What to eat during an ulcerative colitis flare

When UC symptoms spike — more diarrhea, cramping, urgency, and blood — what you eat becomes especially important. The inflamed gut is more sensitive and has less capacity to process difficult foods. Eating the wrong things can increase discomfort and bowel frequency; eating thoughtfully can help reduce stress on an already irritated digestive system.

This guide covers what tends to help and hurt during a flare, and what to focus on to keep your nutrition up while your gut is struggling. For a broader guide to eating with UC in remission as well, see our full ulcerative colitis diet guide.

What to Eat During Ulcerative Colitis Flare Up

Knowing what to eat during ulcerative colitis flare up is one of the most immediate practical questions people face when symptoms spike. The short answer is: low-residue, low-fiber, easily digestible foods that minimize work for your inflamed colon. This means shifting away from your normal diet — even a healthy one — and temporarily focusing on foods that are gentle and easy to process.

The foundation of what to eat during ulcerative colitis flare up is a low-residue diet. This includes white rice, plain boiled or baked chicken or fish, scrambled or boiled eggs, bananas, applesauce, plain crackers, well-cooked carrots without skin, and clear broths. These foods are bland, but that is the point — they pass through the digestive system without triggering excessive gut activity, giving your colon some relief while it is inflamed.

Meal timing and portion size matter as much as food choice. Eating small amounts frequently — five or six small meals rather than two or three large ones — reduces the digestive demand on your gut at any one time. Large meals stimulate stronger gut contractions, which worsens cramping and urgency. Small, frequent meals keep nutrition coming in without overwhelming a system that is already under stress.

Staying hydrated is a non-negotiable part of managing what to eat during ulcerative colitis flare up. Diarrhea causes significant fluid and electrolyte loss. Water alone may not be enough — oral rehydration solutions or electrolyte drinks help replace sodium and potassium that diarrhea depletes. Make hydration a conscious, consistent effort throughout the day, not just when you feel thirsty.

The goal of eating during a flare

The goal is not perfection — it is minimizing gut irritation while staying nourished and hydrated. During a severe flare, you may have a reduced appetite, which is normal. Forcing yourself to eat large meals can worsen cramps and urgency.

Focus on:

• Small, frequent meals rather than three large ones
• Soft, low-residue foods that require less gut work
• Staying hydrated
• Not skipping meals entirely, even if appetite is low

Foods that tend to be better tolerated during a flare

Cooked, well-softened vegetables

Raw vegetables are too high in insoluble fiber during a flare. Switch to:

• Peeled, well-cooked carrots
• Peeled, mashed or boiled potatoes
• Cooked zucchini or squash (without seeds)
• Cooked green beans (no skins)
• Butternut squash, steamed and soft

Avoid: raw salads, broccoli, cabbage, cauliflower, corn, onions, peppers.

Refined grains and starches

Lower-fiber, refined carbohydrates are easier to digest during active inflammation:

• White rice (plain, well-cooked)
• Plain white bread or toast
• Plain crackers (like saltines)
• Plain pasta or white-flour noodles
• Plain oatmeal (cooked soft, not loaded with seeds or dried fruit)
• Plain boiled or mashed potato (no skin)

Avoid: whole grain breads, high-fiber cereals, brown rice, bran products.

Lean proteins

Protein is important for healing but should come from easy-to-digest sources:

• Skinless chicken breast (baked, boiled, or lightly sautéed)
• White fish (cod, tilapia, flounder) — baked or steamed
• Eggs (scrambled, boiled, or poached — not fried)
• Firm tofu (plain)
• Smooth nut butters (if tolerated) — peanut butter in small amounts

Avoid: red meat, processed meats, fried or fatty meats, spicy sausages.

Soft fruits (ripe and peeled)

• Ripe banana (one of the most universally tolerated fruits during a flare)
• Canned peaches or pears in juice (no skin)
• Cooked applesauce (unsweetened)
• Ripe melon (no rind)

Avoid: citrus fruits, berries with seeds, dried fruit, raw apple with skin.

