Diarrhea after eating, also known as “postprandial diarrhea,” is a very specific subset of bowel trouble.
Normally, it takes anywhere from 12 to 48 hours, sometimes more, for your body to pass stool in response to something you have recently eaten.
Experiencing bowel movements immediately after eating a meal or within a few (under three to five) hours is therefore unusual and a sign that something is causing your intestines to move much faster than normal.
Sometimes you may even experience stomach pain and diarrhea after eating, or stomach cramps and diarrhea after eating, which should definitely be taken as a sign of a problem.
Exploring Diarrhea after Eating
After food is digested, the resulting feces come to rest in the colon in a highly watery state. Over time, much of the water gets reabsorbed by the body and the feces firms up into a more solid and familiar shape. As more mass is added to the feces, it will eventually reach a point where it presses on one of the nerves that govern defecation. This triggers a series of responses known as the defecation reflexes.
As the name implies, the result of these reflexes is a bowel movement. If the reflex triggers too early, you end up with watery stool and if this happens more than once per day, you have diarrhea. In cases of diarrhea after eating, something is causing the triggering nerves to be extra sensitive and irritated which makes them overreact when even a minor stimulus is present, such as the still-watery feces from a recent meal.
Incidentally, although most defecation is controlled by the colon’s nerves, it can be triggered further up the gastrointestinal tract by certain other mechanisms. The two others most likely to be involved in cases of diarrhea after eating are the gastrocolic reflex and the duodenocolic reflex, which trigger defecation in response to stretching of the stomach and start of the small intestine, respectively. Whether these two are involved in your specific situation will naturally depend on what the underlying cause is.
What Causes Diarrhea after Eating?
Diarrhea is divided into acute and chronic conditions. Acute means sudden-onset and usually refers to short-lived or one-off instances. If you continue to experience diarrhea for around three weeks or more, it moves into chronic territory. This distinction is important since some diarrhea causes fall into only one category, so knowing the differences between them can help narrow the diagnosis.
Acute Causes of Diarrhea after Eating
- Food poisoning: The good news is that your body is very good at noticing when it has eaten something it shouldn’t. The bad news is that this can result in diarrhea as shortly as 20 minutes after eating the contaminated food.
- Viral infection: Various viruses from Norwalk to viral hepatitis can make your intestines or stomach extra sensitive and more likely to jump the gun on the defecation reflex.
- Lactose intolerance: Lactose is a sugar that normally gets broken down by lactase, a digestive enzyme. Those with lactose intolerance don’t have enough lactase, which causes lactose to be carried to the colon where it can trigger an early bowel movement.
- Fructose intolerance: Similar to lactose intolerance, some people are unable to properly digest fructose, which causes fructose intolerance.
- Parasites: Certain foodborne parasites, such as tapeworms, can trigger acute diarrhea upon first being ingested. If a parasite manages to take up residence, you may continue to experience sporadic diarrhea later on.
- Toddler’s diarrhea: This is a bout of diarrhea that can sometimes become chronic. It’s triggered by giving too much fruit juice to an infant, since the sugars drag excess water into the bowel.
- Magnesium: Overdose-levels of magnesium can make you more prone to bouts of diarrhea after eating. It’s almost impossible to reach the triggering amounts without taking a magnesium supplement, which people some do since it can be used as a laxative.
Chronic Causes of Diarrhea after Eating
- Irritable bowel syndrome (IBS): Some sufferers of IBS find that their gut is so sensitive they can suffer diarrhea shortly after eating.
- Celiac disease: This is an autoimmune reaction to eating gluten, one of which can be a sudden bout of diarrhea. Due to the effects of celiac disease and the retention of gluten, the resulting stool will be more likely to float or be strong-smelling.
- Bile acid malabsorption (BAM): Bile acids are produced by the gallbladder to help you digest fats. They are normally reabsorbed but if this doesn’t fully happen, the acids will stick around and annoy your intestines. BAM is triggered by surgery or digestive illness, but sometimes it has no known origin.
- Dumping syndrome: This is a possible complication of certain weight-loss surgeries. Dumping syndrome causes the stomach to empty too quickly into the small intestine, triggering the duodenocolic reflex.
Recognizing the Symptoms of Diarrhea After Eating
Diarrhea can be accompanied by various other symptoms. Paying attention to what accompanies your bowel issues can help inform your doctor and result in a more accurate diagnosis. Some of the symptoms to keep in mind are:
- If you get yellow diarrhea after eating, it could be a sign that something is up with your gallbladder.
- Black feces means you’ve digested some blood, so there may bleeding somewhere in the upper gastrointestinal tract.
- Conversely, bright red blood indicates bleeding along the lower gastrointestinal tract.
- A fever indicates that there’s an infection.
- Vomiting also indicates the presence of an infection.
- Bloating can imply bacterial causes, IBS, or other digestive disorders.
- Abdominal cramps or pain suggest illness or IBS.
- Dry mouth or skin, excessive thirst, weakness, dizziness, and minimal urine or dark urine are signs of dehydration and should be treated immediately.
Do Fatty Foods Cause Diarrhea After Eating?
Some people find that they get diarrhea only after eating certain foods. If this is the case, it may help narrow down the underlying cause. Fat is one of the bulkier components in stool and is consequently able to provoke a sensitive gut more easily than other nutrients. Diarrhea after eating fatty foods suggests an irritable bowel disorder or a digestive disorder that affects your ability to process fats.
