What are eating disorders?

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A group of conditions characterized by disordered eating patterns, preoccupation with body size and weight, and distorted body image. Eating disorders can cause serious medical complications and even death. The causes of eating disorders are complex and involve biological, psychological, and societal factors.
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Causes and Symptoms

Identified eating disorders include anorexia nervosa, bulimia nervosa, and binge-eating disorder. These disorders are not always distinct, and many individuals exhibit symptoms of more than one. Their prevalence has increased during the past several decades. Anorexia nervosa and bulimia nervosa predominantly affect adolescent and young adult females. However, they can also occur in males and the elderly, and binge-eating disorder occurs more frequently in males. Approximately 4 percent of females have eating disorders, although the number of those who do not meet the full criteria for diagnosing any specific disorder is much higher. There is an approximately nine to one ratio of females to males with eating disorders. The incidence of eating disorders in males is rising, however, and they are most commonly associated with sports (such as wrestling), bodybuilding, and the performing arts (such as dance). The disorders can be chronic and recur across the life span of an individual. Recognition of eating disorders in the elderly has increased, as have the negative health affects of the conditions on this population.

Anorexia nervosa is characterized by refusal to maintain normal body weight (less than 85 percent of expected weight), extreme fear of becoming fat, and relentless pursuit of thinness. Individuals with anorexia nervosa have a distorted perception of body weight and size and consider themselves to be overweight even when the opposite is true. Their view of themselves is heavily dependent on factors such as their level of adherence to a restrictive diet or the fit of their clothes. They often deny the negative aspects of low weight even in the face of serious health problems.

Two types of anorexia nervosa have been identified: the restricting type, involving dieting, fasting, or skipping meals, but not bingeing/purging; and the binge-eating/purging type, involving binge eating and purging (self-induced vomiting or misusing laxatives, enemas, or diuretics). The latter type is primarily distinguished from bulimia nervosa by refusal to maintain 85 percent of normal body weight. Dieting regimens may be severe, with intake reduced to between three hundred and six hundred kilocalories (Calories) per day and strict habits regarding food selection and eating.

Individuals with anorexia nervosa commonly display a set of personality and behavioral characteristics including being goal driven, perfectionistic, and overtly competent at school or work. Underlying these tendencies is often a lack of confidence and low sense of self-worth. As dieting increases, individuals may become depressed and fatigued, causing school or work to suffer and further eroding self-perception. Rigid “all or nothing” thinking influences the severity of dieting. Thus, anorexic people might believe that if they permit themselves even one lapse in dieting, then they will become obese. As starvation develops, focus on food and weight increases, and behaviors such as hoarding food, gazing in mirrors, or seeking reassurance about appearance may be observed. Significant energy is expended to keep secret the severity of weight loss efforts. Consequently, exercise may be conducted privately, family meals and public eating avoided, or food disposed of surreptitiously. In some cases, anorexia nervosa is not discovered until after a health problem has developed consequent to malnutrition.

A number of serious health problems stemming from starvation and malnutrition are seen in people with anorexia nervosa. Among the most serious are those associated with cardiac functioning, including cardiomyopathy, arrhythmias, and altered heart rates. In rare cases, sudden death can occur as a result of irregular heart muscle contractions. Other health problems caused by anorexia nervosa involve the gastrointestinal system (bloating and constipation), the reproductive system (amenorrhea, hormonal abnormalities, and infertility), and the skeletal system (osteoporosis and osteopenia). Additional complications include lowered metabolism, cold intolerance, weakness, loss of muscle mass, low body temperature, and growth suppression. While elderly individuals with anorexia nervosa may not exhibit a drive for thinness, behaviors such as food refusal, the hoarding or hiding of food, and distorted body image are often observed. The health effects of anorexia nervosa in this population are significant and worsen coexisting illnesses, sometimes hastening death. A very serious condition known as the “female athlete triad” is a combination of factors involving athletic training: disordered eating, amenorrhea, and osteoporosis. Permanent damage to bone strength can result from this condition. Despite the numerous medical problems caused by anorexia nervosa, many with the disorder appear superficially healthy even after significant weight loss.

