What causes poop immediately after eating?

What causes poop immediately after eating?

Often, people can feel the urge to poop right after eating. When this happens, the person may feel like the food passes through them straight away. This is not the case however.

Yes, it can take 1–2 days before food finishes its journey through the digestive tract of a human. So a person who poops shortly after eating is likely to pass food they ate a day or two before.

The gastrocolic reflex is most likely the cause of having to poop right after feeding. This reflex is a natural involuntary reaction to food coming into the stomach. The strength of the gastrocolic reflex can, however, differ between individuals.

We explain what happens during the gastrocolic reflex in this article and address the factors that can increase its severity. We also describe the factors relating to diet and lifestyle that that help to minimize the urge to poop right after eating.

Why does it happen, and is it normal?

A lady eating food
It can take 1–2 days for food to pass through the digestive tract.

A natural involuntary response to food entering the stomach is the gastrocolic reflex, or gastrocolic response.

The body releases a hormone when food enters this organ which causes the colon to contract. Such contractions push food previously eaten deeper into the digestive system, which may contribute to the desire to pass through the stool.

The gastrocolic reflex is normal for certain people and causes no symptoms. Gastrocolic reflex is strong for some and the urge to poop after eating can be particularly extreme.

Conditions that can affect the gastrocolic reflex

Gastrocolic reflex can be impaired by other health conditions. For example, irritable bowel syndrome (IBS) can cause an individual’s digestive tract to push food at a much faster rate through their body.

Other conditions which may cause a person to move stool faster than normal include:

Each of the above conditions may increase gastrocolic reflex strength, resulting in an urge to poop shortly after eating. Often, they may cause additional digestive symptoms, such as:

  • bloating that subsides after passing gas or stool
  • a frequent need to pass gas
  • abdominal pain or discomfort
  • mucus in the stool
  • diarrhea
  • constipation
  • alternating diarrhea and constipation

Gastrocolic reflex vs. fecal incontinence

Diarrhea is a possible cause of fecal incontinence.
Diarrhea is a possible cause of fecal incontinence.

Fecal incontinence is another possible reason for having the need to throw up. The severity of the disorder can range from mild to a total loss of bowel control.

Fecal incontinence differentiates fairly easily from the symptoms of an extreme gastrocolic reaction to food. Fecal incontinence, in particular, may occur at any time. This is not just after eating that happens.

For a variety of different reasons a person can develop fecal incontinence including:

  • diarrhea
  • nerve damage in the rectum
  • damaged muscles in the rectum
  • damaged rectal walls
  • rectocele
  • rectal prolapse

People worried about potentially getting fecal incontinence should see their doctor for a diagnosis. A doctor can clarify the many different ways in which fecal incontinence is handled and controlled.

Gastrocolic reflex vs. diarrhea after eating

Following a meal an episode of diarrhea is unlikely to contribute to the gastrocolic reflex of the individual.

Diarrhea is a chronic disorder usually lasting just a day or two. Nonetheless, an underlying health problem may be suggested by diarrhea that lasts a week or more.

Some common causes of residual diarrhea include:

  • excessive consumption of artificial sweeteners and other laxatives
  • foodborne bacteria and parasites
  • food intolerances
  • food allergies
  • digestive disorders
  • viral infection
  • previous abdominal surgery, such as gallbladder removal

When to see a doctor

The gastrocolic reflex is a normal response to food coming into the stomach. Feeling the need to poop after eating always does not warrant a doctor visit.

However, a person should see their doctor if they experience the following:

  • intense and frequent gastrocolic responses to food
  • diarrhea lasting longer than 2 days
  • additional gastric symptoms

The above symptoms could indicate a possible underlying health issue.

Treatment and prevention

Since the gastrocolic reflex is a natural body reaction, treatment is not medically required. There are also steps people may take to help reduce the gastrocolic reflex strength and the resulting urge to poop.

Seek treatment for underlying digestive conditions

Individuals will see a doctor if the desire to vomit up after eating is followed by other gastric symptoms.

A doctor can carry out tests to diagnose any underlying health conditions, depending on the duration and severity of those symptoms.

If a condition is present, treatment of it can help to reduce the gastrocolic reflex strength.

Changing the diet

Some foods are more likely than others to cause an intense gastrocolic response. These include:

  • fatty or greasy foods
  • dairy products
  • foods high in fiber

Keeping a food diary may help an individual recognize foods that can worsen their gastrocolic response. The diary will provide a record of the foods the person consumes, as well as their digestive response to the foods.

When a potential trigger food has been recognized by the person they will actively avoid the food and see if their symptoms are improving.

Managing stress

Stress may increase the strength of the gastrocolic reflex for some people. Such individuals may benefit from programs that help to relieve stress. Examples include meditation, and exercise.


Stool passage immediately after a meal is typically the result of the gastrocolic reflex, which is a natural body response to food entering the stomach.

Quick everyone will feel from time to time the symptoms of the gastrocolic reflex. Its strength, though, can vary from person to person. Some lifestyle factors that help to lessen the urge to poop after a meal.

After a meal, people should see a doctor if they still have diarrhea or other gastric symptoms. Such symptoms can suggest an underlying health condition requiring medical attention.