What should you not eat for IBS?

Irritable bowel syndrome (IBS) causes abdominal symptoms, including diarrhea, constipation, bloating, and cramps. Research suggests that avoiding certain foods may significantly improve symptoms.

Experts do not know exactly why IBS happens. Factors that may play a role include genetic and inherited features, hypersensitivity, gut microbiota, low grade inflammation, a history of gastrointestinal infection, and hormonal changes that affect the nervous system. The exact cause may depend on the individual.

For this reason, no single diet will suit everyone with IBS, but some foods are commonly linked with a worsening of symptoms.

Research indicates that consuming high-FODMAP foods may worsen symptoms of IBS, such as:

However, some people with IBS can tolerate certain quantities of FODMAP-containing foods.

The MONASH University FODMAP app is a helpful database of foods that lists their FODMAP level based on serving sizes. For example, it considers a 2.8-ounce (oz) serving of avocado as high in FODMAPs and a 1-oz serving as low in FODMAPs.

This is because foods can be high or low in FODMAPs based on serving sizes.

A doctor or dietitian can help a person make dietary changes aimed at resolving IBS symptoms.

To identify triggers, they may recommend eliminating certain foods, then reintroducing them one by one to determine which ones cause symptoms. They may also ask a person to keep a food journal to note down when symptoms occur.

Although most people with IBS have different food triggers, some food groups or products are more likely to cause IBS symptoms than others.

The following can trigger symptoms of IBS:

1. Fruits

Fruits, such as whole apples, rhubarb, and kiwis, can have a laxative effect, as they contain fiber and increase water content in the digestive tract. They might help people who are experiencing constipation but not those with diarrhea.

The following fruits contain FODMAPs, and may worsen symptoms:

Fruits in the following forms may be high in FODMAPs:

Low FODMAP fruits that may be suitable for people with IBS include canteloupe, oranges, and guava.

2. Vegetables

As with fruits, vegetables add fiber to the diet, and some draw water into the intestines. This can trigger diarrhea. but those with constipation may find them helpful.

Vegetables that are high in FODMAPs include:

3. Legumes and pulses

Pulses contain fiber and are high FODMAP foods.

They include:

Pulses are a crucial source of protein for many people, and avoiding them may be difficult. Some experts suggest consuming them in small amounts or using cooking methods that reduce the risk of pulses triggering symptoms.

For example, when cooking pulses, discarding the water before serving helps reduce the galactooligosaccharide (GOS) content.

4. Dairy products

The lactose in dairy products can make them high in FODMAPs.

5. Whole wheat and rye products

Some breads have high FODMAP content because of the grains they use. They may not be helpful for people with IBS.

Foods containing the following grains may not be helpful for people with IBS:

Rye and whole-wheat bread have high levels of fructans. This makes them high-FODMAP foods. Similar flours are also used in some sauces.

Small amounts of bread made with refined wheat flour are considered low FODMAP. However, if a person eats more than one slice, it will be high FODMAP.

6. Sweeteners

Sugars and sweeteners may trigger symptoms, for example:

7. Ultra-processed foods

Highly processed foods often contain high levels of sugar, fat, and other substances that may trigger IBS in some people. Some experts believe there is a link between ultra-processed foods and IBS.

Some of ultra-processed foods are:

8. Alcohol

Foods and drinks containing alcohol may trigger IBS symptoms, and some research suggests high alcohol consumption may increase the risk of developing IBS.

However, other experts say findings are unclear, and the effect may depend on how a person consumes alcohol and what type of IBS symptoms they have.

9. Caffeine

Caffeine can boost motility, the movement of food through the gut. Reducing caffeine intake may help manage diarrhea related to IBS.

10. Fried foods

In one older study from 2013, 52% of people with IBS said they had symptoms after eating fried or fatty foods. However, there is not enough scientific evidence to confirm this.

11. Spicy foods

Hot or spicy foods may irritate the digestive system and trigger IBS symptoms.

Some flavorings — such as miso, soy sauce, and saki — contain ingredients that might act as FODMAPs in large quantities.

More research is needed to confirm a link between IBS and spicy foods.

12. Gluten

Some research suggests people with IBS may have a higher chance of being sensitive to gluten. Gluten sensitivity differs from celiac disease — in celiac disease, gluten causes actual damage to the intestines.

13. High sugar foods

Added and refined sugar may trigger or worsen low grade inflammation and gut permeability. For this reason, it may contribute to IBS symptoms.

Added sugar is present in many products, for instance:

However, foods and drinks that trigger IBS symptoms vary between individuals. A person with IBS will need to identify their individual triggers.

The following foods and food types may be suitable for people with IBS. However, it depends on the portion size.

While it may not be possible to eliminate all the IBS triggers in a recipe, reducing their quantities can help.

Tips for eating out

When going to a restaurant, the following strategies can help.

First, be sure to read the menu carefully. Check for ingredients that may cause symptoms and ask:

Some people prefer to check the menu online and inquire ahead of time.

Here are some other tips

Many people with IBS find that cooking food at home with fresh ingredients is a good way to avoid symptoms.

Other tips that may help include:

IBS affects people differently, but a nutritious eating plan tailored to an individual’s specific needs can help.

Here are some questions people often ask about foods to eat and avoid with IBS.

Which foods can trigger IBS?

This depends on the individual, but some people find that ultra-processed foods, fried foods, pulses, hot and spicy dishes, dairy products, sweeteners ending in “-ol”, and certain fruits and vegetables can trigger symptoms. It is best to work with a doctor or dietitian to identify triggers and make a plan around the results.

What foods should I eat during an IBS flare?

Opt for foods that are easy to digest, such as low FODMAP fruits and vegetables. Cantaloupe and cucumber are low FODMAP options. Try eating porridge oats regularly. One source recommends consuming up to 1 tablespoon of linseeds (flaxseed) per day. Linseed and porridge contain soluble fiber. Drink plenty of water to help prevent both constipation and dehydration in the case of diarrhea.

What can calm an IBS flare?

Opt for foods that do not worsen symptoms, and ask a doctor about medication to manage symptoms. Over-the-counter drugs, such as loperamide (Imodium), can reduce diarrhea. Stool softeners, such as Normacol, can help with constipation.

IBS is a common gastrointestinal disorder that can cause significant discomfort. A person’s diet can trigger or worsen symptoms.

Identifying and avoiding triggering foods and drinks can help people with IBS enjoy their meals at home or eating out.