Bulimia nervosa is characterized by recurrent episodes of binge eating followed by purging or other inappropriate efforts to avoid weight gain. The episodes are accompanied by feelings of being out of control and subsequent self-disgust, guilt, and depression. Bingeing involves eating over a limited period of time an amount of food that is markedly larger than most people would under similar circumstances. Caloric intake during binges may range from two thousand to ten thousand. Social interruption, fear of discovery, or physical discomfort (nausea or abdominal pain) typically terminates the binge episode. The binge-purge cycle may occur several times per day, with considerable effort directed toward keeping the episodes secret. Typically, bulimics recognize that their behavior is abnormal and desire to change (as opposed to those with anorexia nervosa). The disorder is divided into two types. The purging type involves self-induced vomiting or laxative, diuretic, or enema misuse as methods to avoid weight gain. The nonpurging type involves fasting or excessive exercise to prevent weight gain.

Self-induced vomiting is the most frequent method of purging and is typically accomplished by initiating the gag reflex by placing fingers down the throat. Over time, many bulimics are able to vomit reflexively without the need to use their fingers. Though employed less frequently as the sole methods of purging, laxatives, enemas, and rarely diuretics may be used in conjunction with vomiting. Abuse of laxatives is more common among the elderly.

Individuals with nonpurging bulimia nervosa, especially males, engage in hours of exercise every day or fast following bingeing. Typically, the fast is broken by another binge episode and the cycle continues.

Those with bulimia nervosa place strong emphasis on appearance, and their mood and view of themselves are highly dependent on their weight and body shape. Most are at a normal weight, but some are underweight or overweight. Often bulimia nervosa is initiated by a restrictive diet that appears to cause many of the unusual behaviors and thinking patterns associated with anorexia nervosa, such as secretive behavior, food hoarding, and extreme focus on food and eating. There may be signs of depression and anxiety as well as compulsive behavior. As opposed to anorexia nervosa, those with bulimia nervosa are more likely to be interested in social relations and to worry more about how others perceive them. Some engage in impulsive behaviors such as substance abuse or shoplifting.

Serious medical complications can result from bulimia nervosa. Chronic vomiting or laxative abuse and consequent loss of body fluids may cause dizziness, cardiac abnormalities, dehydration, and weakness. Tooth decay caused by repeated exposure to gastric acids from vomiting may occur. Erosion or tearing of the esophagus can result from chronic vomiting. Bingeing is associated with a variety of gastrointestinal disturbances including bloating, diarrhea, and constipation.

Binge-eating disorder is a relatively newly identified condition, and less is known about it. The disorder is similar to bulimia nervosa but does not involve efforts to avoid weight gain (such as purging). Individuals with the disorder regularly engage in binges lasting up to several hours, during which from two thousand to ten thousand Calories may be consumed. Eating during binges is typically at a rapid pace and continues in spite of feeling discomfort or pain. Bingeing may occur when an individual is not very hungry, after attempting to keep a strict diet, or as a means to reduce stress. It is usually done in private and kept secret. Feeling out of control during binges is common, followed by feelings of self-disgust and shame. Preoccupation with food and unusual food-related behaviors (such as hiding food) are common. Individuals with binge-eating disorder are typically overweight and unhappy with their body shape and size. General mood and self-perception may be dependent on their weight and size. Depression and anxiety are common coexisting conditions. Distorted body image is less likely than with anorexia nervosa and bulimia nervosa. The health problems related to obesity are seen in those with binge-eating disorder. They include high blood pressure, diabetes, high cholesterol, and heart disease. Gastrointestinal problems may also result from bingeing.

The precise causes of eating disorders are unknown; however, a number of factors involving biological, psychological, and social variables have been identified as contributing to the conditions. The primary biological influences on all eating disorders are related to hunger and starvation. Research indicates that in healthy individuals, severe dieting produces moodiness, irritability, depression, food obsessions, social isolation, and apathy. These symptoms are also found in eating disorders and become more pronounced as starvation emerges. Thus, anorexia nervosa, bulimia nervosa, or binge-eating disorder may develop after food deprivation has occurred as a result of purposeful dieting in order to lose weight or enhance athletic performance, or consequent to food restriction resulting from illness (especially in the elderly) or stress. Hunger resulting from restrictive dieting is the major stimulus for bingeing. Because a majority of those who diet do not develop eating disorders, there is likely some as yet unidentified biological or genetic predisposition in some individuals. Biological abnormalities associated with the hypothalamus and thyroid gland have been identified in some individuals with anorexia nervosa, while other research points to neurochemical or hormonal imbalances. In the elderly, medications, coexisting health problems, and even poorly fitting dentures may initiate restricted eating, leading to anorexia nervosa. Irregular levels of the neurotransmitter serotonin may influence bingeing in bulimia nervosa and binge-eating disorder since it is associated with triggering signals of satiety to the brain. Knowledge of the causes of binge-eating disorder is limited; however, as with bulimia nervosa, there often is a history of being overweight or obese prior to developing the disorder.

