Although weight loss is a common symptom of ulcerative colitis (UC), the condition can sometimes cause weight gain and bloating. This can be due to certain medications, difficulty eating certain foods, and more.

UC is a type of inflammatory bowel disease (IBD) that causes symptoms such as diarrhea, abdominal pain, and blood in stools.

If a person believes they are experiencing weight gain and bloating due to UC, it is best to contact a doctor for advice. A doctor can advise on steps to help manage weight and recommend foods to eat and avoid.

Read on to learn more about the possible links between UC, weight gain, and bloating. This article also looks at food that may help manage symptoms.

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UC may lead to weight gain in some people. There are several possible causes of this.

Difficulty eating certain foods

Eating a well-balanced diet can help a person maintain a moderate weight. However, when certain foods trigger flare-ups, this can make eating a nourishing diet more difficult.

Some people with UC may have issues eating certain foods that typically form part of a nutritious diet, such as:

  • whole grains
  • vegetables
  • fruits with skin
  • seeds
  • nuts

Different foods can trigger flare-ups for different people. Keeping a food diary can help a person monitor which foods may trigger or worsen a flare-up.

Difficulty exercising regularly

Getting enough regular exercise or physical activity can also help a person maintain a moderate weight.

The Centers for Disease Control and Prevention (CDC) recommends adults aim for at least 150 minutes of moderate-intensity physical activity or 75 minutes of vigorous-intensity physical activity per week.

Some symptoms of UC may make it more difficult for a person to engage in regular exercise. People with UC may experience abdominal pain, feel fatigued, and go to the bathroom a lot. This combination of symptoms can lower energy levels and affect the ability to exercise.

A 2018 review suggests that exercising is generally safe and beneficial for people with IBD, such as UC. A person’s doctor can help them find ways to incorporate physical activity or exercise into their routine.

The Crohn’s & Colitis Foundation recommends low impact or moderate activities such as:

  • brisk walking
  • swimming
  • bicycling
  • yoga
  • rowing
  • elliptical use


Some medications for UC can cause a person to gain weight. These include:


Corticosteroids, such as prednisone, may cause a person to gain weight. Long-term use may also lead to a decrease in healthy muscle mass.


TNF-alpha inhibitors, a type of biologic medication, are a common treatment for UC. They may lead to weight gain.

For instance, some evidence links the common treatment infliximab (Remicade) with weight gain.

A 2020 study found that 59% of people taking infliximab for Crohn’s disease, another IBD, experienced weight gain within the first 6 weeks. Additionally, 73% of people experienced weight gain within 3 months, and this increased to 76% within 12 months.

However, researchers of a 2022 study did not observe long-term weight gain in people taking infliximab as part of maintenance therapy for UC and Crohn’s disease.

More research is necessary to confirm this effect.

UC can lead to bloating and gas in some people. This may be due to:

  • issues with absorbing or digesting certain foods, such as starchy or sugary foods
  • constipation
  • changes in the gut’s balance of bacteria
  • gut sensitivity
  • lactose intolerance
  • irritable bowel syndrome (IBS), which affects around 3 in 10 people with UC

Undergoing surgery for UC may also lead to bloating and gas. This can happen as a result of scar tissue after the operation.

In rare cases, bloating can happen as a result of toxic megacolon. Toxic megacolon is a rare but serious complication that can develop in cases of severe UC. It happens when gas becomes trapped due to inflammation in the colon. Toxic megacolon requires immediate medical attention.

Learn more about the possible complications of moderate to severe UC.

Certain foods may trigger or worsen a UC flare-up. Avoiding these foods may help a person manage their symptoms and weight.

Trigger foods may be different for each person. However, the Crohn’s & Colitis Foundation recommends that people with UC avoid the following foods:

  • Dairy products: These include milk, cream, cheese, and soft cheeses.
  • Sugary foods: Examples include candy, pastries, and juices.
  • High fat foods: Butter, cream, and fatty, fried, or greasy foods can contribute to weight gain.
  • Alcoholic drinks: A person may wish to exclude beer, wine, and spirits from their diet or moderate their intake.

Learn more about foods to eat and avoid with UC.

People with UC can identify foods they can tolerate that also contribute to a balanced diet.

These foods will vary among individuals but may include:

  • Low fiber fruits: These include bananas, cantaloupes, and honeydew melons.
  • Lean protein: Examples include fish, lean cuts of pork, white meat, eggs, and firm tofu.
  • Refined grains: People may be able to tolerate sourdough and gluten-free bread, white pasta and rice, and oatmeal.
  • Vegetables: The ideal options are grilled, steamed, or boiled vegetables.

If a person is adding new foods to their diet, they may wish to keep a food diary to monitor any changes to their symptoms. A registered dietitian can also help them to find ways to incorporate foods that may be beneficial.

Learn about snacks for UC.

People with UC who are concerned about gaining weight can take steps to help prevent it. These include:

  • eating a varied, nutritious diet
  • measuring servings and managing portion sizes
  • avoiding skipping meals
  • keeping a food diary to monitor daily calorie intake and UC symptoms
  • staying hydrated throughout the day, ideally with water
  • getting enough regular physical activity or exercise

A person’s doctor can provide more advice on ways to lose weight safely.

Learn more about losing weight with UC.

UC may cause weight gain in some people. This can be due to the types of food a person consumes, as well as reduced physical activity due to symptoms such as stomach pain and fatigue.

Some UC medications may also cause a person to gain weight.

A person may wish to try eating a varied, nutritious diet and getting regular exercise or physical activity to help prevent weight gain. They may also wish to consider contacting their doctor for advice.