What Causes Chronic Diarrhea After Eating?

Reasons You Might Be Having Postprandial Diarrhea Frequently

Woman holding her stomach in pain
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Diarrhea is never pleasant, and when it frequently happens right after eating, it becomes hard to enjoy a meal. You may become wary of what to eat and anxious about eating anything at all. Learn about some of the more common causes of chronic diarrhea. This information will help you to better understand what might be going on so that you can work with your doctor on an effective treatment plan.

Any new or ongoing digestive symptom should be brought to the attention of your doctor so that you obtain an accurate diagnosis and treatment plan.

Although chronic diarrhea after eating may be the result of one of the health conditions on this page, it can also be a sign of other serious diseases.

Note: If your diarrhea after eating is a brand-new and severe problem, please see this article: acute causes of diarrhea after eating.

Causes of Chronic Diarrhea After Eating

Diarrhea after a meal is known formally as postprandial diarrhea. There are a wide variety of health problems that have chronic diarrhea as a symptom.  If you have one of these disorders, the simple act of eating a meal may serve as a trigger for diarrhea episodes.

As you can see, the reasons behind the symptom of diarrhea can vary widely depending on your diagnosis. Addressing the underlying illness can help to bring about relief from the symptom of running to the bathroom after meals.

Irritable bowel syndrome (IBS): Just the simple act of eating can be enough to set off the symptom of diarrhea in some people who have IBS.

It is not clearly known why there is such a hyperreactivity of the digestive system in this disorder.

Bile acid diarrhea (BAD): Researchers are starting to find evidence that some people who are diagnosed with IBS actually have BAD. Bile acids are secreted by your gallbladder in order for your digestive system to digest fats.

When these acids are not re-absorbed properly they serve to stimulate contractions in your large intestine, resulting in diarrhea. Sometimes the cause of BAD is unknown, other times it occurs following surgery or illness involving your digestive organs (your gallbladder, pancreas or your small intestine, for example). 

Gallbladder removal: Without a gallbladder, some people experience a problem with poor regulation of bile acids into the small and large intestines, causing similar symptoms as BAD. Although for most people, this symptom resolves itself quickly after the surgery date, for others it remains an ongoing problem.

Lactose intolerance: People who have lactose intolerance lack sufficient amounts of the enzyme necessary to break down lactose, a sugar found in milk and milk products. This can cause the symptom of diarrhea after consuming dairy foods. Lactose intolerance can be identified through the use of a breath test or an elimination diet.

Sugar malabsorption: In addition to lactose, some people are unable to digest the sugars fructose and sorbitol. Fructose is found in many fruits and high fructose corn syrup. Sorbitol is also found in some fruits as well as artificial sweeteners.

Like lactose intolerance, fructose or sorbitol malabsorption can be identified through the use of breath testing or an elimination diet.

Celiac disease: People who have celiac disease experience an autoimmune reaction in response to ingesting gluten, a protein found in wheat, rye, and barley. Diarrhea from celiac disease is often odorous, and stool may be more likely to float rather than sink. Celiac disease has serious health consequences, so if you are experiencing chronic diarrhea after eating, you should speak with your doctor about being screened for the disease.

Inflammatory bowel disease (IBD): The two forms of IBD—Crohn's disease and ulcerative colitis—can both cause the symptom of diarrhea after eating.

Unlike any of the above health problems, the diarrhea of IBD may include signs of blood in the stool. Any sign of blood in the stool needs to be immediately brought to the attention of your doctor.

Dumping syndrome: This syndrome is most commonly experienced by people who have undergone bariatric surgery for weight loss. Dumping syndrome is also known as rapid gastric emptying ​because the contents of the stomach empty too quickly into the small intestine. Therefore, eating, particularly meals with a high sugar content, can trigger off symptoms such as diarrhea.

Microscopic colitis: This type of colitis is a distinctly different illness than ulcerative colitis. With microscopic colitis, inflammation in the cells lining the intestines can only be seen when tissue is looked at under a microscope. The cause of microscopic colitis is not well known. Its symptoms include persistent or intermittent episodes of watery diarrhea.

Colon cancer: Chronic diarrhea is not typically a sign of colon cancer (constipation may be more likely), however any change in the frequency of bowel movements has been associated with the presence of cancer. Other symptoms of colon cancer include blood in or on the stool, fatigue, anemia, and unexplained weight loss. If you have any of these symptoms alongside chronic diarrhea, you need to see your doctor immediately.

What to Do for Chronic Problems with Diarrhea After Eating

  1. Tell your doctor. Any unusual symptom should always be brought to the attention of your doctor. This helps to ensure that you receive a proper diagnosis and therefore a helpful treatment plan can be developed. 
  2. Follow your doctor's orders to best manage your underlying health problem.
  3. Eat small meals throughout your day and avoid fatty foods, such as fried food, fatty meats, and thick gravy. Large meals and fatty foods can increase the strength of intestinal contractions and thus prompt a diarrhea episode.
  4. Use relaxation exercises to calm your body. Due to the close connection between your brain and your gut, stress can be a trigger for diarrhea. Most of us deal with a lot of stress in our lives, not to mention the fact that having diarrhea after your meals is stressful! Both deep breathing exercises and progressive muscle relaxation skills can be effective in calming your body and therefore offer the potential for slowing down the emptying of your bowels.


DiBaise JK, Islam RS "Bile Acids: An Underrecognized and Underappreciated Cause of Chronic Diarrhea" Practical Gastroenterology 2012 36(10):32-44

"Diarrhea" Medline Plus.  https://medlineplus.gov/diarrhea.html .

"Diarrhea" National Digestive Diseases Information Clearinghouse (NDDIC) https://www.niddk.nih.gov/health-information/digestive-diseases/diarrhea/symptoms-causes

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