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Irritable bowel syndrome (IBS) that predominantly causes diarrhea is known as IBS-D.

If you suffer from IBS-D, then you may experience abdominal cramps, gas, bloating, and frequent diarrhea.

While there is no cure for IBS-D, there are certain foods you can avoid to help you manage this condition. We discuss these foods below. Also, we make specific supplement recommendations at the bottom of this page.

But first, let’s learn how food may be the cause of your symptoms — and what dietary changes you may want to make.

Foods and Drink Triggers

There are a number of foods that can cause diarrhea in IBS or IBS-D. Here are some of the most common:

Insoluble fiber

Insoluble fiber is found in foods such as fruits, vegetables, and whole grains.

Unlike soluble fiber, it passes through your digestive tract without absorbing water. Instead, it bulks up the stool, which allows it to easily and quickly transition through the intestines.

While insoluble fiber may be beneficial for some people, particularly those who suffer from constipation, for people with IBS or IBS-D, insoluble fiber can trigger diarrhea.

Foods to minimize or avoid include:

  • Grains, such as barley and oatmeal
  • Fruits, such as grapefruit, oranges, and berries
  • Root vegetables, such as swedes, parsnips, and carrots
  • Legumes, such as peas, lentils, and chickpeas

Sugar and artificial sweeteners

Foods high in sugar may cause diarrhea in people with IBS or IBS-D. Sugars such as fructose allow water to enter the intestine which can result in loose, watery stools.

Foods that contain sweeteners, such as sorbitol, can also trigger diarrhea because it is poorly absorbed in the small intestine and causes water retention in the gut, once again leading to loose stools.  

Foods to minimize or avoid:

  • Grapes
  • Apple juice
  • Agave
  • Soda
  • Sugar-free chewing gum
  • Stone fruits
  • Dried fruits


Drinks that contain caffeine, such as coffee, tea, and soda, can cause diarrhea in people with IBS or IBS-D.

Caffeine is a stimulant, which means it speeds up the rate at which food moves through your gut. It is also a rectal muscle relaxer — it can prompt a bowel movement soon after consumption.

Although you may tolerate smaller amounts of caffeine well, it’s best to avoid more than one caffeinated drink per day.

Food and drinks to minimize or avoid include:

  • Chocolate
  • Tea
  • Coffee
  • Soda
  • Caffeinated energy drinks

Spicy foods

Seasoning spices are one of the most common causes of diarrhea in IBS and IBS-D — many spices contain capsaicin.

When you eat capsaicin, it stimulates the brain to release endorphins to block the heat sensation. As it passes through the gut, capsaicin can irritate the small intestine, which will cause it to speed up transit. Because this doesn’t allow your colon sufficient time to absorb water, it can cause loose stools.

Foods to minimize or avoid:

  • Chili
  • Jalapeños
  • Cayenne peppers
  • Spicy seasoning and sauces, eg. Sriracha, Cholula sauce

High-fat foods

Fast foods, deep-fried foods, and other foods that contain a lot of saturated fat can cause diarrhea in IBS and IBS-D — they are difficult for the body to digest in large amounts.

Digestive enzymes can be helpful on the occasions when you plan to eat a higher fat meal.

Foods to minimize or avoid:

  • Fast food such as burgers, fries, and hotdogs
  • Deep-fried foods, such as wings, potato chips, and deep-fried vegetables
  • Lard
  • Cream


If you are lactose intolerant, you are one of the 75% of Americans who have problems drinking cow’s milk and eating lactose-containing dairy products. (Lang, 2005)

Lactose intolerance occurs when your body is unable to digest lactose, which is one of the sugars contained in cow’s milk. Symptoms can include gas, bloating, nausea, and loose stool.

Up to 12g of lactose (or one cup of milk) can usually be consumed in one sitting without causing symptoms.

Foods to minimize or avoid:

  • Milk — 1%, 2%, whole, either powdered or fresh
  • Buttermilk
  • Non-cultured yogurt
  • Whey
  • Sour cream
  • Evaporated and condensed milk
  • Cheese spreads
  • Cream
  • Soft cheeses such as brie, camembert, cottage, and mozzarella


Foods high in FODMAPs can be difficult for people with IBS and IBS-D to digest. FODMAPs can cause diarrhea and other symptoms, such as gas and pain.  As with lactose, the dose often determines whether or not you will feel adverse effects from eating these foods.

Foods to minimize avoid:

  • Peaches
  • Onions
  • Dried fruits
  • Fruit concentrate
  • Nuts
  • Wheat and rye
  • Beans
  • Garlic

For detailed guidance, consult the information from Monash University.


Certain types of grains, such as wheat, contain gluten. Gluten is a family of proteins that can cause an allergy or sensitivity.

It can cause serious medical issues for people who have celiac disease.

But even in you do not suffer from this condition, gluten can be a problem. In some people with IBS or IBS-D, it can cause diarrhea.

Is Food Causing your IBS-D?

Food could be the cause of your diarrhea if you suffer from IBS, particularly if you have made recent changes to your diet.

Food may be the cause of your symptoms if you have loose bowel movements after eating certain foods. Keeping a journal of the food you eat, and symptoms you experience can help you figure out which foods are problematic.

Foods to minimize or avoid:

  • Gluten-containing grains are wheat, barley, rye, triticale
  • Many people are also sensitive to oats

Diagnosing IBS-D

IBS-D can be tricky to diagnose. It is often diagnosed using a process of exclusion, whereby your doctor will consider and test for a number of different conditions or causes first and gradually rule them out.

These initial tests may include:

  • X-ray
  • Colonoscopy
  • Endoscopy
  • CT scan

IBS-D Tests

Currently, there are two available tests for IBS-D. The tests are relatively new and have not yet been approved by the FDA.

The tests look for anti-vinculin antibodies and anti-CdtB. These are both characteristics believed to develop in some people who have recently suffered an acute bout of gastroenteritis (stomach flu) caused by common types of bacterium.  

This kind of bacterial overgrowth in the gut may lead to an autoimmune attack on intestinal tissue, causing inflammation and symptoms of IBS, such as diarrhea.

The tests may also help to diagnose or eliminate other causes of diarrhea such as Crohn’s disease, ulcerative colitis, and inflammatory bowel disease (IBD).

If you have IBS or IBS-D and you think your food is causing diarrhea, the best thing to do is try an elimination diet. This involves excluding food you think may be causing diarrhea and then reintroducing them gradually.

Once you can figure out the culprits, you can eliminate them from your diet permanently and alleviate the strain on your digestive system.

Supplement Recommendations

If you and your healthcare provider agree supplements are right for you, we recommend the following:

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Research Citations

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