IBS and Weight Loss: Can IBS Make You Lose Weight?

IBS and Weight loss

Weight loss is not one of the main symptoms of IBS (irritable bowel syndrome). In fact, when a person starts losing weight, the diagnosis of IBS becomes questionable.

However, IBS can result in alternating weight gain and weight loss. Although these weight changes are not significant and may also be controlled by the patient.

Some of the common reasons that a person with IBS may be losing weight are:

  • Abnormal diet
  • Anxiety
  • Medications

What is IBS (Irritable Bowel Syndrome):

IBS is a disorder of GIT in which one suffers from abdominal bloating, pain, gas, constipation, diarrhea, cramps in the stomach, etc.

IBS or irritable bowel syndrome, as the name suggests, is an irritable response of the gut to meals.

People with IBS can have diarrhea alternating with constipation, predominant diarrhea (IBS-D), or predominant constipation (IBS-C).

Crampy abdominal pain, bloating, flatulence, and dyspepsia are other common symptoms of IBS. About 60% of the patients with IBS have concomitant symptoms of anxiety.

In fact, IBS is considered one of the physical manifestations of anxiety. This is also true as most patients with IBS respond to medications that are used to treat anxiety.

Common and uncommon symptoms of IBS include:

Common symptoms

Less common symptoms

  • Abdominal pain and cramping.
  • Diarrhea.
  • Constipation.
  • Bloating.
  • Flatulence.
  • Lethargy.
  • Heat burns.
  • Unexplained weight loss
  • Palpitations
  • Insomnia

IBS or No IBS?

Around 25 to 45 million people in the United States have symptoms of IBS. More than half of them are females.

Some people think that IBS is frequently overdiagnosed. People with functional dyspepsia, GERD, IBD (inflammatory bowel disease), SIBO (small intestinal bacterial overgrowth), chronic intestinal infections like giardiasis, HIV enteropathy, and even intestinal cancers can have symptoms that may mimic the symptoms of IBS.

IBS is therefore a diagnosis of exclusion. When all the above-mentioned diseases have been excluded by proper investigations, the person may only then be labeled to have IBS.

Some of the symptoms which indicated diseases other than IBS include:

  • Anemia
  • Fever
  • Blood in stools
  • Persistent vomiting
  • Significant weight loss
  • Lumps in the body
  • Fluid in the peritoneal cavity (fluid in the abdomen)
  • Jaundice
  • Abnormal investigations such as raised inflammatory markers, ESR (sedimentation rate), CRP, Endoscopy, Colonoscopy, and Imaging studies (Ultrasound and CT of the abdomen).

IBS, Weight Loss, and Diet:

IBS is a functional disorder. It does not actually affect the intestine anatomy. Thus, the absorptive surfaces and the villi in the intestines are normal.

So, IBS is not usually associated with weight loss as seen in other conditions of the intestines like IBDs, infections, and cancers of the intestines.

However, it causes fluctuations in weight because it affects one’s choice of what to eat. Due to IBS, you naturally avoid many types of foods which could increase your condition of IBS, and this could result in changes in your body weight.

In addition, some healthy food items may worsen the symptoms of IBS. These include milk and dairy products, gluten, meat, and fried foods. People tend to avoid these food items resulting in weight loss.

Many IBS symptoms such as gases, diarrhea, abdominal bloating, pain, cramps, etc may affect the individual’s tendency to eat.

IBS, Weight Loss, and Diarrhea:

IBS can directly affect weight as it may cause diarrhea which results in loss of weight. Diarrhea results in loss of body weight as essential nutrients along with water are lost from the body.

IBS-D is one of the main types of IBS. This is a type of IBS where people tend to have predominant symptoms of diarrhea. Hyperdefecation or passing semi-digested stools are more common than true diarrheal stools.

This can result in some degree of weight loss. In some people, IBS results in diarrhea because food moves faster than normal through their Gastrointestinal tract.

While in others food moves slowly through GIT which results in constipation. So there are no fixed symptoms of IBS for everyone.

IBS, Weight Loss, and Workout

The individual suffering from IBS may not be able to do exercise mostly due to severe symptoms such as cramps, pain, diarrhea, etc.

These symptoms may affect the tendency of an individual to exercise and do a proper workout which he could have otherwise done in healthy conditions. The lack of exercise may lead to a change in weight.

Although lack of exercise is associated with weight gain. However, patients who are not doing workouts lose muscle mass and develop abnormally huge bellies.

Patients may observe weight gain but the weight gain is not healthy weight gain. This adds to the symptoms of anxiety which is more common in patients with IBS.

IBS Bloating:

The individual suffering from IBS may have abdominal bloating and gases. Such an individual may confuse himself with being overweight and heavy and so he might stop eating due to being over-conscious. This results in weight loss.

IBS and Stress:

If an individual’s weight seems to be increasing due to symptoms of IBS such as bloating, he/she might stop eating certain foods due to stress.

This could lead to a sudden decrease in their weight and result in weight loss. Anxiety alone is also a major cause of weight reduction.

Adrenaline is a stress hormone that has strong anorexiant properties. It increases the metabolic rate of our body and results in the burning of calories even during states of rest and sleep.

IBS Medications and Weight Loss:

Certain IBS medications are associated with weight loss. Although these medications are not associated with significant weight loss, they could add to the problem.

The table below shows the common IBS medications and their effect on body weight:

IBS Medications

Weight Loss

Weight Neutral

Weight Gain

Linaclotide (Linzess)­✔✔?
Amitiza (Lubiprostone)✔✔?
Librax (Chlordiazepoxide + Clidinium)?
Rifaximin (Xifaxin)✔✔?
Viberzi (Eluxadoline)??
Tegaserod (Zelnorm)✔✔?
Plecanatide (Trulance)??
Tenapanor (IBSrela)?

As shown in the table above, weight loss is common with Linzess, Amitiza, Rifaximin, Tegaserod, and Tenapanor.

Although data about IBS medications and associated weight gain or weight loss is limited, some medicines used to treat IBS are more likely to cause weight loss than others.

The table below shows the weight loss effects of different IBS medicines:

Weight Loss

Weight Neutral

Weight Gain

  • Linaclotide (Linzess)
  • Amitiza (Lubiprostone)
  • Rifaximin (Xifaxin)
  • Tegaserod (Zelnorm)
  • Tenapanor (IBSrela)
  •  Librax (Chlordiazepoxide + Clidinium)
  • Viberzi (Eluxadoline)
  • Plecanatide (Trulance)
  • Alosetron


If you are suffering from IBS, you might make the mistake of following a severe diet or restricting yourself completely from eating.

This could deprive you of many essential nutrients and minerals necessary for your body. The best strategy is to eat such foods which not only prevent your IBS symptoms to flare up but also have essential nutrients and vitamins.

  • Seeds
  • Nuts
  • Low-FODMAP fruits, like blueberries, bananas, strawberries, etc
  • Green smoothies
  • Coconut oil
  • Olive oil
  • Avocados
  • Avocado oil

So don’t skip meals or don’t restrict your diet. Instead, try to add an extra meal daily to your routine so that you can maintain your healthy weight.

What do you think?

Written by Dr. Ahmed

I am Dr. Ahmed (MBBS; FCPS Medicine), an Internist and a practicing physician. I am in the medical field for over fifteen years working in one of the busiest hospitals and writing medical posts for over 5 years.

I love my family, my profession, my blog, nature, hiking, and simple life. Read more about me, my family, and my qualifications

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