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What Causes Anorexia? 160 Possible Conditions

A decreased appetite occurs when you have a reduced desire to eat. It may also be known as a poor appetite or loss of appetite. The medical term for this is anorexia.

A wide variety of conditions can cause your appetite to decrease. These range from mental conditions to physical illnesses.

If you develop a loss of appetite, you may also have related symptoms, such as weight loss or malnutrition. These can be serious if left untreated, so it’s important to find the reason behind your decreased appetite and treat it.

What causes a decreased appetite?

A number of conditions can lead to a decreased appetite. In most cases, your appetite will return to normal once the underlying condition is treated.

Bacteria and viruses

Anorexia can be caused by bacterial, viral, fungal, or other infections at any location. It could be the result of an upper respiratory infection, pneumonia, gastroenteritis, colitis, a skin infection, or meningitis, just to name a few. After proper treatment for the illness, your appetite will return.

Psychological causes

There are various psychological causes for a decreased appetite. Many older adults lose their appetites. Your appetite may also tend to decrease when you’re sad, depressed, grieving, or anxious.

Boredom and stress have also been linked to a decreased appetite.

Eating disorders, such as anorexia nervosa, can also lead to a decreased appetite overall. A person with anorexia nervosa undergoes self-starvation or other methods to lose weight. People who have this condition are typically underweight and have a fear of gaining weight. Anorexia nervosa can also cause malnutrition.

Medical conditions

The following medical conditions may cause your appetite to decrease:

Cancer can also cause loss of appetite, particularly if it’s concentrated in the following areas:

Pregnancy can also cause a loss of appetite during the first trimester.


Some medications and drugs may reduce your appetite. These include street drugs — such as cocaine, heroin, and amphetamines — along with prescribed medications. Prescription medications that reduce appetite include:

When to seek emergency treatment

Always contact your doctor right away if you begin to lose weight rapidly for no apparent reason.

It’s also important to seek immediate medical help if your decreased appetite could be a result of depression, alcohol, or an eating disorder such as anorexia nervosa or bulimia.

How is a decreased appetite treated?

Treatment for a decreased appetite will depend on its cause. If the cause is a bacterial or viral infection, you won’t usually require specific treatment for anorexia, as your appetite will quickly return once your infection is cured.

Home care

If anorexia is due to a medical condition such as cancer or chronic illness, it can be difficult to stimulate your appetite. However, eating with family and friends, cooking your favorite foods, or going out to eat at restaurants may help to encourage eating. Light exercise may help increase appetite, or you might consider focusing on eating just one large meal per day, with light snacks in between.

Eating frequent small meals can be helpful, and these are usually easier on the stomach than large meals. To ensure you’re getting enough nutrients from food, meals should be high in calories and protein. You may also want to try liquid protein drinks.

It can be useful to keep a diary of what you eat and drink over a period of a few days to a week. This will help your doctor to assess your nutritional intake and the extent of your decreased appetite.

Medical care

During your appointment, your doctor will try to create a full picture of your symptom. They’ll measure your weight and height and compare this to the average for the population.

You’ll also be asked about your medical history, any medications you take, and your diet. Be prepared to answer questions about:

  • when the symptom started
  • whether it’s mild or severe
  • how much weight you’ve lost
  • if there were any trigger events
  • if you have any other symptoms

It may then be necessary to conduct tests to find the cause of your decreased appetite. Possible tests include:

In some cases, you will be tested for pregnancy and HIV. Your urine may be tested for traces of drugs.

If your decreased appetite has resulted in malnutrition, you may be given nutrients through an intravenous line.

Your doctor may also prescribe oral medication to stimulate your appetite.

Your doctor may refer to you to a mental health specialist or counselor if your loss of appetite is a result of depression, an eating disorder, or drug misuse.

Loss of appetite caused by medications may be treated by changing your dosage or switching your prescription. Never change your medications without first consulting your doctor.

What is the outcome if decreased appetite is not treated?

If your decreased appetite is caused by a short-term condition, you’re likely to recover naturally without any long-term effects.

However, if your decreased appetite is caused by a medical condition, the condition could worsen without treatment.

If left untreated, your decreased appetite can also be accompanied with more severe symptoms, such as:

If your decreased appetite persists and you develop malnutrition or vitamin and electrolyte deficiencies, you can have life-threatening complications. Therefore, it’s important to seek medical attention if you have anorexia that does not resolve after an acute illness or that lasts longer than a few weeks.

Content licensed from:

Written by: Kati Blake
Medically reviewed on: Jun 19, 2017: Graham Rogers, MD

This feature is for informational purposes only and should not be used to replace the care and information received from your health care provider. Please consult a health care professional with any health concerns you may have.
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