Ulcerative colitis (UC) is a type of inflammatory bowel disease that causes symptoms such as diarrhea, abdominal cramping, and bloody stools. Although weight loss is a common symptom of UC, the condition can sometimes cause a person to gain weight.

UC is a relatively common long-term condition that causes the immune system to react abnormally. This immune reaction produces inflammation in the colon and causes ulcers to appear in the colon’s inner lining.

A person with UC may experience some of the following symptoms:

UC can cause various other symptoms, which include fatigue, a loss of appetite, fever, nausea, and anemia.

These symptoms often only appear during flare-ups, which usually appear before a period of remission. When a person is in remission, they may experience few or no symptoms.

Although it is common to lose weight as a result of UC, some people may gain weight due to the disease.

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UC can cause both weight gain and weight loss.

UC can affect a person’s ability to digest food properly and absorb nutrients from it. Due to this, it can lead to serious vitamin deficiencies and malnutrition. Both of these effects can cause a person with UC to lose weight.

However, there are several reasons why UC can also cause a person to gain weight. These include:

  • issues eating certain foods
  • difficulty exercising
  • certain UC medications that may promote weight gain

There is not much research into whether UC can cause bloating. However, a 2016 study found that people with inflammatory bowel disease, which includes UC, had significantly worse belly pain, gas, and bloating than people in the general population.

Bloating vs. weight gain

Bloating is different than weight gain. Weight gain occurs over time when a person regularly eats more calories than they use through exercise and normal bodily activities.

Bloating occurs when a person’s gastrointestinal tract is full of air or other gases.

When bloated, a person may find that their stomach feels full and tight as though they have eaten a big meal. This sensation can be uncomfortable or even painful, and it may cause a person’s stomach to appear bigger than usual.

Learn about 18 ways to reduce bloating here.

There are several possible causes of weight gain in people with UC.

Difficulty eating certain foods

Some people with UC may have issues eating certain foods that typically form part of a nutritious diet, such as whole grains, cruciferous vegetables, fruits with skin and seeds, and nuts. Different foods can trigger flare-ups for different people.

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

Learn more about the right diet for ulcerative colitis here.

Difficulty exercising regularly

Exercise is another key factor in helping a person maintain a moderate weight.

The Centers for Disease Control and Prevention (CDC) state that adults should get at least 150 minutes of moderate intensity physical activity or 75 minutes of vigorous intensity physical activity a 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 impair the ability to exercise.

Some UC medications can cause weight gain

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


Corticosteroids, such as prednisone, may cause a person to gain weight. The long-term use of these drugs may also lead to a decrease in healthy muscle mass.


Biologics, or anti-tumor necrosis factor agents, are a common treatment for UC and may lead to weight gain.

For instance, some evidence links the common biologic treatment infliximab (Remicade) with weight gain. A 2018 study suggests that Remicade can cause weight gain in people with UC if they use it for an extended period. However, more research is necessary to confirm this effect.

Eating a balanced diet is key to maintaining a moderate weight.

The Crohn’s & Colitis Foundation recommends that people with UC avoid a number of possible trigger foods to minimize the likelihood of flare-ups.

Some of these foods may also contribute to weight gain. For example:

  • 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.

People with UC can identify foods that they can tolerate that are also healthy and 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 best options are grilled, steamed, or boiled vegetables.

Learn more about what to eat to reduce colon inflammation here.

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

  • eating a varied, nutritious diet
  • eating between four and six small meals each day
  • staying hydrated throughout the day
  • engaging in regular exercise if possible
  • going for one short brisk walk each day
  • measuring servings and controlling portion sizes
  • keeping a food diary to monitor daily calorie intake and UC symptoms
  • preparing healthy meals in advance that include nutritious, well-tolerated foods

Weight loss is a common symptom of ulcerative colitis. However, in some instances, this condition may cause a person to gain weight.

Some people with UC may struggle to eat a balanced diet, while others may be unable to exercise regularly 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 to prevent weight gain.