How Long Do FODMAPs Take to Trigger IBS Symptoms?

For people with irritable bowel syndrome (IBS), meals can lead to uncomfortable IBS symptoms. They may leave you running to the bathroom shortly after you have finished eating. This can be a frustrating reality.

FODMAPs – and how the body breaks them down – may be part of the problem. The more you understand about FODMAPs, the more you may be able to avoid triggering IBS episodes.¹

What are FODMAPs?

FODMAPs are short-chain carbohydrates that are not absorbed very well in the gut (the small and large intestines). FODMAP stands for fermentable oligosaccharides, disaccharides, monosaccharides, and polyols.¹

FODMAPs are found in a variety of foods, including:^1,2

• Fruits – apples, peaches, and dried fruit
• Vegetables – asparagus, garlic, and onions
• Nuts and legumes – cashews, pistachios, and beans
• Grains – wheat, barley, and rye
• Dairy products – milk, yogurt, and soft cheeses

What symptoms do FODMAPs cause in people with IBS?

FODMAPs are naturally found in many healthy foods. Many people have no digestion issues when eating FODMAPs. But for those with IBS, eating these foods can lead to uncomfortable symptoms like:¹

• Gas
• Bloating
• Stomach cramping
• Stomach pain
• Diarrhea
• Constipation

How and why FODMAPs trigger IBS symptoms

FODMAPs move slowly through the digestive system. Along the way, 2 processes occur that may trigger symptoms in people with IBS.^1,2

In the small intestine, certain FODMAPs attract and draw water into the bowel. This can affect how fast the bowel moves and can cause diarrhea.^1,2

When FODMAPs reach the large intestine, gut bacteria work to break down, or ferment, the food in order to use it as fuel. This fermentation produces gas and bubbles, which can result in bloating and gas.^1,2

How long does it take for FODMAPs to trigger symptoms?

Symptoms after eating high-FODMAP foods vary from person to person. Generally, symptoms may begin within a few hours after eating. For some people, the response may be more immediate, occurring within 30 minutes to 2 hours. For others, it might take longer. This can be due to:³

• Differences in each person’s digestive system
• How sensitive a person is to the FODMAPs consumed
• The amount of FODMAPs consumed

It may not be the most recent meal that is causing IBS symptoms. The digestive system typically takes many hours to several days to fully digest food after it is eaten. So, there is always some food moving through the digestive tract. IBS symptoms may be caused from a previous meal eaten several hours before. This delayed response can be tricky when trying to understand which foods are triggering symptoms.³

How long do symptoms last?

How long IBS symptoms last after consuming FODMAPs also varies. Symptoms may last several hours and go away within a day. But some people might have symptoms for a longer period. Symptoms may last longer if you consume a large amount of FODMAPs or if you have a very sensitive digestive system.³

Consider a low FODMAP diet

Managing IBS symptoms often involves trying a low FODMAP diet. This means identifying and avoiding high FODMAP foods that trigger symptoms. Then, you can slowly reintroduce those foods to find out your tolerance level.^1,2,4

Working with a dietitian can be a huge help. Dietitians can help you develop an eating plan and gradually reintroduce FODMAPs to learn how much of a specific food you can tolerate before symptoms occur. This will be different for everyone, so it is important to take a personalized approach.²

A low FODMAP diet may not work for everyone with IBS. And the diet is not a cure-all. But cutting out foods that trigger symptoms may help reduce those symptoms quite a bit. It is important to reintroduce all possible foods into your diet to make sure you get enough essential nutrients.^1,2,4

Understanding the relationship between FODMAPs and IBS can empower you to manage your symptoms more effectively. By recognizing which foods are high in FODMAPs and how they impact the digestive system, you can make informed choices to improve your quality of life.