Nutrition Diet: What Can You Eat During an Ulcerative Colitis Flare-Up?

October 18, 2025 •

4 min read

According to the Crohn's & Colitis Foundation, common trigger foods for ulcerative colitis (UC) vary widely among individuals. Knowing what can you eat during an ulcerative colitis flare-up is crucial, as making temporary dietary modifications is a key strategy for managing symptoms and preventing potential nutrient deficiencies.

Quick Summary

During an ulcerative colitis flare, a temporary, low-fiber diet focusing on easy-to-digest foods can help reduce symptoms like diarrhea and abdominal pain. Emphasis is placed on lean proteins, refined grains, and cooked, skinless vegetables, while avoiding personal trigger foods such as high-fiber items, dairy, and spicy dishes.

Key Points

Prioritize low-fiber foods: During a flare, focus on easy-to-digest items like refined grains, ripe bananas, applesauce, and cooked, skinless vegetables.
Choose lean protein: Opt for tender, cooked poultry, fish, and eggs, which are great sources of protein without irritating the colon.
Stay hydrated: Drink plenty of fluids like water and clear broths, especially with diarrhea, to prevent dehydration.
Avoid personal triggers: Common irritants like high-fiber foods, dairy (if intolerant), greasy foods, and caffeine should be temporarily avoided based on your personal response.
Opt for smaller, frequent meals: Eating 5-6 smaller meals per day can be easier on the digestive system than three large ones.
Cook food gently: Baking, steaming, or grilling can make vegetables and proteins easier to digest than frying.
Track your food and symptoms: A food journal helps pinpoint specific foods that trigger or worsen your symptoms.

Understanding Your Diet During a Flare

When ulcerative colitis becomes active, the lining of the colon is inflamed and may have sores, making it highly sensitive to irritation. The goal of a flare-up diet is not to cure the condition, but to provide nutritional support while minimizing symptoms and allowing the bowel to rest. During this period, healthcare providers often recommend a temporary low-fiber or low-residue diet, which involves eating foods that are easily digestible and produce less undigested waste, or "residue," in the stool.

Low-Fiber, Easy-to-Digest Food Choices

During a flare, focusing on foods that are gentle on the digestive tract can help reduce irritation and discomfort. This includes consuming lean proteins, refined grains, and cooked, skinless produce.

Lean Proteins

Fish: Skinless, lean fish like salmon, mackerel, and tuna (packed in water) are excellent sources of protein and omega-3 fatty acids, which have anti-inflammatory properties.
Poultry: Plain, skinless chicken or turkey, prepared by baking, grilling, or steaming, is a well-tolerated and nutrient-dense option.
Eggs: Scrambled or boiled eggs are a good source of protein and are generally not a common trigger for UC symptoms.
Tofu: For a plant-based option, firm tofu can provide necessary protein.

Refined Grains and Starches

White Rice and Pasta: These refined options are easier to digest than whole grains.
White Bread: Plain, white bread or toast without seeds or nuts is a suitable carbohydrate source.
Oatmeal and Refined Cereals: Cooked oatmeal and low-fiber cereals like cornflakes or puffed rice are often well-tolerated.
Potatoes: Thoroughly cooked potatoes, with the skin removed, are a soft, starchy vegetable choice.

Cooked Fruits and Vegetables

Low-Fiber Fruits: Soft, peeled, and cooked fruits like bananas, melons, applesauce, and canned peaches are often well-tolerated.
Cooked Vegetables: Thoroughly cooked, non-cruciferous vegetables without skin or seeds, such as carrots, squash, and asparagus tips, are easier to digest.

Common Trigger Foods to Avoid

Identifying and temporarily eliminating certain foods is crucial for managing flare-ups, though specific triggers vary by person.

High-Fiber Foods: Whole grains, nuts, seeds, popcorn, and raw vegetables contain insoluble fiber that can irritate an inflamed bowel and increase cramping and diarrhea.
Dairy: Many people experience lactose intolerance during a flare. Limiting or avoiding milk, soft cheeses, and ice cream can help reduce symptoms.
High-Fat and Spicy Foods: Greasy, fried foods and spicy dishes can irritate the digestive tract.
Caffeine, Alcohol, and Sugary Drinks: These can stimulate the intestines and worsen diarrhea and inflammation. Sugary fruit juices can also contribute to watery stools.

