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What are Eating Disorders?

Eating disorders are behavioral conditions characterized by severe and persistent disturbance in eating behaviors and associated distressing thoughts and emotions. They can be very serious conditions affecting physical, psychological and social function. Types of eating disorders include anorexia nervosa, bulimia nervosa, binge eating disorder, avoidant restrictive food intake disorder, other specified feeding and eating disorder, pica and rumination disorder.

Taken together, eating disorders affect up to 5% of the population, most often develop in adolescence and young adulthood. Several, especially anorexia nervosa and bulimia nervosa are more common in women, but they can all occur at any age and affect any gender. Eating disorders are often associated with preoccupations with food, weight or shape or with anxiety about eating or the consequences of eating certain foods. Behaviors associated with eating disorders including restrictive eating or avoidance of certain foods, binge eating, purging by vomiting or laxative misuse or compulsive exercise. These behaviors can become driven in ways that appear similar to an addiction.

Eating disorders often co-occur with other psychiatric disorders most commonly, mood and anxiety disorders, obsessive-compulsive disorder, and alcohol and substance use disorders. Evidence suggests that genes and heritability play a part in why some people are at higher risk for an eating disorder, but these disorders can also afflict those with no family history of the condition. Treatment should address psychological, behavioral, nutritional and other medical complications. The latter can include consequences of malnutrition or of purging behaviors including, heart and gastrointestinal problems as well as other potentially fatal conditions. Ambivalence towards treatment, denial of a problem with eating and weight, or anxiety about changing eating patterns is not uncommon. With proper medical care, however, those with eating disorders can resume healthy eating habits, and recover their emotional and psychological health.

Types of Eating Disorders

Anorexia Nervosa

Anorexia nervosa is characterized by self-starvation and weight loss resulting in low weight for height and age. Anorexia has the highest mortality of any psychiatric diagnosis other than opioid use disorder and can be a very serious condition. Body mass index or BMI, a measure of weight for height, is typically under 18.5 in an adult individual with anorexia nervosa.

Dieting behavior in anorexia nervosa is driven by an intense fear of gaining weight or becoming fat. Although some individuals with anorexia will say they want and are trying to gain weight, their behavior is not consistent with this intent. For example, they may only eat small amounts of low-calorie foods and exercise excessively. Some persons with anorexia nervosa also intermittently binge eat and or purge by vomiting or laxative misuse.

There are two subtypes of anorexia nervosa:

  • Restricting type, in which individuals lose weight primarily by dieting, fasting or excessively exercising.
  • Binge-eating/purging type in which persons also engage in intermittent binge eating and/or purging behaviors.

Over time, some of the following symptoms may develop related to starvation or purging behaviors:

  • Menstrual periods cease
  • Dizziness or fainting from dehydration
  • Brittle hair/nails
  • Cold intolerance
  • muscle weakness and wasting
  • Heartburn and reflux (in those who vomit)
  • Severe constipation, bloating and fullness after meals
  • Stress fractures from compulsive exercise as well as bone loss resulting in osteopenia or osteoporosis (thinning of the bones)
  • Depression, irritability, anxiety, poor concentration and fatigue

Serious medical complications can be life threatening and include heart rhythm abnormalities especially in those patients who vomit or use laxatives, kidney problems or seizures.

Treatment for anorexia nervosa involves helping those affected normalize their eating and weight control behaviors and restore their weight. Medical evaluation and treatment of any co-occurring psychiatric or medical conditions is an important component of the treatment plan. The nutritional plan should focus on helping individuals counter anxiety about eating and practice consuming a wide and balanced range of foods of different calorie densities across regularly spaced meals. For adolescents, the and emerging adults, most effective treatments involve helping parents to support and monitor their child's meals. Addressing body dissatisfaction is also important but this often takes longer to correct than weight and eating behavior.

In the case of severe anorexia nervosa when outpatient treatment is not effective, admission to an inpatient or residential behavioral specialty program may be indicated. Most specialty programs are effective in restoring weight and normalizing eating behavior, although the risk of relapse in the first year following program discharge remains significant.