Broths and soups

• Clear chicken or vegetable broth — helps with hydration and provides some electrolytes
• Low-fat soup with soft noodles and soft vegetables
• Bone broth (many people find this soothing)

Dairy — with caution

Whether to include dairy depends on individual tolerance. Some people with UC also have lactose sensitivity; others tolerate it fine.

• Low-fat yogurt may be tolerated by some
• Probiotic yogurt is popular though evidence for it in UC is not definitive
• Cheese in small amounts (especially aged, lower-lactose cheeses) may be fine for some

If you suspect dairy worsens your symptoms, eliminate it during the flare and reintroduce after.

Best Foods to Eat During a Colitis Flare Up

Understanding the best diet for colitis flare up means looking beyond a simple list of allowed foods and thinking about which foods actively support recovery. The best foods during a colitis flare up are those that are easy to digest, provide useful nutrition without gut-irritating fiber, and help maintain the hydration and protein levels your body needs while it is fighting inflammation.

White rice is arguably the single most universally recommended food during a UC flare. It is low in fiber, easy to digest, provides carbohydrate energy, and is essentially neutral in terms of gut irritation. Plain, well-cooked white rice — eaten in small portions — is a cornerstone of the best diet for colitis flare up and should form the base of most meals during active disease. Pairing it with a small amount of plain boiled chicken or a scrambled egg gives you a complete, low-irritation meal.

Plain chicken and fish are the best protein sources during a flare. Skinless chicken breast — baked or boiled, without spices or sauces — and white fish like cod or tilapia are lean, easy to digest, and provide the amino acids your body needs for tissue repair and immune function. Eggs, especially scrambled or boiled rather than fried, are another excellent protein option that most UC patients tolerate even during active disease. Getting adequate protein is important during a flare because the body’s protein requirements increase with active inflammation.

Bananas stand out as possibly the best single food for a UC flare. They are soft, low in fiber, rich in potassium (an electrolyte commonly lost through diarrhea), easy to eat even with a suppressed appetite, and virtually universally tolerated. Applesauce and canned fruits in juice without skins round out the safest fruit options. Clear broths and oral rehydration drinks are essential for maintaining fluid balance when diarrhea is frequent — these belong on any list of the best foods to eat during a colitis flare up even though they are not solid food.

Foods to avoid during a flare

These tend to worsen symptoms for most people during active disease:

Foods to Avoid During a UC Flare

Beyond the general table above, it helps to understand why certain items are among the foods to avoid during colitis flare up — because understanding the reason makes it easier to apply the principle to foods not on any list.

Raw vegetables and salads are on the avoid list because of their high insoluble fiber content. During a flare, the colon is inflamed and less able to process bulky, rough material. Insoluble fiber increases stool mass and speeds gut transit, which means more bathroom visits, more cramping, and more urgency. Even vegetables that are generally healthy — broccoli, cauliflower, raw onions, cabbage, leafy greens with tough stems — become problematic foods to avoid during colitis flare up. The key exception is well-cooked, peeled, soft vegetables, which are much easier for the inflamed colon to handle.

Whole grains present the same issue as raw vegetables. Brown rice, bran cereal, multigrain bread, oats with added seeds, and high-fiber crackers all contribute insoluble fiber that the inflamed colon struggles to manage. Switching to white rice, white bread, and plain crackers during a flare is not a permanent downgrade — it is a temporary, evidence-based adjustment to reduce gut stress during active disease. You can return to whole grains once symptoms have clearly settled.

Spicy foods, alcohol, caffeine, and carbonated drinks are worth highlighting specifically because many people underestimate how significantly they affect gut behavior. Capsaicin in spicy food directly irritates the mucosal lining. Alcohol increases intestinal permeability and can worsen inflammation. Caffeine stimulates bowel contractions through its effect on gut motility. Carbonated drinks contribute to gas and bloating in an already uncomfortable abdomen. All four should be treated as high-priority foods to avoid during colitis flare up, even in amounts that would not normally cause problems during remission. Fried and heavily fatty foods — fast food, greasy takeout, dishes cooked in large amounts of oil or butter — round out the list of the most consistently problematic foods to avoid during a UC flare.

