What Diarrhea After Eating Might Mean–and What You Can Do About It

Medically Reviewed By Adam Bernstein, MD, ScD
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Any diarrhea is due to a reduction in water absorption by the bowel or an increase in water secretion. Certain foods, infections, and medical conditions can cause diarrhea, including after eating. Diarrhea, or watery stool, is a common gastrointestinal issue. A 2018 survey reported that 20.2%, or 1 in 5 participants, experienced recent diarrhea.

Possible causes of diarrhea after eating include bacteria, viruses, or parasites. Sometimes, stomach pain and diarrhea after eating can result from a digestive system issue.

Keep reading to learn more about diarrhea after eating, possible causes, how to treat it, and when to contact a doctor.

Diarrhea explained

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Diarrhea happens when you pass three or more loose or watery stools per day or have more frequent passage than what is typical for you.

If you pass stool frequently but the stools have some shape or are sticky, you do not have diarrhea. Babies who are breastfed or chestfed may have loose but nonwatery stools; this is typical.

Diarrhea occurs when your large intestine does not absorb enough water and other digestive fluids from the digested matter in your large intestine, a 2021 research review explains. It can also happen if the intestine secretes, or discharges, more water than usual. In both scenarios, the contents within the intestine become watery.

Typically, this is what happens after you eat:

  1. Water, stomach acids, bile, and digestive enzymes help break down the food you ingest.
  2. The muscular wall of the small intestine contracts and relaxes to move food through your gastrointestinal tract. This is called peristalsis.
  3. Your small intestine absorbs the nutrients in the food and sends these nutrients into your bloodstream.
  4. Undigested food and waste enter the large intestine.
  5. Your large intestine reabsorbs sufficient water and digestive fluids to balance body fluids. Removing water and other fluid from the stool is what makes it more solid.
  6. Digestive enzymes and hormones stimulate contractions and periods of relaxation. This rhythm propels the food toward the rectum.
  7. When food enters the rectum and pressure increases, your gastrocolic reflex stimulates peristalsis for a bowel movement.

Related symptoms can include:

  • severe stomach pain or cramps
  • bloating
  • gas (flatus)
  • feeling that you need to pass stools, even though your bowels are already empty

Causes of diarrhea after eating

Infections, medical conditions, hormonal changes, and some foods can cause diarrhea.

Infections

Your gut supports colonies of bacteria that help keep your digestive system running smoothly. These colonies make up your microbiome.

Certain viruses, parasites, and harmful (pathogenic) bacteria can cause changes in your gut microbiome. These changes can affect the way your colon contracts and relaxes and cause diarrhea.

According to the World Health Organization (WHO), pathogens that may cause diarrhea, including diarrhea after eating, include:

Medical conditions

Some medical conditions can cause diarrhea. These include:

  • Irritable bowel syndrome (IBS): Changes in the gastrocolic reflex can cause diarrhea. A 2022 review mentions that the colon of people with IBS responds more strongly to the gastrocolic reflex. This strong response can cause diarrhea. Learn about IBS.
  • Inflammatory bowel disease (IBD): Frequent bowel movements, bouts of diarrhea alternating with constipation, and stomach cramps are signs of IBD, which includes ulcerative colitis and Crohn’s disease.
  • Celiac disease: Chronic diarrhea is one of the symptoms of celiac disease. This autoimmune condition causes a hypersensitivity to the gluten protein that is found most commonly in wheat products.
  • Microscopic colitis: This condition causes inflammation in the inner lining of the colon and rectum. The inflammation blocks the reabsorption of water from the digested food. Learn about microscopic colitis.

For people who have had bariatric surgery, dumping syndrome is a possible cause of diarrhea after eating. Dumping syndrome is a rare complication of weight loss surgery. Research suggests that weight loss surgery can negatively impact the gastrocolic reflex and lead to this syndrome.

Hormonal changes

Hormonal changes may cause diarrhea before and during the menstrual cycle, explains the Office on Women’s Health. Prostaglandins are hormones that cause contractions to help your uterus shed its lining, per a 2022 research review. These hormones also play a role in GI contractions, 2009 research explains.

Food intolerance

Worldwide, about 70% of people cannot tolerate lactose, a natural sugar found in the milk of mammals. If you cannot fully digest lactose, you may experience bloating, abdominal cramping, and diarrhea after eating dairy foods. Lactose intolerance is more common in babies and young children than in adults.

