Irritable bowel syndrome (IBS) is a common gastrointestinal disorder that can cause symptoms such as bloating, abdominal pain, and constipation or diarrhea. Some people with IBS may also have difficulty managing their weight.

However, weight loss or weight gain is rarely a symptom of IBS. Rather, it occurs in response to certain dietary or lifestyle changes that a person employs to manage their IBS symptoms.

There are subtypes of IBS, and the symptoms of the condition can vary among individuals. Due to this, strategies that help some people manage their symptoms and weight may not work for others.

In this article, we investigate whether IBS can cause weight gain or weight loss. We also provide tips for those seeking to lose or gain weight while also managing their IBS symptoms.

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In some cases, doctors may associate weight gain with IBS.

Losing weight or maintaining a moderate weight can also be more difficult for some people with the condition. This may be due to the challenges of exercising frequently and adhering to a restricted diet while avoiding symptoms.

Below, we look at some of the factors that can trigger weight gain for people with IBS.


Evidence suggests that about two-thirds of people with IBS relate their symptoms to certain foods. In many cases, symptom management involves making dietary changes to avoid these foods.

Although IBS trigger foods can vary from person to person, certain fruits, vegetables, and whole grains commonly provoke symptoms. Some people avoid these foods in an effort to prevent uncomfortable IBS symptoms. In doing so, they may opt for foods that are easier to digest and do not create as much waste. These foods may be more calorific, so eating lots of them could lead to weight gain.

Examples of easily digestible, high calorie foods that could trigger weight gain include:

  • refined white bread
  • white rice
  • pasta

Physical activity

Another potential cause of weight gain among people with IBS is a lack of physical activity. People with IBS can experience a sudden, urgent need to use the bathroom, which can lead to stress and worry when leaving the house. This worry may make it tempting to stay in more and be less active.

A 2018 study investigated the effect that IBS has on a person’s quality of life. It found that IBS symptoms can significantly affect a person’s mental health and restrict their activity levels.

Research suggests that depression and anxiety levels are higher in people with IBS. Although depression affects everyone differently, it can lead to changes in a person’s appetite and eating habits, as well as reduce their physical activity. These factors could lead to weight gain.


A 2017 review suggests that some people with IBS may have abnormal endocrine cells in their stomach. These cells secrete hormones that influence appetite and feelings of fullness after eating.

Although more research is necessary to investigate this link further, it is possible that these differences in gut hormones may affect a person’s weight management.

Unlike other gastrointestinal conditions, such as inflammatory bowel disease, IBS does not tend to cause weight loss directly.

However, weight loss may occur if a person is following a restricted diet to manage their symptoms, or if they develop anxiety around food.

Following a restricted diet

Symptom management often involves making dietary changes to avoid known trigger foods. A doctor may recommend a low FODMAP diet to help identify potential triggers and manage symptoms.

FODMAP is an acronym for fermentable oligosaccharides, disaccharides, monosaccharides, and polyols. These short-chain carbohydrates can cause discomfort for people with IBS.

High FODMAP foods that may cause symptoms include:

  • dairy products, such as milk, yogurt, and ice cream
  • wheat-based foods, including bread and cereals
  • some fruits, such as apples, pears, and peaches
  • some vegetables, particularly onions and garlic

As the FODMAP diet is so restrictive, people typically follow it in the short term to help identify trigger foods before slowly reintroducing safe foods.

A person who is following the FODMAP diet may overly restrict their diet and unintentionally consume fewer calories, which could lead to weight loss.

Anxiety around food

A person with IBS may also develop anxiety around food, causing them to consume less food, less frequently. A 2019 study found that the following behaviors were common among people with IBS:

  • limiting food
  • skipping meals
  • following a restrictive diet

The following factors could help a person with IBS lose excess weight.

Moderate exercise

The symptoms of IBS, as well as the worry associated with them, may make it more difficult for a person to exercise regularly. This, in turn, may make it difficult for a person to manage their weight.

It is common for people with IBS to worry about needing quick access to a bathroom, and this may make activities more difficult. However, a person can practice yoga and other forms of exercise at home, where they may feel more comfortable.

A person may wish to try various types of moderate exercise, such as daily walks and swimming. Regular daily exercise should help with weight management. In addition, a 2020 study found that it may also help manage IBS symptoms.

However, some people may find that intense or prolonged exercise triggers their IBS. As such, it can be helpful to consult a medical professional for advice on forms of exercise that may be more comfortable and enjoyable.

Dietary changes

A person with IBS may try to eliminate certain high FODMAP foods from their diet and choose safer foods instead. This approach can lead to weight gain if their chosen foods are high in carbohydrates and fats.

A low FODMAP diet does exclude a range of nutritious foods. However, people can incorporate the following low calorie, low FODMAP fruits and vegetables into their diet to help manage their weight:

  • green beans
  • kale
  • spinach
  • red bell pepper
  • squash
  • carrots
  • cantaloupe
  • grapefruit
  • honeydew
  • blueberries
  • kiwis

Including more protein in the diet may also help with weight management. Proteins tend to be low FODMAP foods that are also filling and can help prevent overeating. Good sources of protein include:

  • unprocessed lean meat
  • fish
  • tofu

If a person is struggling to manage their weight and IBS symptoms, they may wish to speak with a dietitian to create a diet plan that works for them. It can be helpful to keep a food diary to track which foods trigger certain symptoms and to share this information with the dietitian.

A person with IBS may skip meals due to uncomfortable IBS symptoms or as a result of developing a negative association with food.

Eating frequent smaller meals rather than fewer larger meals is one way to maintain adequate calorie intake while lessening the chance of IBS symptoms.

If a person is finding it difficult to consume enough calories, they can fortify their meals with low FODMAP but high calorie ingredients. Examples include:

  • sauces, such as dressings and mayonnaise
  • coconut milk or cream
  • low FODMAP cheese, such as brie and parmesan
  • olive oil
  • starchy vegetables, such as potatoes
  • nuts, such as almonds and walnuts

Some low FODMAP snacks that a person can have between meals include:

  • rice cakes with nut butter
  • coconut yogurt with nuts and seeds
  • smoothies containing blueberries, raspberries, unripe bananas, and low FODMAP sweeteners, such as maple syrup

IBS is a common digestive disorder that can affect a person’s day-to-day life. Some people with the condition may have difficulty managing their weight. This is likely due to the techniques that people use to control their IBS symptoms rather than being a symptom of the condition itself.

People with IBS may gain weight as a result of eating easily digestible but high calorie foods or avoiding or limiting exercise due to physical discomfort or psychological unease. Alternatively, people with IBS may lose weight as a result of eliminating certain foods from their diet or developing anxiety around food.

If a person is finding weight management overly challenging, they may wish to speak with a doctor to rule out other underlying conditions. A doctor can also help a person find a diet or exercise plan that works for them.