Staying hydrated during a flare

Diarrhea causes significant fluid and electrolyte loss. Dehydration during a flare can make UC symptoms worse and leave you feeling exhausted.

• Drink water consistently throughout the day
• Oral rehydration solutions (Pedialyte, Liquid IV, or similar) help replace electrolytes lost through diarrhea
• Diluted fruit juice (no citrus), herbal teas, and clear broths count toward fluid intake
• Avoid caffeinated drinks, alcohol, and sugary sodas which can worsen dehydration

Signs of dehydration: dark urine, dizziness, dry mouth, feeling very weak. If you cannot keep fluids down or are severely dehydrated, seek medical attention.

Eating when you have no appetite

During a severe flare, food may be the last thing on your mind. Small, low-irritation options that require minimal effort:

• Plain crackers with peanut butter or a thin spread of cream cheese
• Banana
• Plain oatmeal
• Small bowl of white rice
• Clear soup or broth

Even small amounts of nutrition help support your body’s healing process. If you are unsure what triggered this flare, our guide on understanding a UC flare-up covers common triggers and how flares are assessed by your doctor.

Colitis Flare Up Diet Plan

A practical colitis flare up diet works best when you have a simple framework to follow rather than having to make difficult food decisions when you are already feeling unwell. The colitis flare up diet plan below gives you a repeatable structure you can use throughout the duration of a flare.

Start with the basics. On the first day or two of a flare, scale back to the simplest, lowest-irritation foods you have on hand — white rice, boiled chicken or eggs, banana, plain crackers, and broth. Do not worry about variety at this stage. Consistency and tolerability matter more than eating an interesting diet. Eat small amounts every two to three hours rather than waiting for large meals, and make sure you are drinking enough fluid throughout the day, including oral rehydration solutions if diarrhea is frequent.

Maintain nutrition even if your appetite is low. The instinct when gut symptoms are bad is to stop eating entirely — but this deprives your body of the protein, calories, and micronutrients it needs to fight inflammation. Even very small portions of tolerated foods, eaten frequently, are better than fasting. If eating solid food is very difficult, clear broths, diluted juice, and oral rehydration solutions can maintain fluid and electrolyte intake. This colitis flare up diet approach — small amounts, frequently, focused on the safest foods — should continue until symptoms clearly improve.

Follow the colitis flare up diet consistently until you have had several consecutively better days — a meaningful reduction in stool frequency, significantly less blood, and improved pain and urgency. Many people make the mistake of reintroducing normal foods too quickly after a brief improvement and promptly restimulate their symptoms. Once symptoms have clearly improved, add back foods individually, one new food every one to two days in small portions. Start with slightly higher-fiber cooked vegetables, then whole grains, then other foods. If any food causes a return of symptoms, remove it and wait before trying again. Your gastroenterologist can provide timeline guidance for reintroduction based on how your flare responded to treatment.

Questions to ask your GI doctor

• Should I see a registered dietitian who specializes in IBD to get personalized guidance?
• Am I at risk of any nutritional deficiencies — iron, vitamin D, or B12 — from this flare?
• Are there any supplements I should be taking while my symptoms are active?
• Is my current weight loss during this flare a concern?
• What signs related to my nutrition should prompt me to call your office?
• Once I recover from this flare, are there any dietary restrictions I should maintain?

When to contact a doctor

Contact your healthcare provider if during a flare:

• You are unable to eat or drink for more than 24 hours
• You are losing weight rapidly
• You are showing signs of dehydration
• Your symptoms are worsening despite dietary changes

Dietary adjustments are supportive — they do not replace medical treatment for a UC flare. If symptoms are severe or worsening, contact your gastroenterologist.

This content is for educational purposes only. It does not replace personalized advice from a registered dietitian or your healthcare team.