Symptoms vary, depending on the type of eating disorder. Anorexia nervosa, bulimia nervosa and binge-eating disorder are the most common eating disorders. Other eating disorders include rumination disorder and avoidant/restrictive food intake disorder.

Anorexia nervosa

Anorexia (an-o-REK-see-uh) nervosa — often simply called anorexia — is a potentially life-threatening eating disorder characterized by an abnormally low body weight, intense fear of gaining weight, and a distorted perception of weight or shape. People with anorexia use extreme efforts to control their weight and shape, which often significantly interferes with their health and life activities.

When you have anorexia, you excessively limit calories or use other methods to lose weight, such as excessive exercise, using laxatives or diet aids, or vomiting after eating. Efforts to reduce your weight, even when underweight, can cause severe health problems, sometimes to the point of deadly self-starvation.

Bulimia nervosa

Bulimia (boo-LEE-me-uh) nervosa — commonly called bulimia — is a serious, potentially life-threatening eating disorder. When you have bulimia, you have episodes of bingeing and purging that involve feeling a lack of control over your eating. Many people with bulimia also restrict their eating during the day, which often leads to more binge eating and purging.

During these episodes, you typically eat a large amount of food in a short time, and then try to rid yourself of the extra calories in an unhealthy way. Because of guilt, shame and an intense fear of weight gain from overeating, you may force vomiting or you may exercise too much or use other methods, such as laxatives, to get rid of the calories.

If you have bulimia, you're probably preoccupied with your weight and body shape, and may judge yourself severely and harshly for your self-perceived flaws. You may be at a normal weight or even a bit overweight.

Binge-eating disorder

When you have binge-eating disorder, you regularly eat too much food (binge) and feel a lack of control over your eating. You may eat quickly or eat more food than intended, even when you're not hungry, and you may continue eating even long after you're uncomfortably full.

After a binge, you may feel guilty, disgusted or ashamed by your behavior and the amount of food eaten. But you don't try to compensate for this behavior with excessive exercise or purging, as someone with bulimia or anorexia might. Embarrassment can lead to eating alone to hide your bingeing.

A new round of bingeing usually occurs at least once a week. You may be normal weight, overweight or obese.

Rumination disorder

Rumination disorder is repeatedly and persistently regurgitating food after eating, but it's not due to a medical condition or another eating disorder such as anorexia, bulimia or binge-eating disorder. Food is brought back up into the mouth without nausea or gagging, and regurgitation may not be intentional. Sometimes regurgitated food is rechewed and reswallowed or spit out.

The disorder may result in malnutrition if the food is spit out or if the person eats significantly less to prevent the behavior. The occurrence of rumination disorder may be more common in infancy or in people who have an intellectual disability.

Avoidant/restrictive food intake disorder

This disorder is characterized by failing to meet your minimum daily nutrition requirements because you don't have an interest in eating; you avoid food with certain sensory characteristics, such as color, texture, smell or taste; or you're concerned about the consequences of eating, such as fear of choking. Food is not avoided because of fear of gaining weight.

The disorder can result in significant weight loss or failure to gain weight in childhood, as well as nutritional deficiencies that can cause health problems.

The exact cause of eating disorders is unknown. As with other mental illnesses, there may be many causes, such as:

• Genetics and biology. Certain people may have genes that increase their risk of developing eating disorders. Biological factors, such as changes in brain chemicals, may play a role in eating disorders.
• Psychological and emotional health. People with eating disorders may have psychological and emotional problems that contribute to the disorder. They may have low self-esteem, perfectionism, impulsive behavior and troubled relationships.

Teenage girls and young women are more likely than teenage boys and young men to have anorexia or bulimia, but males can have eating disorders, too. Although eating disorders can occur across a broad age range, they often develop in the teens and early 20s.

Certain factors may increase the risk of developing an eating disorder, including:

• Family history. Eating disorders are significantly more likely to occur in people who have parents or siblings who've had an eating disorder.
• Other mental health disorders. People with an eating disorder often have a history of an anxiety disorder, depression or obsessive-compulsive disorder.
• Dieting and starvation. Dieting is a risk factor for developing an eating disorder. Starvation affects the brain and influences mood changes, rigidity in thinking, anxiety and reduction in appetite. There is strong evidence that many of the symptoms of an eating disorder are actually symptoms of starvation. Starvation and weight loss may change the way the brain works in vulnerable individuals, which may perpetuate restrictive eating behaviors and make it difficult to return to normal eating habits.
• Stress. Whether it's heading off to college, moving, landing a new job, or a family or relationship issue, change can bring stress, which may increase your risk of an eating disorder.

Eating disorders cause a wide variety of complications, some of them life-threatening. The more severe or long lasting the eating disorder, the more likely you are to experience serious complications, such as:

• Serious health problems
• Depression and anxiety
• Suicidal thoughts or behavior
• Problems with growth and development
• Social and relationship problems
• Substance use disorders
• Work and school issues
• Death