Gastrocolic Reflex: Urgent Diarrhea or Distended Belly after Eating (2024)

Kathryn Adel July 30, 2018 FODMAP, Health, IBS Irritable Bowel Syndrome

This article was originally written on July 30, 2018 and fully updated on May 11, 2023

Do you tend to run to the bathroom or see your belly expand very quickly after eating? This is the case for many people who have irritable bowel syndrome (IBS), and it can be caused by what is called the gastrocolic reflex. Digestive symptoms caused by malabsorption such as an intolerance to FODMAPs or sucrose, or pancreatic insufficiency (fat malabsorption) take longer to appear, on average between two and eight hours after eating.

Think about it, you have to give the food time to be digested.So how is it possible to have symptoms so quickly? Read this article to learn more!

The gastrocolic reflex

The gastrocolic reflex is a normal reflex that is triggered by eating and helps the intestine “make room” for the food you have just eaten. This reflex stimulates the intestine (mainly the colon) to contract and move its contents. A larger stretch or a large amount of fat can send a stronger signal. This reflex can therefore be intensified if you eat a very fatty meal, a large portion, foods high in roughage such as a large salad or popcorn, or even if you drink a large cold drink very quickly.

Studies have shown that some people with IBS seem to have an exaggerated gastrocolic reflex. This means that their intestines can contract more intensely in response to a meal, contributing to IBS symptoms.

For people with diarrhea-prone IBS (IBS-D), this can lead to urgent and diarrhea very soon after eating. For IBS sufferers with constipation (IBS-C), this can lead to flatulence and significant belly distension as the intestine fills up, but the body is unable to pass stools and free up space. Digestive symptoms caused by an intensified gastrocolic reflex appear on average between 15 and 90 minutes after eating.

How Can I Reduce Symptoms Resulting from the Gastrocolic Reflex?

Sometimes, simply avoiding overeating, reducing portions of roughage (salad, nuts, popcorn, etc.), eating smaller meals and/or snacks more often, avoiding very high-fat meals (ex. fried foods) and avoiding drinking large amounts of cold drinks can help control symptoms related to the gastrocolic reflex.
For those who suffer from IBS-C, this reflex can sometimes be useful to help with bowel movements. Thus, we can try to include a little more healthy fats at breakfast such as a handful of nuts or two tablespoons of nut butter, or a glass of cold water to try to stimulate a bowel movement.

To reduce unpleasant symptoms and digest your meals better, I suggest you keep a food diary and work with a dietitian to identify the foods, or food groups, that cause problems. Given that digesting a food takes several hours, it’s vital to keep in mind the foods you ate during previous meals.

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