Foods high in insoluble fibers, lactose, and sugars can all trigger unpleasant ulcerative colitis symptoms. However, every person is different and working with a doctor can help identify which foods a person with ulcerative colitis should avoid.

Ulcerative colitis (UC) is a chronic, inflammatory disease of the colon and rectum. It’s one of two main inflammatory bowel diseases, the other being Crohn’s disease.

When a person has UC, sores called ulcers develop inside the colon.

Symptoms of the disease include:

Researchers believe UC may result from a number of factors, including dysregulated immune responses, genetic predisposition, genetic predisposition, microbial dysbiosis, epithelial barrier defects, and environmental factors.

A person’s diet and gut bacteria play a role in inflammatory bowel diseases (IBD), but much research into this area is still in its infancy. However, it is clear that a high fiber diet can have significant clinical benefits in people with IBD.

A person should only reduce fiber intake when experiencing acute symptoms like a flare-up or strictures.

During a flare-up of symptoms, a low fiber diet may be helpful in reducing material in the colon, thereby reducing symptoms and helping you recover more quickly.

People with IBD respond differently to dietary intervention. Some do well on high fiber diets, while others can only tolerate specific types of higher fiber foods.

It’s best to work with a medical professional, such as a registered dietitian, to develop a diet that works best for managing symptoms and supporting overall health and that not everyone with IBD will do well on the same diet.

During a flare, a healthcare team typically suggests certain dietary modifications, which may include the following:

During a flare-up, people with UC tend to find it difficult to digest foods that contain a lot of fiber.

Whole grain breads, cereals, and pastas

Whole grain flour is high in fiber because it hasn’t had the germ or bran removed.

It’s important to avoid eating food made from any whole grain flour, such as:

  • breads
  • cereals
  • pastas
  • noodles
  • macaroni

During flare-ups, choosing white breads and pastas made from enriched white flour are better options, unless you have a gluten intolerance.

Flour is “enriched” when nutrients lost during the germ and bran removal process are replaced. Cereals like puffed rice, corn flakes, and cream of wheat are also lower in fiber.

Brown rice and other whole grain starches

Try to avoid eating the following whole grain foods:

  • brown rice
  • quinoa
  • buckwheat
  • oats
  • wild rice

These grains still have the fibrous endosperm, germ, and bran that can irritate UC and may trigger a flare-up.

It’s also helpful to avoid eating these other whole grains:

  • plain barley
  • millet
  • wheat-berries
  • bulgur wheat
  • spelt

A better option for those with UC is well-cooked white rice.


Nuts, including those cooked into other foods or made into flours, should be on your do-not-eat list if you have been prescribed a low fiber diet for UC. The fiber in nuts can be very hard to digest.

It’s best to not consume the following nuts:

  • walnuts
  • hazelnuts
  • pecans
  • cashews
  • almonds
  • macadamia nuts
  • peanuts
  • pistachios


Like nuts, seeds can also aggravate symptoms. Seeds are a type of insoluble fiber, which can cause bloating, diarrhea, gas, and other irritating side effects.

Some seeds to avoid include:

  • sesame seeds
  • flaxseeds
  • millet
  • pine nuts
  • sunflower seeds
  • pumpkin seeds
  • wild rice

Dried peas, beans, and lentils

Legumes, including beans, lentils, and peas, are high fiber, high protein foods. Because of the indigestible sugars in beans, they’re also notorious for causing gas. If you are experiencing a UC flare-up, you’ll want to pass on the following:

  • all beans, including chickpeas
  • adzuki beans
  • soy nuts, including soybeans and edamame

Fibrous fruits

While they are healthy for you, most fruits contain a lot of fiber. Fruits belong on the list of foods to avoid if they are:

  • raw
  • dried
  • have seeds that can’t be removed (like most berries)

You can eat fruit that’s been peeled and if the flesh has been cooked until very soft, such as applesauce. You can also eat canned fruits, but choose the type packed in water or in their own juice to avoid excess sugar.

Most fruit juices with the pulp removed are typically OK to drink. Skip prune juice since it’s very high in fiber.

Fibrous vegetables

Like fruits, vegetables are also full of fiber. You should Include them in your diet only if they are:

  • skinned or peeled
  • have no seeds
  • are cooked until soft

Avoid all raw or undercooked vegetables, including corn. It’s fine to consume canned vegetables and potatoes, as long as the skin has been discarded. Try pureed vegetable soups for an easy way to digest vegetables.

Because vegetables provide many important nutrients, it’s important to include them in your diet.

A common food intolerance among those with UC is lactose. Lactose is a sugar found in most dairy products.

If you suspect dairy may be a symptom trigger for you, remove all types of dairy, including butter, milk, yogurt, and cheese, for at least 4 weeks.

Work closely with your doctor or dietitian to help you learn how to follow an elimination diet to help identify and remove foods that trigger or worsen your symptoms.

Sugary foods such as candies, high-sugar juices and sugary baked goods can all contribute to UC flares.

A high-sugar diet can also increase a person’s susceptibility to UC flares when they are in periods of remission.

Non-absorbable sugars

Many sugar-free foods contain sugar alcohols that the body cannot digest. Common nonabsorbable sugars include mannitol and sorbitol.

Foods containing nonabsorbable foods include:

  • sugar-free gum
  • sugar-free drinks
  • fruits such as peaches, pears, and plums

Eating a low fat diet can reduce a person’s risk of developing UC and reduce symptoms in those with the condition.

Limiting the following foods can help people manage UC in remission and reduce severity of flares:

  • butter
  • coconut and other oils
  • margarine
  • cream
  • fried foods

In addition to making careful choices about the foods you eat with UC, it’s also important to reduce your consumption of drinks that may worsen your UC symptoms. Studies show that soft drinks cause UC symptoms to increase. These types of drinks include soda and other beverages with a lot of sugar and artificial sweetener content.

Trying to limit consuming soft drinks can be helpful in managing your condition.

The Crohn’s and Colitis Foundation states that spicy foods can worsen UC flares. However, research in this area is limited.

In fact, a 2019 review suggests that capsaicin, which is the active component in hot chilies that gives the feeling of spice, can actually reduce intestinal inflammation and IBD symptoms.

A food intolerance that is becoming more common among those who have digestive symptoms is gluten.

Gluten is one protein found in wheat, rye, and barley. Gluten is not only found in common foods like bread and pasta, but it’s also added to prepared products like condiments, sauces, soups, and proteins.

If you suspect gluten may be a symptom trigger for you, remove all types of gluten-containing grains, cereals, baked goods, and other products for at least 4 weeks.

While your diet may be restricted if you’re experiencing a UC flare-up, it does not have to be boring. Focus on the foods you can eat rather than the foods you should avoid. The foods you can eat (unless you have an identified allergy or intolerance to any of the foods below) include:

  • low fiber fruits
  • refined, white carbohydrates
  • lean proteins
  • well-cooked, skinless vegetables
  • skinless, seedless fruits

It’s important to remember that your diet plays a vital role in your overall health. Use this information as a guide to help you recover from acute symptoms like diarrhea, limitations (strictures), or after surgery.

To increase your chances of remission, gradually reintroduce high fiber foods, since fiber protects the health of your colon tissue as well as your gut bacteria.

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