Why You Get Diarrhea After Eating and Remedies

Diarrhea after eating, also called postprandial diarrhea, can be caused by many things, ranging from lactose intolerance and food poisoning to more serious concerns like inflammatory bowel disease (IBD) or colon cancer. Whether the condition is acute (sudden and severe) or chronic (persistent or recurrent), there are things you can do, such as changing your diet or using probiotics, to help ease the condition.

Jump to Key Takeaways.

What Causes Acute Diarrhea After Eating?

Acute diarrhea comes on suddenly and unexpectedly after eating. It typically gets better on its own after one or two days.

Food Poisoning

When diarrhea comes on shortly after eating, it is often caused by a food that you ate. Food poisoning comes on quickly and may be accompanied by other symptoms such as:

• Stomach pain or cramps
• Nausea
• Vomiting
• Fever

If the fever is over 102°F or if the diarrhea lasts more than three days, the food poisoning is considered severe, and you should seek care from a healthcare provider.

There are certain foods that are riskier when it comes to food poisoning, including:

• Raw or undercooked poultry or meat
• Raw or undercooked sprouts, especially alfalfa and bean sprouts
• Unwashed fresh fruits and vegetables
• Cut melon left out for more than two hours
• Unpasteurized juice or cider
  
• Unpasteurized (raw) milk and dairy products made from raw milk
• Raw or undercooked (runny) eggs or foods that contain them
• Raw or undercooked fish or shellfish
• Raw dough or raw batter made with raw (uncooked) flour

In most cases, food poisoning resolves on its own, but drink plenty of liquids to avoid dehydration.

Stomach Flu

When you get the stomach flu, also called viral gastroenteritis, symptoms may come on suddenly and may appear after eating. In addition to watery diarrhea, you may also experience other symptoms, such as:

• Pain or cramping in your abdomen
• Nausea or vomiting
• Fever

Dehydration is a common complication of the stomach flu. Fatigue, extreme thirst, light-headedness, and dark colored urine or not urinating enough are signs that you may be dehydrated.

The stomach flu is usually not dangerous, unless dehydration becomes severe. Seek care if you are unable to manage dehydration or if other symptoms appear.

Parasites

Intestinal parasites are not commonly seen in developed countries but can occur in people with compromised immune systems. Symptoms include:

• Diarrhea
• Dysentery
• Abdominal pain
• Nausea
• Vomiting
• Anal or perianal itching

In addition to these symptoms, nutritional deficiencies, including iron deficiency anemia, can also occur.

If you suspect a parasitic infection, see your healthcare provider to get a stool test for diagnosis. If you test positive, anti-parasitic medications are available for treatment.

Medication

Certain medications can cause loose, watery stools, which may occur after eating. Common culprits include:

• Laxatives (especially when taken in excess)
• Antacids that contain magnesium
• Antibiotics
• Metformin
• Chemotherapy medicines
• Drugs used to treat heartburn and stomach ulcers (such as Prilosec, Nexium, or Prevacid)
• Medicines that suppress the immune system (such as mycophenolate)
• Nonsteroidal anti-inflammatory drugs (NSAIDs)

If you experience medication-related diarrhea, work with your provider to come up with a solution. Treatments may be as simple as taking a probiotic supplement or eating yogurt.

Magnesium Supplements

Taking too much magnesium or taking supplements that contain too much magnesium can lead to diarrhea, which may occur after eating. Nausea and abdominal cramping may also occur.

The types of magnesium most commonly reported to cause diarrhea include magnesium carbonate, magnesium chloride, magnesium gluconate, and magnesium oxide.

The tolerable upper intake level (UL) for magnesium is 350 milligrams daily for adults. Taking magnesium in moderate amounts is not likely to cause problems.

What Causes Chronic Diarrhea After Eating?

Chronic diarrhea after eating can be a symptom of several health conditions. For people with these conditions, a snack or meal can be enough to trigger an episode of diarrhea.

There are many reasons why you might have diarrhea after eating, as a long-term symptom rather than a temporary problem.

