Ulcerative colitis diet: What to eat to manage symptoms

plate of lean chicken breast on a bed of salad
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Ulcerative colitis is a type of inflammatory bowel disease (IBD) in which the immune system is thought to attack the gut lining, failing to recognise it as part of the body. A focused ulcerative colitis diet may therefore help with the management of symptoms. With the guidance of an IBD team or a dietician, those suffering from ulcerative colitis can be put on an elimination diet in order to identify potential trigger foods, or may be encouraged to keep a food diary in order to track links between certain foods and symptoms. 

Those who have undergone surgery or are struggling with an ulcerative colitis flare up may be put on a low residue diet or a low fiber diet in order to manage symptoms and lessen the burden of their disease. 

However, ulcerative colitis diets are often unique to the individual, so some experimentation under medical supervision may be necessary to find the right eating pattern for you. An ulcerative colitis diet may not work at all either, so it is important to collaborate with your medical team in order to properly manage your condition.

Ulcerative Colitis diet: What to eat in a flare up

A low residue diet is often recommended to manage symptoms of ulcerative colitis. The Canadian Society of Intestinal Research outlines ‘residue’ as the solid contents that stay in the bowel after digestion, with the goal of reducing the number of bowel movements that happen in a day. ‘Residue’ includes fiber, which is limited to 10-15g per day, but the low residue diet differs from the low fiber diet by including foods that may stimulate frequent bowel movement, such as dairy, caffeine, alcohol and gristly or fatty meat.

Dr Deborah Lee, of Dr Fox Online Pharmacy, recommends the following foods for a low residue diet:

  • Low fiber fruit and veg such as melon and bananas, as well as stewed fruit
  • Lean protein such as white meat, eggs and tofu
  • Refined grains such as white bread, white pasta and oatmeal
  • Cooked seedless and skinless vegetables such as cucumber, potato and squash.

woman chopping butternut squash on a wooden board

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While a low residue diet can be helpful in a flare-up, a spokesperson from UK-based charity Crohn’s & Colitis UK encourages speaking to a dietician before attempting to reduce your intake of fiber. “Fiber is important for your health, so it’s important to speak to a dietitian before cutting down on it,” they say. “They might suggest cutting down for a short time during a flare-up, and then slowly adding it back into your diet. It is important to stay hydrated, especially if you have lots of diarrhea. Drink plenty of fluids, but avoid caffeine and alcohol. You could take oral rehydration salts if you are losing a lot of fluid. You can buy these from pharmacies or supermarkets.”

Cooking your food may also break down some of the dietary fiber to make it more digestible, as seen in a study in the journal of Plant Foods for Human Nutrition, which indicates that the process of cooking decreases the amount of insoluble dietary fiber in some vegetables. 

Ulcerative Colitis diet: What to avoid in a flare up

A study in the journal of Advances in Nutrition found that a high fat diet can increase intestinal permeability, something that is already a problem for those with ulcerative colitis. A review in the Mediators of Inflammation journal indicates that the upset caused to the gut wall by ulcerative colitis may also increase intestinal permeability and as such, reducing foods that also impact intestinal permeability, particularly during a flare up, is advisable. 

woman suffering from lactose intolerance

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A spokesperson from Crohn’s & Colitis UK explains that there is no one-size-fits-all approach to eating while in a flare up. 

“No particular diet has been proven to help people with ulcerative colitis,” they say. “Some people find that certain foods trigger symptoms or flare-ups but others do not. Everyone is different and what works for one person may not work for another. There’s no single diet that works for everyone. While changing your diet can help you manage your symptoms, it does not replace medical treatment. It’s important not to make any changes to your diet without speaking to your IBD team or dietitian first.”

They also warn that dietary changes may not be helpful for some people with ulcerative colitis. “Avoiding certain foods helps some people manage some common symptoms,” they say. “But for some people, changing their diet has no effect. Foods that sometimes make symptoms worse include spicy or fatty foods, high-fiber foods, foods containing gluten and dairy foods. Drinks containing caffeine, sweeteners or alcohol can also make diarrhea worse.”

Ulcerative Colitis diet: Identifying trigger foods

There are a few ways that you can identify your main trigger foods:

Elimination diets

According to Dr Lee, an elimination diet may make it easier for you to identify your trigger foods. “This is only done with medical supervision,” she says. “The aim is to identify any trigger foods which could exacerbate your symptoms. Trigger foods might include high-fiber foods, foods containing lactose, certain types of sugars such as sorbitol or mannitol, sugary foods such as cakes and pastries, high-fat foods, alcohol and spicy foods.”

Keep a food diary

Another method you could use is to keep a food diary and note any correlations between your diet and your symptoms. A spokesperson for Crohn’s & Colitis UK tells Live Science: “It can be helpful when you speak to your IBD team or dietitian about your diet. It can help show whether you’re getting enough nutrients or if any foods may be contributing to your symptoms.” 

They also advise to: 

  • Make a note of everything you eat and drink, and at what time. You could use a printed food diary, a notebook, your phone or an app to do this. Include as much detail as you can.
  • Note down any symptoms you had and what time.
  • Try to keep the diary going for a few weeks and see if you notice any patterns.

Ulcerative Colitis diet: Food preparation and meal planning

While the idea of an elimination diet or restricting your intake of fiber, fat or other trigger foods may seem daunting, meal planning and preparing your food ahead of time can take some of the stress out of eating in a flare up. If your appetite is impacted as well, you can batch cook and eat what you want of a larger pre-prepared meal when you feel like eating, rather than preparing yourself a whole new meal from scratch. 

The Crohn’s and Colitis Foundation indicates that rates of depression and anxiety are higher in those with IBD, so anything that can reduce stress for those with ulcerative colitis might be helpful for managing mental health. As such, pre-planned meals based around particular dietary needs can make the day-to-day experience of ulcerative colitis slightly less stressful, and may make the experience of a flare up more bearable. 

This article is for informational purposes only and is not meant to offer medical advice.

Lou Mudge
Health Writer

Lou Mudge is a health writer based in Bath, United Kingdom for Future PLC. She holds an undergraduate degree in creative writing from Bath Spa University, and her work has appeared in Live Science, Tom's Guide, Fit & Well, Coach, T3, and Tech Radar, among others. She regularly writes about health and fitness-related topics such as air quality, gut health, diet and nutrition and the impacts these things have on our lives. 

She has worked for the University of Bath on a chemistry research project and produced a short book in collaboration with the department of education at Bath Spa University.