Diarrhea involves passing loose stools frequently. It can result from various causes, such as infections and food intolerances, that may also lead to a loss of appetite.

Often, people experiencing diarrhea lose their appetite. This may be due to symptoms that accompany passing loose stools, such as nausea and abdominal pain.

This article explores some health problems that may cause diarrhea and loss of appetite. It also discusses how to treat and prevent diarrhea and when to speak with a healthcare professional.

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ByLorena/Stocksy United

The World Health Organization (WHO) defines diarrhea as passing three or more runny stools in a day or passing stools more often than usual for a particular person’s bowel habits.

According to the National Institute of Diabetes and Digestive and Kidney Disorders (NIDDK), people may lose their appetite for a brief time while experiencing diarrhea.

Several causes of diarrhea may also reduce a person’s appetite. Some of these include infections, digestive conditions, and reactions to treatments.

Dietary habits

Consuming certain foods and drinks may contribute to diarrhea or worsen it. Examples may include:

  • foods containing artificial sweeteners
  • alcoholic beverages
  • spicy foods
  • foods and beverages containing caffeine
  • dairy products
  • some fruits

Viral, bacterial, and parasitic infections

People may experience diarrhea and loss of appetite after contracting pathogens, such as bacteria, parasites, or viruses, by consuming contaminated food or water.

However, different pathogens can spread in several ways and cause infections that may include:

Intolerances and allergies

Some people have reactions to certain substances in foods or medications that can cause diarrhea and appetite loss, including those with:

Nutrient deficiencies and anemias

Difficulties in processing or absorbing certain vitamins or nutrients can lead to diarrhea and reduced appetite. These may include:

Inflammatory bowel diseases and other digestive conditions

Some conditions affecting the digestive system may trigger flares of diarrhea and loss of appetite, including:

Treatment side effects and overdoses

Some medications and surgeries may cause diarrhea and appetite loss as side effects. These may include:

Other causes

Other conditions may affect the digestive system and cause diarrhea and loss of appetite, including:

Some causes of diarrhea may only lead to a short bout of symptoms. Others are longer-term conditions that may require ongoing management.

Treatments for acute diarrhea

Acute (or short-term) diarrhea due to an infection may resolve without treatment. Many people will never know what caused their acute diarrhea. They may treat it with over-the-counter medications, including bismuth subsalicylate (Pepto-Bismol) and loperamide (Imodium).

However, those who experience diarrhea for 2 days or longer should speak with a doctor. People with diarrhea have a higher risk of dehydration and may need oral rehydration therapy to top up their levels of fluids and electrolytes.

Learn about what electrolyte drinks are and how to make them.

What to eat during diarrhea and appetite loss

Once diarrhea resolves, a person’s appetite usually returns. According to the NIDDK, it is not advisable to follow a restricted diet while having diarrhea.

However, those with reduced appetite during diarrhea might not feel comfortable to eat their usual diet. In this case, a person may try the following foods and beverages:

  • drinks with electrolytes, such as sports drinks and diluted fruit juices
  • bland foods, including toast, plain rice, and boiled potatoes
  • water
  • soups and broths

Managing chronic diarrhea and appetite loss

The treatment for ongoing or chronic diarrhea depends on the cause. For longer-term infections due to bacteria or parasites, a doctor may prescribe a medication to treat the specific infection.

They may also recommend consulting a dietitian to discuss a meal plan that excludes diarrhea-triggering ingredients in those who have intolerances or other conditions. These ingredients may include dairy products or gluten.

People need to speak with a doctor about chronic diarrhea. A healthcare professional can determine the underlying cause of the condition and provide appropriate treatment if necessary.

Preventing acute diarrhea involves washing the hands properly before and after preparing food, using the bathroom, or changing an infant’s diaper.

Anyone traveling to countries in which sanitation where developed should check the safety of drinking tap water, eating food from street vendors, and drinking unpasteurized local juices and milk. Drinking bottled water, soft drinks, and teas and coffee using boiled water may help reduce the risk of exposure to diarrhea-inducing infections.

People with a chronic condition that causes diarrhea can work with a doctor to understand what triggers their symptoms. They may then be able to maintain a diet and lifestyle that avoids these triggers.

Adults with the following symptoms need to seek immediate medical care:

Parents and caregivers need to take children to the doctor if they have diarrhea for more than 1 day or any of the other symptoms above.

Several different health conditions and other factors may cause diarrhea and appetite loss. These may include infections, digestive conditions, and taking certain medications.

Often, acute diarrhea will pass within a few days without treatment. Drinking fluids containing electrolytes can help reduce the risk of dehydration. People need to speak with a doctor about chronic diarrhea and appetite loss. They can help determine the underlying cause and recommend appropriate treatment if necessary.

A person may be able to prevent acute diarrhea by practicing good hygiene, for example, by washing their hands regularly. They may need to speak with a doctor to manage chronic diarrhea.