Ulcerative Colitis Diet: What to Eat in Flares and Remission

There is no single ulcerative colitis diet that stops flares. The American Gastroenterological Association (AGA) advises a Mediterranean-style pattern for people with inflammatory bowel disease (IBD), and says a diet low in red and processed meat may reduce ulcerative colitis flares^[1]. During a flare, hospital dietitians suggest softer foods with less insoluble fiber and more protein^[2].

This guide covers what to eat during a flare and in remission, which foods and additives are worth limiting, the evidence behind popular diets, and the nutrients to watch. Diet supports medical treatment and does not replace it. For symptoms, causes and treatment, see our page on ulcerative colitis.

Get medical help promptly if you have more than six bloody bowel movements a day, a fever, signs of dehydration such as dizziness or dark urine, or weight loss you cannot explain. These can signal a severe flare and need a clinician, not a change of diet^[3][2].

What does the research say about a UC diet?

The evidence supports a few clear points and leaves most food-by-food questions open.

• No diet reliably prevents flares. The AGA's 2024 update says no diet has consistently lowered flare rates in adults with IBD^[1]. ESPEN's 2023 guideline adds that there is no "IBD diet" that can be generally recommended to bring active disease into remission^[4].
• Mediterranean-style eating is the default. The AGA recommends fresh fruits and vegetables, monounsaturated fats, complex carbohydrates and lean proteins, and less ultra-processed food, added sugar and salt^[1].
• Red and processed meat is the main exception. Cutting back on them is the one food change that guidelines single out for ulcerative colitis^[1][5].
• Most trials are small. A Cochrane review of 18 trials (1,878 people, only five in ulcerative colitis) concluded that the effects of dietary changes on IBD are uncertain^[6]. A 2023 meta-analysis of 14 ulcerative colitis trials leaned in favor of diet but called the field "evolving"^[7].

The NIDDK says researchers have not found that specific foods cause or worsen ulcerative colitis, and suggests a food diary to spot your own triggers^[8]. The same page notes that healthier diets are linked to a lower risk of developing IBD in the first place^[8].

What should you eat during a UC flare?

In a flare, aim for enough calories and protein while easing the load on an inflamed colon. A UK hospital dietetics page matches each common problem to a food change^[2]:

The same page suggests about 10 g of soluble fiber a day during a flare, from white rice, white pasta, porridge oats, peeled and deseeded fruit and vegetables, and golden linseeds^[2]. Chopping, blending or cooking produce until soft breaks down tough fibers.

Protein needs go up. ESPEN puts protein needs in active IBD at 1.2 to 1.5 g per kg of body weight a day for adults, versus about 1 g per kg in remission^[4]. For an 80 kg adult, 1.2 g per kg is about 96 g a day, from foods such as eggs, chicken, turkey, fish, tofu and dairy^[2].

If your doctor asks you to follow a low-residue or low-fiber diet for a short period, our low-fiber diet guide explains how those plans work and how to bring fiber back afterwards. If you can eat normally during a flare without problems, the hospital page says to keep doing so^[2].

What to eat with UC in remission

In remission, the goal shifts from resting the gut to eating a wide, mostly whole-food diet. The AGA's Mediterranean advice applies here, and ESPEN says to follow healthy eating patterns while avoiding your own known triggers^[1][4].

The IOIBD found too little evidence to recommend changing fruit or vegetable intake for ulcerative colitis specifically, so build fiber back gradually and at your own pace^[5]. There was also too little evidence to restrict wheat or gluten^[5].

Which foods should you avoid with colitis?

The best-supported limit is red and processed meat. Several additives are on cautionary lists too, but that evidence is weaker.

The meat signal comes mostly from one prospective study of 191 people in remission. Those in the top third of red and processed meat intake had 5.19 times the odds of relapse within a year, and high alcohol intake had 2.71 times the odds^[10]. A smaller later study did not confirm the red meat link, which is why the IOIBD rates the evidence as low^[5].

For carrageenan, the only human trial is tiny. Of 12 people in remission who finished it, 3 who took carrageenan capsules relapsed versus none on placebo^[11]. ESPEN more broadly says avoiding ultra-processed food and emulsifiers can be recommended, based on early data^[4].

Personal triggers matter too. Some people find fruit, nuts, spicy or fatty foods worsen symptoms, and some develop temporary lactose intolerance during a flare^[2]. See our page on lactose intolerance if dairy seems to be the issue.

Cutting foods unnecessarily can lead to deficiencies, so test one suspect food at a time and reintroduce it^[2].

Do special diets work for UC?

Some show early promise, but none has strong enough evidence to replace medication^[6].

