Spicy foods, those with a high fat content, and some artifical sweeteners can all cause diarrhea. Dairy and gluten may also cause diarrhea in those with intolerances.

Diarrhea is often the result of infection. However, the food a person eats can sometimes cause diarrhea and related symptoms.

This article explores the foods that cause diarrhea, how to tell if diarrhea is due to something that has been eaten, treatment options, and when to see a doctor.

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Some foods are difficult to digest, increase water levels in the bowel, and irritate the digestive system lining. These factors can all cause or worsen diarrhea.

A person may experience diarrhea after eating food due to specific intolerances, such as lactose or gluten intolerance.

Some foodstuffs, and food types, that can cause diarrhea include:

1. Sugar and artificial sweeteners

Some sugars and artificial sweeteners can have a laxative effect.

Fructose is a component of table sugar and occurs naturally in fruits. The body can only digest a certain amount of fructose at one time. Consuming more fructose than the body may cause diarrhea.

One source estimates that approximately 30–40% of people have trouble absorbing significant amounts of fructose.

Some fruits contain more fructose than others. Some examples of foods high in fructose include:

Sugar alcohols, including sorbitol, mannitol, xylitol, and erythritol, are common sweeteners. The body does not absorb these sugar alcohols well, and they can cause diarrhea in some people, especially if consumed in large amounts.

2. Caffeine

Drinks and foods that contain caffeine can cause diarrhea and loose stools in some people. Caffeine is a stimulant and accelerates the rate that food moves through the intestines.

Common dietary sources of caffeine include:

3. High fat foods

Foods that contain a lot of fat can cause digestive difficulties. The body has difficulty breaking down and processing high fat foodstuffs.

Dietary fat also promotes bile production and increases water levels in the small bowel. The combination of these factors can lead to digestive dysfunction and diarrhea.

4. Spicy foods

Spicy foods containing hot peppers are another cause of diarrhea.

Capsaicin is the compound that makes chili peppers taste spicy. It is a potent chemical that can irritate the lining of the stomach and intestines.

Avoiding foods high in capsaicin may help reduce symptoms and frequency of diarrhea.

5. Lactose

People who are lactose intolerant may experience diarrhea after they consume dairy products. Lactose intolerance and malabsorption are common globally. However, it is most prevalent in the Middle East, Southeast Asia, and Sub-Saharan African communities.

Some people with lactose intolerance may tolerate small amounts of dairy products that are aged or lower in lactose. These products include yogurt, kefir, and hard cheeses.

6. FODMAPs

Fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs) are a category of carbohydrates. High-FODMAP foods are difficult for some people to digest and may cause diarrhea.

A 2021 study of irritable bowel syndrome (IBS) patients with diarrhea found that following a low FODMAP diet improved diarrhea symptoms and increased quality of life.

Some categories in this article, such as fructose, lactose, and sugar alcohols, are FODMAPs. The list of high-FODMAP foods is extensive. However, a few other examples include:

A low FODMAP diet can be challenging due to its various food restrictions. If someone thinks that FODMAPs may cause diarrhea, a registered dietitian can provide education and guidance.

Learn all about low FODMAP diets here.

7. Gluten

Gluten is the protein in wheat, rye, and barley. Many people may be gluten intolerant to varying degrees. People with celiac disease have a severe reaction to gluten where their immune system reacts trigger damage to the small intestine. This can cause diarrhea.

People that do not have celiac disease may still have issues tolerating gluten. If someone suspects that gluten may be responsible for their diarrhea, they should contact a doctor for proper testing before starting a gluten-free diet.

Learn more about gluten intolerance here.

The American College of Gastroenterology recommends seeing a doctor if diarrhea continues for longer than 48 hours. People should also see a doctor if diarrhea contains blood, is accompanied by severe stomach pain, or if they do not feel well.

Infants and older adults are more prone to dehydration, which means that diarrhea can be particularly dangerous for people in these groups. It is important to look out for signs of dehydration in these groups, such as:

DIarrhea can be difficult to diagnose in the absence of an underlying cause.

To assess what foods are causing diarrhea, people may find it helpful to keep a food and symptom diary. This may help to identify links between certain foods and diarrhea symptoms.

Before attributing diarrhea to food, it is also important to check recent medication changes. Diarrhea is a common side effect of many drugs, such as antibiotics and medications that contain magnesium.

If someone has diarrhea, they should assess their diet for any potential diarrhea triggers and eliminate them if necessary. This can help to avoid a recurrence of diarrhea.

However, a person can also take steps to treat the immediate symptoms.

Hydration

Diarrhea can cause dehydration. Staying hydrated is crucial when experiencing diarrhea. Besides drinking plenty of water, people can drink the following to maintain hydration.

  • broth
  • caffeine-free tea
  • diluted juice
  • drinks that contain electrolytes, such as sports drinks

Medications

Over-the-counter medications are also available to help treat diarrhea. People should check with their doctor to determine if a store-bought medication is appropriate.

These include:

Probiotics

Probiotics are the beneficial bacteria that live in the gut. They may be helpful in reducing IBS symptoms and preventing diarrhea when taking antibiotics.

Learn all about probiotics here.

Soluble fiber

While foods high in insoluble fiber can worsen diarrhea, foods containing soluble fiber can help promote more formed stools, reducing diarrhea.

Soluble fibers attract water during digestion and form gels. This reduces excess water content in stools. Lentils, barley, and oat bran are high in soluble fiber.

Psyllium is a soluble fiber that is common in many fiber supplements.

Learn more about psyllium and fiber supplements here.

Oily, high fat foods, spicy chili peppers, and artificial sweeteners can all disrupt the digestive system and cause diarrhea. In people with intolerances, gluten and lactose may also cause diarrhea.

Keeping a food and symptom diary can help people to assess what foods are causing their diarrhea. They can then reduce the intake of these foods or eliminate them from their diet entirely.

There are many home remedies and over-the-counter medications that can reduce symptoms. If a person has diarrhea for 2 days or more, has blood in their stool, or feels severe stomach pain, they should contact a doctor immediately.