Lactose Intolerance

People who have lactose intolerance do not have enough of the enzyme needed to break down a sugar found in milk and milk products (lactose). People who are lactose intolerant can get diarrhea after eating dairy foods.

While dairy products are the most common source of lactose, the sugar can also be found in foods you may not expect, including:

• Battered or fried foods
• Salad dressing
• Soups
• Chocolate or caramel
• Luncheon meats, hot dogs, sausages 
• Brown sugar and other flavorings
  
• Certain cocktails

Toddler's Diarrhea

Chronic nonspecific diarrhea of childhood, also called toddler's diarrhea, can be a cause of diarrhea in children who are otherwise healthy. Symptoms include:

• Having between five and 10 loose, watery, large stools per day
• Stools with undigested food particles
• Diarrhea lasting weeks, followed by weeks of normal bowel movements

There are a range of factors that can contribute to the condition, including:

• Excessive fluid intake
• Malabsorption of carbohydrates (often from foods like fruit juices)
• A low-fat/high-fiber diet, especially in children who prefer fruits, veggies, or grains over meat
• Immature or undeveloped digestive tract

If you suspect the condition or if you notice other symptoms, including blood in the stool, chronic fever, or severe abdominal pain, seek care from your child's pediatrician.

Gallbladder Surgery

If you have had a recent removal of the gallbladder, known as cholecystectomy, you may experience watery stools for weeks after the procedure. The complication occurs in 10% to 20% of people who have had their gallbladders removed.

If you experience this symptom, it is likely to resolve in the days and weeks following gall bladder surgery. You can try anti-diarrheal medications such as Imodium A-D for relief. If symptoms don't resolve, contact your care team for treatment.

Sugar Malabsorption

Some people can’t digest the sugars fructose and sorbitol. Eating these sugars may cause diarrhea after eating. This is broadly referred to as sugar malabsorption.

Fructose is found in many fruits and in high-fructose corn syrup. Sorbitol is found in some fruits and artificial sweeteners.

Glucose-galactose malabsorption (GGM) is an inherited disease mainly seen in children who lack the digestive enzymes to break down and absorb glucose.

Celiac Disease

People with celiac disease have an immune reaction to a protein found in wheat, rye, and barley called gluten. It is thought to be autoimmune, meaning that the immune system will launch an inappropriate attack on the intestines when gluten is introduced.

Diarrhea that’s caused by celiac disease is often very smelly. The stool is also more likely to float than sink. The avoidance of gluten is the primary form of treatment.

Inflammatory Bowel Disease (IBD)

The two forms of inflammatory bowel disease (IBD)—Crohn’s disease and ulcerative colitis—can cause diarrhea after eating. IBD has long been thought to be an autoimmune disease, but research suggests that the chronic inflammation may be due to the immune system attacking harmless bacteria in the intestines.

People with IBD may also have bloody diarrhea, along with abdominal pain, cramping, fever, and the need to go to the bathroom urgently.

Microscopic Colitis

Collagenous and lymphocytic colitis are types of microscopic colitis, an inflammation of the large intestine that causes persistent watery diarrhea. It gets its name from the fact that it can only be identified under a microscope, and that tissue will appear normal when viewed during a colonoscopy.

Diarrhea that doesn’t improve with treatment is typical of microscopic colitis. It can occur immediately after eating or on an ongoing basis.

Irritable Bowel Syndrome (IBS)

Irritable bowel syndrome (IBS) can also be a cause of diarrhea after eating. It is a poorly understood condition that causes a group of symptoms, including abdominal pain and changes in bowel movements (such as diarrhea, constipation, or episodes of both).

When diarrhea is the main feature, it is referred to as irritable bowel syndrome with predominant diarrhea (IBS-D).

With IBS, you experience symptoms without any visible signs of damage or disease in your digestive tract.

Bile Acid Diarrhea

Bile acid diarrhea is caused by the excess production of digestive fluid known as bile. The gallbladder secretes bile to help your digestive system break down fats. But when bile accumulates, it triggers contractions and the excess release of fluid from your large intestines. Diarrhea is the result.