Bulimia Nervosa

Individuals with bulimia nervosa typically alternate dieting, or eating only low calorie “safe foods” with binge eating on “forbidden” high calorie foods. Binge eating is defined as eating a large amount of food in a short period of time associated with a sense of loss of control over what, or how much one is eating. Binge behavior is usually secretive and associated with feelings of shame or embarrassment. Binges may be very large and food is often consumed rapidly, beyond fullness to the point of nausea and discomfort.

Binges occur at least weekly and are typically followed by what are called "compensatory behaviors" to prevent weight gain. These can include fasting, vomiting, laxative misuse or compulsive exercise. As in anorexia nervosa, persons with bulimia nervosa are excessively preoccupied with thoughts of food, weight or shape which negatively affect, and disproportionately impact, their self-worth.

Individuals with bulimia nervosa can be slightly underweight, normal weight, overweight or even obese. If they are significantly underweight however, they are considered to have anorexia nervosa binge-eating/purging type not bulimia nervosa. Family members or friends may not know that a person has bulimia nervosa because they do not appear underweight and because their behaviors are hidden and may go unnoticed by those close to them. Possible signs that someone may have bulimia nervosa include:

  • Frequent trips to the bathroom right after meals
  • Large amounts of food disappearing or unexplained empty wrappers and food containers
  • Chronic sore throat
  • Swelling of the salivary glands in the cheeks
  • Dental decay resulting from erosion of tooth enamel by stomach acid
  • Heartburn and gastroesophageal reflux
  • Laxative or diet pill misuse
  • Recurrent unexplained diarrhea
  • Misuse of diuretics (water pills)
  • Feeling dizzy or fainting from excessive purging behaviors resulting in dehydration

Bulimia can lead to rare but potentially fatal complications including esophageal tears, gastric rupture, and dangerous cardiac arrhythmias. Medical monitoring in cases of severe bulimia nervosa is important to identify and treat any possible complications.

Outpatient cognitive behavioral therapy for bulimia nervosa is the treatment with the strongest evidence. It helps patients normalize their eating behavior and manage thoughts and feelings that perpetuate the disorder. Antidepressants (e.g. fluoxetine) can also be helpful in decreasing urges to binge and vomit. Eating disorder focused family based treatment which involves providing caregivers with information on how to assist an adolescent or young adult to normalize their eating pattern may also be helpful in the treatment of young people with bulimia nervosa.

Binge Eating Disorder

As with bulimia nervosa, people with binge eating disorder have episodes of binge eating in which they consume large quantities of food in a brief period, experience a sense of loss of control over their eating and are distressed by the binge behavior. Unlike people with bulimia nervosa however, they do not regularly use compensatory behaviors to get rid of the food by inducing vomiting, fasting, exercising or laxative misuse. Binge eating disorder can lead to serious health complications, including obesity, diabetes, hypertension and cardiovascular diseases.

The diagnosis of binge eating disorder requires frequent binges (at least once a week for three months), associated with a sense of lack of control and with three or more of the following features:

  • Eating more rapidly than normal.
  • Eating until uncomfortably full.
  • Eating large amounts of food when not feeling hungry.
  • Eating alone because of feeling embarrassed by how much one is eating.
  • Feeling disgusted with oneself, depressed or very guilty after a binge.

As with bulimia nervosa, the most effective treatment for binge eating disorder is either individual or group-based cognitive behavioral psychotherapy for binge eating. Interpersonal therapy has also been shown to be effective, as have several antidepressant medications and lisdexamfetamine.

Specified Feeding and Eating Disorder

This diagnostic category includes eating disorders or disturbances of eating behavior that cause distress and impair family, social or work function but do not fit the other categories listed here. In some cases, this is because the frequency of the behavior does not meet the diagnostic threshold (e.g., the frequency of binges in bulimia or binge eating disorder) or the weight criteria for the diagnosis of anorexia nervosa are not met.

An example of other specified feeding and eating disorder is "atypical anorexia nervosa". This category includes individuals who may have lost a lot of weight and whose behaviors and preoccupation with weight or shape concerns and fear of fatness is consistent with anorexia nervosa, but who are not yet considered underweight based on their BMI because their baseline weight was above average.

