IBS and Weight Gain or Loss

What Is Irritable Bowel Syndrome?

Irritable bowel syndrome (IBS) is a condition that causes a person to experience uncomfortable gastrointestinal (GI) symptoms on a regular basis. These include:

  • stomach cramping
  • pain
  • diarrhea
  • constipation
  • gas

The difference between IBS and other conditions that cause similar symptoms — such as ulcerative colitis and Crohn’s disease — is that IBS doesn’t damage the large intestine.

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Symptoms for the condition can range from mild to severe. Because they impact a person’s digestive capabilities, the condition can also result in weight loss or gain. However, there are steps you can take to maintain a healthy weight and live well with IBS.


IBS and Weight

How Does IBS Impact Your Weight?

According to the , IBS is one of the most common disorders that affect the functioning of the GI system. As much as of adults in the United States have reported symptoms that are synonymous with IBS.

The exact causes of IBS are unknown, but there are a few physical and psychological causes that are known to worsen symptoms. For example, some people with IBS experience increased bouts of diarrhea because their intestines seem to move food through faster than normally. In others, their IBS symptoms are associated with constipation due to a gut that moves more slowly than normal.

IBS doesn’t affect every person’s weight, but it can result in weight loss or gain in some people. For example, some people may experience significant abdominal cramping and pain that may cause them to eat fewer calories than they normally would. Rapid stomach emptying that causes a person to experience significant diarrhea could also impact a person’s ability to absorb key nutrients, leading to weight loss.

In some instances, IBS can lead to weight gain. This is because on days you feel better, you may try to eat to compensate for missed calories. Some people also choose a lower residue diet that tends to be higher in calories in an attempt to avoid uncomfortable symptoms.

You may not always be able to control your symptoms when you have IBS, but there are some ways you can maintain a healthy weight and eat a healthy diet that includes fiber.


Diet Recommendations

IBS and Diet

A diet that involves eating several small meals is recommended over eating large meals when you have IBS. In addition to this rule of thumb, a diet low in fat and high in whole grain carbohydrates can also benefit you when you have IBS.

Many IBS sufferers are hesitant to eat foods that have fiber for fear they’ll cause gas that worsens symptoms. You don’t have to avoid fiber. However, you should slowly add fiber to your diet, which can reduce the likelihood you’ll have gas and bloating. Aim to add between per day and drink plenty of water along with the added fiber to minimize symptoms. An ideal amount of fiber for adults is between per day.

You should also avoid foods that are known to worsen IBS — that also tend to result in weight gain. These include:

  • alcoholic beverages
  • caffeinated beverages
  • drinks with significant amounts of artificial sweeteners
  • foods known to cause gas, such as beans and cabbages
  • high-fat foods
  • whole milk products

Your doctor may also recommend keeping a journal of foods you eat to see if you can identify foods that tend to worsen your symptoms.



The FODMAP Diet for IBS

Another option for those looking to maintain a healthy weight and minimize IBS symptoms is the FODMAP diet. FODMAP stands for fermentable oligo-di-monosaccharides and polyols. These are sugars found in foods that tend to worsen symptoms in people with IBS.

The diet involves limiting foods that are high in FODMAPs, including:

  • fructans
  • fructose
  • galactans
  • lactose
  • polyols

Reading food labels carefully and avoiding these additives can help you reduce the likelihood that you’ll experience stomach symptoms related to IBS.

Examples of FODMAP-friendly foods that can reduce IBS symptoms include:

  • fruits, including bananas, blueberries, grapes, oranges, pineapples, and strawberries
  • lactose-free dairy
  • meats, including chicken, eggs, fish, pork, and turkey
  • vegetables, including carrots, cucumbers, green beans, lettuce, kale, potatoes, squash, and tomatoes

Those on a FODMAP diet may eliminate some foods and slowly add them back in to determine what foods can be safely eaten.




Weight loss or gain can be a side effect of IBS. However, there are diet approaches that can help you reduce your symptoms while maintaining a healthy weight. If a dietary approach doesn’t help your symptoms, talk to your doctor about other potential causes of your weight loss or gain.

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