Danielle Lewis
Danielle LewisRegistered Dietitian

Accidentally Eating a High FODMAP Food: What Symptoms to Expect and What to Do

Published on December 5, 2021

Despite your best efforts, FODMAPs may unintentionally sneak into your diet. If you accidentally eat a high FODMAP food or a high FODMAP serving size of a food, you may find yourself sitting there all day wondering if and when your pesky GI symptoms are going to show up. What is the typical timing of these reactions? And what are FODMAP-specific reactions? This guide will show you what to expect, when to expect it, and how to manage it.

What to Expect After Eating a High FODMAP Food

As outlined in a previous blog post, FODMAPs are certain types of carbohydrates found in foods. When we eat foods that contain FODMAPs (or high FODMAP foods), they start fermenting in the GI tract. This fermentation process causes gas production, abdominal bloating, and discomfort. This fermentation process is a normal part of digestion. However everyone’s GI tract is different, so the way that your body responds to FODMAPs may be more or less sensitive than others.

FODMAPs also have an osmotic effect on the GI tract which means that they attract water. This can cause diarrhea, cramping, and bloating. 

So, based on the fermentation process of FODMAPs and the osmotic effect of FODMAPs, if your GI tract is sensitive to FODMAP foods, you can expect to feel any of the following after ingesting a high FODMAP food: abdominal pain, bloating, excess gas, gastrointestinal gurgling, diarrhea, and/or constipation.

Please note that FODMAP reactions do NOT include: bloody stools, black/tarry stools, fever, or vomiting. If you have any of these symptoms, it is recommended to discuss this with your GI provider, as these can be signs of more serious conditions that warrant further testing.

Timing of FODMAP Reactions

Immediate Reactions

We know that FODMAPs react in the small and large intestine. That means that a FODMAP reaction will typically occur 2-8 hours after eating or drinking a high FODMAP food. 

Delayed Reactions

However, symptoms can still occur up to 48-72 hours after FODMAP consumption. This is because the high FODMAP food may still be sitting in your intestine. Other foods that you eat help push the FODMAP-containing food through your GI tract, which can cause delayed symptoms. This is known as gastrocolic reflex and may also explain why some people experience GI symptoms immediately after eating. If you are one of these people, it doesn’t necessarily mean that you are reacting to the food you just ate. It is likely related to previously consumed FODMAPs moving through your GI tract. Keeping a food and symptom journal to review with a low FODMAP-trained dietitian can help you pinpoint which foods are actually triggering your symptoms. The Fig app can help you avoid high FODMAP ingredients.

Non-FODMAP Reactions

There are other reasons why you may experience GI symptoms immediately after eating. Some of these include: food allergies (remember that FODMAPs are not allergies, they are intolerances), functional dyspepsia, or accelerated gastrocolic reflex. Explore these further with a physician and registered dietitian.

How to Manage FODMAP Reactions

If you do experience symptoms after eating a high FODMAP food, you can try the following to help calm your symptoms:

  1. Peppermint. Peppermint tea, oil, or capsules can help with bloating and discomfort that is associated with abdominal bloating. 
  2. Heating pad. This can help loosen your abdominal muscles, which can ease pain and bloating. 
  3. Exercise. The more you move, the more your GI tract moves! Going for a quick walk can help with abdominal bloating and cramping.
  4. Over the counter medications, such as anti-diarrheals, can also be helpful. It is recommended to discuss this with your physician prior to starting. 


Sometimes our gut hurts and we don’t exactly know why. It is helpful to be able to identify what your symptoms are, what caused them, and how you can control them. Typical FODMAP reactions are bloating, abdominal pain, cramping, gas, loose stools and/or constipation and they are most likely to occur anywhere from 2-8 hours after eating or drinking. FODMAP reactions can still occur up to 48-72 hours later, which is why it is helpful to work with a trained dietitian to help you determine your trigger foods. If you do have a reaction, try at home remedies such as peppermint, heating pads, and exercise to help with your symptoms. To avoid high FODMAP foods in the first place, try the free Fig app.