Since speed of weight loss is related to medical complications, individuals with atypical anorexia nervosa who lose a lot of weight rapidly by engaging in extreme weight control behaviors can be at high risk of medical complications, despite appearing normal or above average weight.

Avoidant Restrictive Food Intake Disorder (ARFID)

ARFID is a recently defined eating disorder that involves a disturbance in eating resulting in persistent failure to meet nutritional needs and extreme picky eating. In ARFID, food avoidance or a limited food repertoire can be due to one or more of the following:

  • Low appetite and lack of interest in eating or food.
  • Extreme food avoidance based on sensory characteristics of foods e.g. texture, appearance, color, smell.
  • Anxiety or concern about consequences of eating, such as fear of choking, nausea, vomiting, constipation, an allergic reaction, etc. The disorder may develop in response to a significant negative event such as an episode of choking or food poisoning followed by the avoidance of an increasing variety of foods.

The diagnosis of ARFID requires that difficulties with eating are associated with one or more of the following:

  • Significant weight loss (or failure to achieve expected weight gain in children).
  • Significant nutritional deficiency.
  • The need to rely on a feeding tube or oral nutritional supplements to maintain sufficient nutrition intake.
  • Interference with social functioning (such as inability to eat with others).

The impact on physical and psychological health and degree of malnutrition can be similar to that seen in people with anorexia nervosa. However, people with ARFID do not have excessive concerns about their body weight or shape and the disorder is distinct from anorexia nervosa or bulimia nervosa. Also, while individuals with autism spectrum disorder often have rigid eating behaviors and sensory sensitivities, these do not necessarily lead to the level of impairment required for a diagnosis of avoidant/restrictive food intake disorder.

ARFID does not include food restriction related to lack of availability of food; normal dieting; cultural practices, such as religious fasting; or developmentally normal behaviors, such as toddlers who are picky eaters.

Food avoidance or restriction commonly develops in infancy or early childhood and may continue in adulthood. It can however start at any age. Regardless of the age of the person affected, ARFID can impact families, causing increased stress at mealtimes and in other social eating situations.

Treatment for ARFID involves an individualized plan and may involve several specialists including a mental health professional, a registered dietitian nutritionist, and others.


Pica is an eating disorder in which a person repeatedly eats things that are not food with no nutritional value. The behavior persists over at least one month and is severe enough to warrant clinical attention.

Typical substances ingested vary with age and availability and might include paper, paint chips, soap, cloth, hair, string, chalk, metal, pebbles, charcoal or coal, or clay. Individuals with pica do not typically have an aversion to food in general.

The behavior is inappropriate to the developmental level of the individual and is not part of a culturally supported practice. Pica may first occur in childhood, adolescence, or adulthood, although childhood onset is most common. It is not diagnosed in children under age 2. Putting small objects into their mouth is a normal part of development for children under 2. Pica often occurs along with autism spectrum disorder and intellectual disability, but can occur in otherwise typically developing children.

A person diagnosed with pica is at risk for potential intestinal blockages or toxic effects of substances consumed (e.g. lead in paint chips).

Treatment for pica involves testing for nutritional deficiencies and addressing them if needed. Behavior interventions used to treat pica may include redirecting the individual from the nonfood items and rewarding them for setting aside or avoiding nonfood items.

Rumination Disorder

Rumination disorder involves the repeated regurgitation and re-chewing of food after eating whereby swallowed food is brought back up into the mouth voluntarily and is re-chewed and re-swallowed or spat out. Rumination disorder can occur in infancy, childhood and adolescence or in adulthood. To meet the diagnosis the behavior must:

  • Occurs repeatedly over at least a 1-month period
  • Not be due to a gastrointestinal or medical problem
  • Not occur as part of one of the other behavioral eating disorders listed above
  • Rumination can also occur in other mental disorders (e.g. intellectual disability) however the degree must be severe enough to warrant separate clinical attention for the diagnosis to be made.

Physician Review

Angela Guarda, M.D.

February 2023

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