Diets for Irritable Bowel Syndrome

The best eating plan for you will depend on your symptoms

One of the most challenging aspects of having irritable bowel syndrome (IBS) is knowing what to eat so as not to set off symptoms. It's not helpful that, because no two bodies are the same, there is no one-size-fits-all IBS diet. An effective eating plan for diarrhea-predominant irritable bowel syndrome (IBS-D) may not be helpful for someone who has IBS with constipation.

That said, there are several options to choose from, including guidance for specific sub-types of IBS. What's more, health care providers have a comprehensive understanding of all aspects of the relationship between food and IBS. If you have IBS, this knowledge can help you to make the best food choices for you.

Top Specialized Diets for IBS

In 2014, the American College of Gastroenterology published a thorough review of various eating plans that had been studied for their effectiveness in preventing and easing symptoms of irritable bowel syndrome. Of dozens of diets the researchers looked at, only two were found to be significantly effective: the low-FODMAP diet and the gluten-free diet.

The Low-FODMAP Diet

The acronym FODMAP stands for "fermentable oligo-, di-, monosaccharides, and polyols"—a collection of short-chain carbohydrates found in many common foods. Eating foods high in FODMAPs results in increased volumes of liquid and gas in the small and large intestine that can contribute to flatulence, bloating, and abdominal pain. and bloating. Given these are all hallmarks of IBS, it makes sense that eliminating foods high in FODMAPs would help to prevent and/or ease these symptoms.

The diet can be challenging as many common foods are high in FODMAPS.

The Five Types of FODMAPS

  • Fructans (found in wheat, onions, garlic, and certain food additives)
  • Fructose (present in many fruits, honey, and high fructose corn syrup)
  • GOS (galactooligosaccharides in legumes such as beans, chickpeas, and lentils)
  • Lactose (the sugar component of milk and other dairy foods)
  • Polyols (sugar alcohols in blackberries, cauliflower, and mushrooms, for example)

The low FODMAP diet involves two phases:

  1. Phase 1: Restrict foods that are high in FODMAPs for a short period of time.
  2. Phase 2: Introduce these foods back into your diet, one FODMAP type at a time, to assess your own tolerance for each. Following this structure ultimately will allow you to eat as wide a variety of foods as possible while at the same time preventing symptoms.

Research has shown that approximately 75 percent of people with IBS who attempt a low FODMAP diet under the supervision of a dietitian experience significant symptom relief.

The Gluten-free Diet

Many people who have IBS report their symptoms improve when they eliminate gluten from their diet, even if they do not have celiac disease. Gluten is a protein found in foods that contain wheat, rye, or barley.

The notion gluten may play a role in IBS has received preliminary research attention. Some scientists theorize that for a subset of people with IBS, a condition called non-celiac gluten sensitivity may cause symptoms.

Other researchers argue that gluten is not the problem, but rather the FODMAP fructan that is also found in wheat, rye or barley. If you're interested in trying a gluten-free diet, start by consulting with your doctor, who may want to test you for celiac disease first.

Food Allergies, Intolerance, and Sensitivities

For people with IBS who also have an allergy, intolerance, or sensitivity to a particular food or foods, identifying and following a diet that excludes those foods may be helpful in preventing IBS symptoms.

If you're uncertain what these conditions are, here's a quick guide:

Food Allergy. A food allergy exists when the body has an immune system response to a food that's harmless for most people. Although an allergy to a specific food typically brings on classic allergy symptoms (itching, hives, breathing difficulties, lip swelling, and throat tightening), it also may trigger digestive abdominal pain, nausea, vomiting, or diarrhea. Symptoms typically show up within two hours of eating the triggering food.

Food Intolerance. An intolerance to a specific type of food is defined as when the body isn't able to fully digest and absorb it. A familiar example is lactose intolerance, in which there's too little lactase (an enzyme) to break down lactose, the milk sugar in dairy products, leaving the sugar available to be acted upon by gut bacteria and causing digestive symptoms.

Another example is fructose malabsorption, which affects approximately a third of the population due to a deficit in a certain transporter substance necessary for fully digesting any fructose you might have eaten.

Food Sensitivity. Food sensitivities are less easy to define, but there are a variety of different foods associated with triggering IBS symptoms. Again, one of those is gluten. Other common foods identified as IBS trigger foods include chocolate, coffee, corn, soy, and meats.

What to Eat for Gas and Bloating

Avoiding foods known to cause gas and bloating is an obvious part of an IBS diet. Besides what you eat, how you eat can help to prevent these symptoms. Eating more slowly, for example, may help reduce the amount of air you swallow with each bite. (The same can be said for not chewing gum, by the way.)

For a more comprehensive approach, at the very least you will want to identify whether lactose intolerance or fructose malabsorption are causing your symptoms. You may want to consider trying the low-FODMAP diet, as it can be effective in reducing the symptoms of gas and bloating.

Last, you may want to talk to your doctor to rule out small intestinal bacterial overgrowth (SIBO), a health condition that can present with gas and bloating and other IBS symptoms.

What to Eat for Constipation

To ease chronic problems with constipation, most likely you need to be eating more fiber. However, it is very important to increase the amount of fiber that you take in slowly to give your body time to adjust. The type of fiber that you add is also important, as researchers have found that soluble fiber is better tolerated and more helpful for people who have IBS.

In addition to adding more fiber, you can help to ease chronic problems with constipation by drinking more water and eating foods that contain healthy fats. You may also find it helpful to make sure that you eat a large breakfast so as to work with your body's biorhythms to encourage a morning bowel movement and to eat your meals throughout the day on a predictable schedule so as to keep things moving.

What to Eat for IBS with Diarrhea

If you're plagued by the urgency and disruptive nature of diarrhea, sticking with bland foods may be your go-to for really bad days, but this strategy may not serve as a long-term solution. For best results, you will want to rule out any food intolerance or SIBO and perhaps give the low-FODMAP diet a try.

Other ways to help your digestive system to settle down include avoiding large meals and instead choosing to eat small meals throughout the day. Avoid foods that are fatty, greasy, or creamy, as those can speed up intestinal contractions and send you running to the bathroom.

Recipes for IBS

Home-cooking has health advantages in general but can really make a difference in how you feel when you have IBS, as you have full control over the ingredients that you are using. The advent of the low-FODMAP diet has inspired multiple food bloggers to post their favorite low-FODMAP recipes. You now have more options than ever before for cooking IBS-friendly meals for yourself that can also be shared with family and friends.

A Word From Verywell

The relationship between food and IBS is a complex one, but there are changes you can make in both how you approach meals and the foods that you choose to eat. A smart eating strategy can dovetail nicely with the medical treatment you receive from your doctor in order to bring about symptom relief.

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