Limit or Avoid These Foods to Prevent Diarrhea After Eating
- Fattening foods: Oil, butter, cream cheese, salad dressing, and fattening desserts.
- Foods that cause gas: Beans, prunes, peas, and chickpeas.
- Dairy: Ice cream, cottage cheese, and milk.
- Foods high in fiber: Raw fruits and vegetables, oatmeal, and whole grains.
Food Triggers and Diarrhea
Diarrhea after Eating a Salad
Although uncommon, you may find yourself experiencing bouts of diarrhea after eating a salad or lettuce (you may even find signs of lettuce when looking at the stool itself). Lettuce and similar plants are largely insoluble fiber, which means that they will pass through without getting digested. If your diet consists primarily of insoluble fiber, which can happen in cases like the Paleo diet, salad can become capable of triggering diarrhea. You may also be eating a lot of salad that hasn’t been washed properly or is otherwise contaminated, so keep that possibility in mind too.
Diarrhea after Eating Out
If you are getting diarrhea after eating out but not from any singular restaurant, you may have a dietary intolerance or sensitivity. Consider the differences in what you eat at home versus what you eat out. Are there any ingredients unique to the restaurant food? While you should always get a proper diagnosis for dietary conditions, these questions can help you and your doctor figure out what to check for.
Diarrhea after Eating Eggs (Are Eggs the Culprit?)
If you get diarrhea after eating eggs then the culprit is probably salmonella. Eating eggs raw might have looked cool (or gross) in Rocky, but cooking them is a better idea. But if the eggs are spoiled or contaminated, there’s a good chance diarrhea will follow. Another possibility is that that you’re allergic to eggs, so it’s worth getting tested to be certain.
How to Treat Diarrhea after Eating
There are only a small handful of options that can be used to treat in-progress bouts of diarrhea.
The most important thing to remember when treating diarrhea is to stay hydrated. As mentioned earlier, diarrhea is watery because you defecate before enough fluid has been reabsorbed by the body. This means that dehydration is a very real threat when suffering diarrhea. You should have at least one cup of liquid after every diarrheic bowel movement. This can include water, clear fruit juice, flat ginger ale, soup broth, or other drinks. Avoid alcohol since it can make things worse.
2. Medication or Infection
Medical options are going to depend on the cause. If you have food poisoning or an infection, your doctor can prescribe antibiotics, antivirals, or antiparasitics to treat the underlying culprit. Since these drugs are type-specific, it’s important to make sure you know what needs to be treated before taking one blindly if you want to avoid taking a drug that turns out to be ineffective.
3. Anti-Diarrhea Treatment
Some over-the-counter options for diarrhea exist, such as Pepto-Bismol, but they may not be appropriate in cases of infection. Remember that the diarrhea you get from something like food poisoning is your body trying to expel the pathogen and this process should be allowed to happen when possible. Since certain infections or other medical conditions can be made worse by using diarrhea medicines, you should double-check with your doctor before using one.
4. Gentle Foods
Your bowels may be sensitive following a bout of diarrhea, especially if it was brought on by food poisoning. Try easing your gut back to a normal diet by starting off with semi-solid or easily digestible foods including toast, soda crackers, or soup.
Preventing Diarrhea after Eating (Lifestyle Changes for Diarrhea after Eating)
In contrast to treating active diarrhea, prevention is a much simpler and easier task since it primarily involves avoiding possible triggers and making sure your food is washed properly. The individual measures that need to be taken will vary depending on the underlying cause, so not all of these tips will be applicable to every person.
- Wash fruits and vegetables thoroughly before eating.
- Cook meat to a proper temperature.
- Make dietary adjustments to avoid triggering nutrient sensitivities.
- Use added enzymes (lactase, etc.) before eating something with a triggering component.
- Eat several small meals throughout the day instead of the standard three large ones.
- Eat probiotic foods to help improve your gut flora.
- Avoid known aggravators such as fatty, spicy, or highly seasoned foods during the post-diarrhea recovery period to avoid relapse.
When to Contact a Doctor
It’s highly advisable to contact your doctor or seek medical attention if you start to experience any of the following:
- Diarrhea persists for more than three weeks on-and-off, or constantly happens for three days.
- Diarrhea is accompanied by a fever, especially one higher than 102 degrees Fahrenheit.
- Diarrhea is accompanied by severe abdominal or rectal pain.
- Diarrhea is bloody, black, or gray.
- You begin to show signs of dehydration (excessive thirst, dizziness, weakness, etc.).
Additionally, special care needs to be taken when monitoring an infant who suffers from diarrhea. Infants are more susceptible to dehydration from diarrhea and medical attention should be sought if they start to show the following:
- The infant hasn’t wet their diaper in over three hours.
- The baby cries without tears.
- The infant has a sunken appearance around the eyes, cheeks, or abdomen.
- The skin is not immediately smooth after a brief pinch.
- The infant is unusually drowsy, sleepy, irritable, fussy, or is unresponsive.
Sources for Today’s Article:
“What to Do for Chronic Diarrhea after Eating,” About web site, last updated March 11, 2016; http://ibs.about.com/od/diarrhea/a/Diarrhea-After-Eating.htm, last accessed April 11, 2016.
Morris, S., “Why Is My Stool Yellow?” Healthline web site, last reviewed on April 21, 2015; http://www.healthline.com/health/digestive-health/yellow-stool#Overview1, last accessed April 11, 2016.