Dietary Management During a Flare-Up vs. Remission


Feature	During a Flare-Up	During Remission
Fiber Intake	Low. Focus on refined grains and cooked, peeled produce to minimize residue and bowel irritation.	Increased. Gradually reintroduce fiber from fruits, vegetables, and whole grains as tolerated to support gut health.
Grains	Refined. Opt for white rice, white bread, and plain cereals for easier digestion.	Mixed. Can tolerate whole grains like brown rice, whole wheat bread, and quinoa as symptoms improve.
Fruits & Veggies	Cooked, Peeled. Prioritize soft, low-fiber fruits and thoroughly cooked, skinless vegetables.	Varied. Slowly add back raw fruits, vegetables with skins, and seeds to increase nutrient intake.
Meal Frequency	Smaller, Frequent. Eat 5-6 small meals per day to reduce the burden on your digestive system.	Regular. Can typically return to 2-3 larger meals, depending on personal tolerance.
Hydration	Critical. Drink plenty of water and clear broths, especially if experiencing diarrhea, to prevent dehydration.	Sustained. Continue adequate fluid intake as a standard health practice.

The Importance of Hydration and Nutrition

During a flare, diarrhea can quickly lead to dehydration and electrolyte imbalance. Drinking ample fluids like water, broth, and diluted juices (without pulp) is essential. Furthermore, appetite loss and selective eating during flares put individuals at a higher risk for nutritional deficiencies, particularly calcium, iron, and B vitamins. Eating small, frequent, nutrient-dense meals can help combat this. In some cases, a doctor or registered dietitian may recommend oral nutritional supplements to ensure adequate intake.

Practical Tips for Managing Your Diet

Keep a food journal: Track your food intake and any corresponding symptoms to identify your specific triggers.
Eat smaller meals: Instead of three large meals, try eating five or six smaller, more manageable portions throughout the day.
Cook and chew thoroughly: Steaming, baking, and grilling foods make them easier to digest. Chew your food slowly and completely to aid digestion.
Prepare ahead: Have easily digestible foods and meal components on hand for when symptoms are at their worst.
Gradual reintroduction: As you move towards remission, reintroduce higher-fiber foods slowly to test tolerance.

Conclusion: Listen to Your Body

Managing diet during an ulcerative colitis flare-up is a personalized process. While general guidelines exist, every individual's tolerance is different. The ultimate strategy is to listen to your body, focus on easy-to-digest, nutrient-rich foods during active symptoms, and work closely with your healthcare team to ensure your nutritional needs are met. Remember that dietary changes complement, but do not replace, medical treatment.

For more resources and guidance on managing UC, visit the Crohn's & Colitis Foundation.

Frequently Asked Questions

Yes, following a low-fiber or low-residue diet is often recommended during a flare-up. It reduces the amount of indigestible food waste that irritates the inflamed bowel, which can help minimize symptoms like cramping, bloating, and diarrhea.

Dairy tolerance varies. Some individuals, particularly during a flare, may become temporarily lactose intolerant and find that milk and other dairy products worsen symptoms. If this is the case, lactose-free or fortified plant-based milk alternatives are often good substitutions.

No, high-fiber foods are typically only avoided during an active flare-up. When in remission, gradually reintroducing high-fiber foods can be beneficial for gut health and may even help maintain remission.

Hydration is critical. Water, clear broths, and diluted juices without pulp are recommended. Avoid carbonated drinks, caffeine, and alcohol, as these can irritate the digestive tract and worsen symptoms.

While often used interchangeably, a low-residue diet can be more restrictive than a low-fiber diet. A low-fiber diet limits high-fiber items, whereas a low-residue diet also restricts foods like dairy that produce stool waste. A healthcare provider can determine the appropriate approach.

Yes, eggs are generally considered safe to eat during a flare-up. They are an easily digestible source of protein and are not typically a trigger food for ulcerative colitis.

Eating smaller, more frequent meals can help maximize nutritional intake when your appetite is low. Focus on nutrient-dense, easily digestible foods, and talk to your doctor or a registered dietitian about potentially using nutritional supplements.