As a Crohn's patient the web is my friend although everyone is different so don't be surprised if something you read doesn't work for you. As it says below I've known folks who really watch their sugar intake during a flair. In the US all packaged foods have a Recommended Daily Allowance label that shows the sugar content. Sometimes it will differentiate between natural sugars and processed sugars but not always. I just skip veggies altogether but that's because they're sometimes hard to digest for me. Hope this helps.
1. Applesauce: Given the significant irritation to your gastrointestinal system during a flare, soft, easily digestible applesauce can be a good choice. Be sure to stick to an unsweetened variety, however, because added sugar can cause more inflammation. You can also make your own sugar-free applesauce by cooking peeled and sliced apples with some water and then pureeing the mixture.
2. Ripe bananas and canned fruits: Although dietitians generally recommend that people avoid raw fruits during a flare, very ripe and soft bananas are often well tolerated. Bananas are also a good source of carbohydrates, which, along with protein and fats, provide energy. Soft fruits like canned pears or peaches may also be non-irritating, says Shannon Szeles, RDN, a clinical wellness dietitian-nutritionist at Beaumont Hospital in Royal Oak, Michigan.
3. Cooked vegetables: Soft, cooked veggies such as carrots and spinach can provide important nutrients like vitamins A and K. Just make sure the vegetables are cooked through — until they’re mashable with a fork, Szeles says — so that any potentially irritating fiber is broken down.
4. Yogurt: If you’re not lactose intolerant, you can get some protein from yogurt, which is also a source of probiotics — live bacteria that may help the digestive system. Be sure to buy yogurt with live and active cultures in it, Szeles says, which is specified on the label. Avoid yogurt that contains large fruit chunks, which could be hard to digest. "It’s fine,” Szeles adds, “if yogurt has fruit that’s soft, seedless, and blended in."
5. Salmon: People with ulcerative colitis who are lactose intolerant, or who simply want to get more protein in their diet, can add salmon to the foods they eat during a flare. In addition to being a great source of protein, salmon has healthy omega-3 fatty acids that may help reduce inflammation.
Neilanjan Nandi, MD, a gastroenterologist and an assistant professor at Drexel University College of Medicine in Philadelphia, recommends baking, broiling, or sautéing salmon and cautions that "frying fish causes it to lose a lot of its nutritional value."
6. Peanut butter: Peanut butter is another lactose-free source of protein and healthy fats. Choose creamy peanut butter instead of chunky to avoid difficult digestion of nut pieces and further irritation during an ulcerative colitis flare. Try eating peanut butter with bread, advises Dr. Nandi, or wrap it in a tortilla with some turkey.
7. White rice with turmeric: If you can't tolerate most foods during an ulcerative colitis flare, you may want to stick with bland choices such as cooked white rice. If you find that the rice lacks flavor on its own, try sprinkling it with turmeric — the yellow spice whose key ingredient, curcumin, has shown some benefit in the treatment of ulcerative colitis. Turmeric is widely used in India, where the incidence of inflammatory bowel disease is lower than in the United States or Europe, says Arun Swaminath, MD, director of the Inflammatory Bowel Disease Program at Lenox Hill Hospital in New York City.
In a small study published in August 2015 in the journal Clinical Gastroenterology and Hepatology, researchers found that a curcumin supplement taken with their medication was helpful in inducing remission in people with ulcerative colitis. More research is needed, however, to examine the effectiveness of curcumin.
8. Water, sports drinks, and fruit juice: The diarrhea that often occurs during an ulcerative colitis flare can cause you to lose a lot of fluids, so replenishing them is important. "When you’re dehydrated, every symptom you have is amplified," Nandi says. Sports drinks combined with water in a 1:1 ratio can help replace lost carbohydrates and electrolytes, he says. No-pulp fruit juice is also an option, Szeles says, but avoid prune juice because of its high fiber content.