailments and just as "incurable."
I forgot to mention that the wheat was a food intolerance, not an allergy.
I recommend that you go to the Crohn's and Colitis Foundation of America website, I went to a conference they have this past weekend and they have some slides on their website about nutrition and things you should eat, they recommended a low fiber diet when you're in the middle of a flare and avoiding carbonated beverages and corn, nuts. it tends to call m it tends to call my symptoms, also I find that sugar upsets my system