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Diagnosing an Eating Disorder


People who have an eating disorder may eat too little or too much food. They may also be preoccupied with their shape or weight.

Eating disorders can affect anyone. But females in the United States are twice as likely as males to have the illness, according to the National Eating Disorders Association (NEDA).

There are four main types of eating disorders:

  • Anorexia nervosa: People with this condition don’t eat enough. And they may have an extremely thin appearance.
  • Bulimia nervosa: People with this condition overeat and then purge to avoid gaining weight. They may also abuse laxatives and diet pills.
  • Binge eating: People with this condition eat uncontrollably and don't purge.
  • Other specified feeding or eating disorder (OSFED): This condition was originally called “eating disorders not otherwise specified” (EDNOS).

The exact cause of eating disorders is unknown. But several factors can contribute to the disease. Eating disorders may begin in the teen and young adult years. These are ages when many people are focused on their self-image. The illness can also run in families. Some emotional disorders, like obsessive-compulsive disorder and depression, increase the risk for an eating disorder.

Eating disorders can have serious, life-threatening complications. So, it’s important to get help for these conditions. But before a doctor can treat an eating disorder, they have to diagnose the condition. Some people may deny a problem. But certain symptoms can show that someone may have an issue with food.

Doctors use physical and psychological evaluations to diagnose eating disorders. They’ll also make sure you meet the diagnostic criteria for an eating disorder. These criteria are outlined in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), published by the American Psychiatric Association (APA).

Physical evaluations

Physical exam

During a physical exam, your doctor will check your height, weight, and vital signs. Your doctor will also listen to your lungs and heart, since eating disorders can cause:

  • high or low blood pressure
  • slow breathing
  • slow pulse rates

Your doctor may examine your abdomen. They may also check your skin and hair for dryness, or look for brittle nails. And they may ask about any other possible problems, like a sore throat or intestinal issues. These can be complications of bulimia.

Laboratory tests

Eating disorders can damage the body and cause problems with vital organs. So, doctors may run lab tests, including:

  • a complete blood count
  • liver, kidney, and thyroid function tests
  • urinalysis

Your doctor may also order an X-ray to look for broken bones, which can be a sign of bone loss from anorexia or bulimia. And an electrocardiogram can check your heart irregularities. Your doctor may also examine your teeth for signs of decay. This is another symptom of an eating disorder.

Psychological evaluations

Doctors don’t diagnose eating disorders based on a physical exam. A psychological evaluation by a mental health doctor is also required.

Your mental health doctor will ask you questions about your eating habits. The goal is to understand your attitude toward food and eating. The doctor also needs to get an idea of how you perceive your body.

The questions can be personal, especially when talking about dieting, binging, purging, or extreme exercise habits. It's important to answer honestly so your doctor can make an accurate diagnosis and recommend a treatment plan.

Reviewing diagnostic criteria for eating disorders

To be diagnosed with an eating disorder, you must meet the criteria for a specific type of disorder. Symptoms of eating disorders vary depending on the type of eating disorder. They may include:

Anorexia nervosa

  • thin appearance
  • insomnia
  • extreme tiredness
  • dizziness or fainting spells
  • bluish nails
  • brittle hair and nails
  • constipation
  • dry skin
  • irregular heart rhythm

Bulimia nervosa

  • fear of gaining weight
  • extreme use of weight loss supplements
  • forced vomiting
  • extreme exercising
  • regularly using laxatives, diuretics, or enemas

Binge eating

  • eating unusually large portions of food
  • eating until uncomfortably full
  • insistence on eating alone
  • constantly dieting but not losing weight
  • depression and anxiety


In the United States, 20 million women and 10 million men have eating disorders. According to NEDA, they’ll develop disorders that include anorexia nervosa, bulimia nervosa, and binge eating disorder at some point in their lives.

Eating disorders are serious illnesses. They can lead to life-threatening complications like organ failure and death. But with a timely diagnosis, you can receive necessary treatment and live a long, healthy life.

Content licensed from:

Written by: Valencia Higuera
Medically reviewed on: Dec 05, 2016: Timothy J. Legg, PhD, CRNP

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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