• Mediterranean diet. In a 12-week trial of 28 adults with quiescent ulcerative colitis, 20% on a Mediterranean pattern had fecal calprotectin above 100 µg/g at the end, versus 75% on their usual diet^[9]. Calprotectin is a stool marker of gut inflammation; our calprotectin test guide explains it.
• Low-fat, high-fiber diet. In a crossover trial of 17 people, a catered diet with 10% of calories from fat improved quality of life and lowered serum amyloid A, an inflammation marker, from 7.99 to 4.50 mg/L over 4 weeks^[12].
• UC exclusion diet. In the CRAFT UC trial of 62 adults with active disease that had not responded to medication, 40% (6 of 15) on the diet alone reached steroid-free remission at week 8, versus 11.8% after fecal transplant alone. The difference was not statistically significant, and the trial was stopped early for futility^[13].
• Low FODMAP diet. It may help gas and bloating that continue when the disease is quiet. In 52 people with IBD in remission, 52% reported adequate symptom relief versus 16% on a control diet, with no change in inflammation markers^[14].
• Anti-inflammatory, carrageenan-free and milk-free diets. None clearly reduced relapse in small trials of inactive ulcerative colitis^[6][7].

ESPEN adds that trial data on the specific carbohydrate, paleo, gluten-free and vegetarian diets are still lacking or uncertain^[4]. Restrictive diets are best tried with a dietitian. The AGA suggests that everyone newly diagnosed with IBD has access to one^[1].

Can probiotics, curcumin or fish oil help?

Some supplements have trial data, but only as add-ons to standard care^[4][15].

• Probiotics. ESPEN says selected probiotics can be used as an alternative to 5-ASA (mesalamine-type) drugs in mild-to-moderate active ulcerative colitis when those drugs are not tolerated^[4]. The trials it cites include Escherichia coli Nissle 1917, which matched mesalamine for keeping remission. This is a specific strain decision for your gastroenterologist, not a reason to buy any probiotic. Our Escherichia coli page covers the species.
• Prebiotic supplements. ESPEN says these cannot be routinely recommended for ulcerative colitis^[4].
• Curcumin. In a trial of 50 adults with mild-to-moderate active disease that had not settled on mesalamine, 53.8% who added 3 g a day of curcumin reached remission at 4 weeks, versus none on placebo^[15]. It was one small, one-month trial.
• Fish oil. ESPEN advises against omega-3 supplements for keeping IBD in remission, based on high-quality evidence. Eating oily fish is the preferred route^[4][5].

Check any supplement with your care team before starting it.

What does a good meal plan look like for someone with colitis?

This example flare day uses only foods and timings from the hospital dietetics page we read^[2]. Adjust portions to your appetite.

In remission, the same structure can expand to whole grains, salads and legumes as you tolerate them, following the Mediterranean pattern above^[1].

How does diet affect the gut microbiome in UC?

People with ulcerative colitis tend to have fewer butyrate-producing bacteria. In a Belgian study of 127 patients and 87 controls, Roseburia hominis and Faecalibacterium prausnitzii were lower in ulcerative colitis, and both fell further as disease activity rose^[16]. Butyrate is one of the short-chain fatty acids these bacteria make, and total short-chain fatty acids were also lower in the patients^[16].

Diet trials suggest food can shift these microbes. The Mediterranean diet raised fecal butyrate and acetate and increased Ruminococcus bromii, a species linked to short-chain fatty acid production^[9]. The low-fat, high-fiber diet raised F. prausnitzii to 7.20% of stool bacteria, versus 5.37% on the comparison diet^[12].

Restrictive diets can push the other way. After 4 weeks of low FODMAP eating, people with IBD had less Bifidobacterium longum, Bifidobacterium adolescentis and F. prausnitzii than those on a control diet^[14]. That is one reason to treat low FODMAP as a short trial.

Our ulcerative colitis microbiome protocol and our page on inflammatory bowel disease go further.

Which nutrients are easy to run low on?

Ulcerative colitis can reduce appetite and nutrient intake, and in children poor intake may affect growth^[8].

• Iron. The AGA says everyone with IBD should be monitored for iron and vitamin D deficiency^[1]. ESPEN recommends iron supplements when iron deficiency anemia is present^[4].
• Vitamin D and calcium. ESPEN advises checking vitamin D in active disease or during steroid treatment, with calcium and vitamin D if needed to protect bone^[4]. The hospital page advises 1,000 mg of calcium a day, including fortified alternatives if you cut dairy^[2].
• Folate and B12. These can run low during flares, so the hospital page lists them alongside iron^[2].
• Overall calories. The AGA recommends regular screening for malnutrition, including unintended weight loss and muscle loss^[1].

When to see a doctor

Contact your gastroenterologist promptly, and seek urgent care for severe symptoms, if you have:

• more than six bowel movements a day with blood most of the time, or more than ten bloody ones, which the NIDDK classes as severe or extremely severe disease^[3];
• fever, nausea or vomiting, or unexplained weight loss^[3];
• thirst, dry mouth, dark urine or dizziness, which can mean dehydration^[2];
• plans to start an exclusion, low FODMAP or other restrictive diet. Ask for a registered dietitian first^[1].

New blood or mucus in your stool also deserves a check; our guide to mucus in stool covers what it can mean. If you have Crohn's disease rather than ulcerative colitis, our Crohn's disease diet guide covers the exclusion diets used there.

This article is for general educational purposes and is not medical advice. Diet can support but does not replace treatment for ulcerative colitis, and results from small trials may not apply to you. Talk to a qualified healthcare professional or registered dietitian before changing your diet or starting supplements, particularly if you are pregnant, immunocompromised, taking prescription medication, or managing a diagnosed condition. Do not stop or change prescribed medication because of a diet.