Bile acid diarrhea is common after gallbladder removal surgery but can also occur due to an illness involving the gallbladder, pancreas, small intestine, or other digestive organs.

Pancreatic Exocrine Insufficiency

In people who have pancreatic exocrine insufficiency, the pancreas does not produce enough pancreatic enzymes to fully digest the foods that they eat. This can lead to diarrhea along with abdominal pain, a constant feeling of fullness, a loss of appetite, and weight loss.

The most common cause of pancreatic exocrine insufficiency is chronic pancreatitis, followed by pancreatic tumors and pancreas resection surgery.

Dumping Syndrome

Dumping syndrome is most common among people who have had bariatric surgery for weight loss. The condition is also called rapid gastric emptying because the stomach empties its contents into the small intestine faster than it should.

Eating can trigger diarrhea in people with dumping syndrome, especially when snacks or meals have a lot of sugar in them.

Colon Cancer

Chronic diarrhea is not typically a sign of colon cancer; constipation is more likely. With that said, it is not uncommon to have intermittent bouts of constipation followed by an episode of explosive diarrhea.

This is because fluids can start to accumulate if hardened stool blocks the intestines for a prolonged period. The inflammation can cause the walls of the intestines to release fluids that cause stools behind the plug to become watery.

Blockages like these are common due to the narrowing of the intestines (called strictures) in people with advanced colon cancer. Other symptoms include bloody stools, mucus in stools, abdominal cramping, fatigue, and unintended weight loss.

How to Relieve Diarrhea After Eating

Here are some things to keep in mind if you have diarrhea after eating. These tips can help ease the symptoms or even prevent them from happening.

• Stay hydrated: Your body won’t absorb fluids and minerals when you have diarrhea because of how quickly stool is passing through your system. Make sure to drink extra water, clear fruit juice, rice water, or broth to replace the lost fluids. You can also try drinking ginger tea when you have diarrhea to soothe your stomachache.
• Eat bland foods: The BRAT diet, which stands for bananas, rice, applesauce, and toast, is often recommended temporarily to relieve diarrhea symptoms. These foods are low in fiber and easy to digest. They are also starchy, which helps bind loose stools. Avoid foods that can worsen diarrhea, like dairy products, fatty foods, and foods that give you gas.
• Take probiotics: Consuming probiotics may help relieve diarrhea symptoms by restoring the balance of bacteria in your gut. You can get probiotics by taking a probiotic supplement or consuming probiotic foods, such as yogurt, kefir, kombucha, kimchi, and sourdough bread.
• Use relaxation exercises: Deep-breathing exercises and the strategic tensing and relaxing of muscles throughout the body (progressive muscle relaxation) can be effective in calming your body. They may also help slow the emptying of your bowels.
  
• Use medications cautiously: There are several over-the-counter (OTC) diarrhea treatments available, but they are not always recommended. Products like Imodium (loperamide), Kaopectate, or Pepto-Bismol (both bismuth subsalicylate) should not be used if you have a fever, or mucus or blood in your stools. If in doubt, ask your healthcare provider for advice.

Keep in mind that these medications should not be given to children without their pediatrician’s OK.

When to Call Your Healthcare Provider

There are some signs and symptoms along with diarrhea that could indicate a more serious health problem. Call your provider right away if you also have any of these symptoms:

• Blood in your stools
• Feces that look like coffee grounds, which could mean bleeding in your GI tract
• Dehydration symptoms (decreased urine, dry mouth, sunken eyes)
• Fever of 102 degrees or higher
• Severe stomach pain
• Frequent vomiting
• Diarrhea that doesn’t get better within two days
  

Key Takeaways

• Acute causes of diarrhea after eating include food poisoning, stomach flu, intestinal parasites, or a reaction to a medication.
• Chronic causes of diarrhea after eating include lactose intolerance, sugar malabsorption, or irritable bowel syndrome (IBS)
• If you experience diarrhea after eating, stay hydrated by drinking plenty of fluids, eat bland foods, try relaxation exercises, and use medications with caution.