Another cause of diarrhea is sugar alcohols, such as sorbitol, mannitol, and xylitol. Found in sugar-free candies and gum, sugar alcohols cause diarrhea in some people, explains the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK).

How to relieve diarrhea after eating

Diarrhea treatment depends on whether your diarrhea is acute, persistent, or chronic, your age, and the underlying cause, explains the NIDDK.

Per the NIDDK:

  • Acute diarrhea lasts 1–2 days and typically goes away on its own.
  • Persistent diarrhea lasts longer than 2 weeks but fewer than 4 weeks.
  • Chronic diarrhea lasts 4 weeks or more and may be continuous or come and go with time.

A bacterial or viral infection that causes acute diarrhea may resolve on its own after a few days. The following remedies and treatments may help ease your symptoms:

  • Staying hydrated: Drinking plenty of water to replace the water that you are losing can prevent dehydration. The salt in plain broth can help your body retain water. Try to avoid alcohol, soda, and caffeinated drinks, which can all make your symptoms worse.
  • Eating bland foods: Aim for simple foods, such as bananas, white rice, plain toast, and applesauce to keep your energy levels steady. These low fiber foods can help make your stools firmer. Learn more about the BRAT diet.
  • Taking probiotics: Probiotic supplements contain gut-friendly bacteria that can replace the beneficial bacteria in your microbiome. Beneficial bacteria help suppress the bacteria that contribute to diarrhea. Probiotics can be found in yogurt and fermented foods. Talk with your doctor about using them to treat diarrhea, says the NIDDK.
  • Medication: Antidiarrheal medications, such as loperamide (Imodium) and bismuth subsalicylate (Pepto-Bismol), can help you manage your symptoms. However, medical professionals do not usually recommend these medications when bloody stools or fever accompany diarrhea. These symptoms are signs of a bacterial or parasitic infection.

Contact your doctor for guidance in managing diarrhea.

Learn more about diarrhea treatments.

When to see a doctor

Diarrhea may be due to a serious underlying condition. It can also lead to dehydration, which can become life threatening. According to the NIDDK, you should contact a medical professional right away if circumstances below occur.

Adults

Contact a physician for any of the following:

  • diarrhea for more than 2 days
  • 6 or more loose stools in 24 hours
  • severe pain in your abdomen or rectum
  • fever of 102° or higher
  • pus or blood in stool
  • symptoms of dehydration

Infants and young children

Contact a pediatrician for any of the following:

  • diarrhea for more than 24 hours
  • severe pain in the abdomen or rectum, which may manifest as more irritability, fussiness, or crying than is typical for the infant or young child
  • fever of 102° or higher
  • pus or blood in stool
  • symptoms of dehydration

Read Bloody Diarrhea: Causes and Treatments.

Diagnosing the cause

Research shows that less than 20% of people with abdominal pain, bloating, or diarrhea consult a doctor for an evaluation and help with managing their symptoms.

Diagnostic tests your doctor requests may depend on:

According to the NIDDK and a 2021 review of diarrhea, tests may include:

Your doctor will explain the results of your tests and develop a treatment plan as necessary.

Learn about diarrhea treatments.

Frequently asked questions

How do bananas help with diarrhea?

Bananas are high in potassium. This helps replace electrolytes that you lose because of diarrhea. Bananas also add bulk to the stools and make them firmer.

Do sugary foods make diarrhea worse?

Yes. Sugary foods and drinks, fruit, and fruit juice may make diarrhea symptoms worse — although fruit juice may be part of treatment to prevent dehydration. They contain fructose, and some people with an intolerance to it can get diarrhea. Sugar alcohols, such as sorbitol and xylitol, can also cause diarrhea.

Summary

Causes of diarrhea after eating include certain foods, infections, and ongoing GI conditions.

Regardless of when diarrhea occurs, you should contact a doctor if it lasts more than 2 days in an adult or 24 hours in an infant or young child. You should also contact a doctor for certain symptoms accompanying diarrhea, such as blood or pus in stool, fever, and symptoms of dehydration.

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Medical Reviewer: Adam Bernstein, MD, ScD
Last Review Date: 2022 Sep 9
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THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
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