Diarrhea During Fasting: When To Stop Fasting And Treatment Options

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SubscribeDiarrhea During Fasting and Other Side EffectsMedically reviewed by Saurabh Sethi, M.D., MPHWritten by Alex Snyder on October 7, 2019
  • Other symptoms
  • Causes
  • See a doctor
  • Treatment
  • Fasting benefits
  • Takeaway

Fasting is a process in which you severely restrict eating (and sometimes drinking) for a period of time.

Some fasts last for a day. Others last over a month. The duration of a fast depends on the person and their reasons for fasting.

If you experience diarrhea while fasting, you should end your fast until symptoms improve. Keep reading to learn why.

Diarrhea while fasting

Diarrhea occurs when the food and nutrients passing through the gastrointestinal (GI) tract move too quickly and exit the body without being absorbed.

Diarrhea during a fast may cause side effects such as:

  • dehydration
  • malnutrition
  • malabsorption
  • cramping
  • nausea
  • dizziness

Diarrhea and side effects like dizziness during a fast can be stressful and dangerous. While fasting, your body is already more likely to be dizzy, tired, and nauseous. These are only made worse with diarrhea.

For some people, the combination of fasting and diarrhea can even lead to passing out.

For these reasons, it’s recommended to end your fast until symptoms improve, and then continue to fast once you’re no longer experiencing diarrhea and its side effects.

Other symptoms that signal you should end your fast

Along with diarrhea, consider ending your fast if you experience:

  • dizziness
  • loss of consciousness
  • nausea and vomiting
  • abdominal pain
  • chest pain

Causes of diarrhea during fasting

During a fast, diarrhea may occur because of an oversecretion of water and salts in the GI tract. A number of triggers can cause this, including drinking liquids high in caffeine, such as tea or coffee.

Usually, fasting doesn’t cause diarrhea on its own. In fact, you’re more likely to get diarrhea from breaking your fast than you are while performing the fast. That’s because your bowel’s ability to function properly decreases when it’s not used.

Other common causes of diarrhea include:

  • poor diet
  • lactose intolerance
  • mineral deficiencies
  • colitis
  • Crohn’s disease
  • infection
  • food or medication allergy

When to see a doctor

Before starting a fast — or if you have health concerns while fasting, including diarrhea — it’s a good idea to see a doctor.

Diarrhea is uncomfortable, but it’s usually not life-threatening. However, if you’re experiencing any of the following symptoms alongside diarrhea, contact your doctor immediately:

  • bloody stool (blood in diarrhea)
  • pain during bowel movement
  • swelling around bowel

Treating diarrhea

Depending on the cause of your diarrhea, the treatment will vary.

Home remedies

You can treat many cases of diarrhea at home with some quick dietary changes:

  • Drink lots of water.
  • Avoid sugary and caffeinated drinks.
  • Drink diluted juice, weak tea, or electrolyte-replacement, drinks like Gatorade or Pedialyte.
  • Increase foods high in soluble fiber.
  • Increase foods high in potassium and salt.

Medications

If home remedies aren’t helping, you may get relief from over-the-counter medications, including:

  • loperamide (Imodium)
  • bismuth subsalicylate (Pepto-Bismol)

Ending your fast due to diarrhea

When ending your fast because of diarrhea, consider starting with the BRAT diet (banana, rice, applesauce, toast).

This diet features food that’s bland, starchy, and low in fiber. It helps firm stools and replace lost nutrients.

You should also:

  • Eat small meals.
  • Avoid fried food.
  • Avoid foods that cause gas, such as beans and broccoli.

Why do people fast?

Some people fast for health reasons, while others fast for religious or spiritual reasons.

Advocates of fasting suggest that the practice yields the following benefits:

  • reduced inflammation
  • decreased risk of heart disease and diabetes
  • weight loss
  • body detoxification
  • improved gastrointestinal function

The Mayo Clinic suggests that regular fasting may decrease LDL (bad) cholesterol levels and may improve the way your body metabolizes sugar.

However, there’s very little scientific evidence about the effects of fasting on the human mind and body.

Since going without food for long periods of time is taxing on the body, it’s important to be aware of any problems that may arise during a fast, such as diarrhea.

Takeaway

Diarrhea is a common GI problem that everyone experiences from time to time. Diarrhea can be particularly debilitating — and dangerous — while fasting.

If you experience diarrhea while fasting, consider breaking your fast. You can always continue your fast once the diarrhea subsides.

If you experience any worrying symptoms, such as dizziness, loss of consciousness, nausea, vomiting, or bloody stools, contact a doctor immediately.

 

How we reviewed this article:

SourcesHistoryHealthline has strict sourcing guidelines and relies on peer-reviewed studies, academic research institutions, and medical journals and associations. We only use quality, credible sources to ensure content accuracy and integrity. You can learn more about how we ensure our content is accurate and current by reading our editorial policy.
  • Finnell JS, et al. (2018). Is fasting safe? A chart review of adverse events during medically supervised, water-only fasting. DOI:https://dx.doi.org/10.1186%2Fs12906-018-2136-6
  • Flescher M. (2003). Diarrhea and diet.https://badgut.org/information-centre/health-nutrition/diarrhea-and-diet/
  • Guelinckx I, et al. (2016). Contribution of water from food and fluids to total water intake: Analysis of a French and UK population surveys. DOI:https://dx.doi.org/10.3390%2Fnu8100630
  • Lopez-Jimenez F. (2019). Fasting diet: Can it improve my heart health?https://www.mayoclinic.org/diseases-conditions/heart-disease/expert-answers/fasting-diet/faq-20058334
  • News analysis: Does the 5:2 fast diet work? (2013). https://www.nhs.uk/news/food-and-diet/news-analysis-does-the-52-fast-diet-work/
  • Nutritional management of diarrhea. (n.d.). http://www.cancer.med.umich.edu/files/nutritional-managementof-diarrhea.pdf

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Medically reviewed by Saurabh Sethi, M.D., MPHWritten by Alex Snyder on October 7, 2019

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