A number of psychological factors have been identified as causing eating disorders. Most of these are not mutually exclusive, and none has been universally accepted as the primary causative factor for the conditions. Factors proposed to account for anorexia nervosa include phobic responses to food and weight gain, conflicted feelings over adolescent development and sexual maturity, and reactions to feelings of personal ineffectiveness by “controlling” hunger and the body. Faulty thinking, known as cognitive distortions, may cause misperceptions in body image and undue emphasis on the importance of appearance. Powerful needs to demonstrate self-discipline and to develop feelings of uniqueness and independence may also contribute to anorexia nervosa. Individuals with bulimia nervosa often exhibit mood fluctuations as well as impulsive behaviors. Bulimia nervosa is thought by some to be a variant of obsessive-compulsive disorder (OCD) in which bingeing results from irresistible urges to eat and purging is engaged in to alleviate overwhelming anxiety. Fewer psychological causes have been identified in binge-eating disorder. Some research suggests that characteristics seen in bulimia nervosa such as impulsivity and mood changes are also associated with this disorder. Depression, especially in the elderly population, appears to play a role in all eating disorders. Middle-aged and elderly individuals may employ behaviors such as extreme dieting, bingeing, and purging to reduce anxiety or to exert control in their lives.

Societal factors appear to also contribute to eating disorders. Popular media increasingly promotes physical appearance, and thinness is held up as the ideal body type. Since the 1950’s, there have been steady decreases in the weights of influential persons such as actors, fashion models, and musicians. Many popular role models for females and males are underweight. Significant social approval is often associated with weight loss and disapproval with weight gain. Thus, females and males may feel pressured to attain an unhealthy weight or unrealistic body shape. A number of Web sites are devoted to promoting anorexia nervosa and bulimia nervosa as a means of personal choice and self-expression and minimizing the medical and psychological damage caused by these disorders. No reliable family characteristics have been conclusively associated with eating disorders; however, some families appear to have higher than usual levels of depression, difficulties in communication, conflict, and focus on weight and appearance.

Treatment and Therapy

Treatment of eating disorders incorporates medical, behavioral, and psychological interventions. Typically, those with anorexia nervosa believe that their diet is justified, and resistance to treatment is the norm. Males may be especially resistant. Weight restoration is the central focus of initial treatment. Hospitalization is recommended for persons with more serious medical complications or who have less than 75 percent of expected weight. During hospitalization, daily monitoring of weight and caloric intake occurs, as well as any other necessary medical management. Behavioral therapy is employed to facilitate eating habits, and privileges such as social activity or family visits are made dependent upon increased eating and daily weight gains. Individual and family therapy are introduced as malnutrition eases and irritability, depression, and preoccupation with diet diminishes. Lengths of hospital stays vary from weeks to months depending on severity of illness and treatment progress.

Outpatient treatment may be recommended with individuals who have less severe medical complications, who are motivated to cooperate with treatment, and who have families that can independently monitor diet and health status. Weight restoration is facilitated by supervision of caloric intake and regular measurements as well as behavioral therapy techniques. Individual therapy focuses on altering cognitive distortions and assumptions about diet, weight, and body image and developing more effective means of dealing with stress. Family therapy aims to improve communication patterns, eating habits, and supportive behaviors.

No medications have been identified as effective agents in treating the core symptoms of anorexia nervosa. Medications that promote hunger may be used during the initial stages of treatment to facilitate eating. Also, medications to treat coexisting conditions such as depression and anxiety are often employed in the treatment regimen.

Most patients with bulimia nervosa do not require hospitalization unless medical complications are severe. Outpatient treatment involves individual psychotherapy, family therapy, and pharmacotherapy. Individual psychotherapy addresses cognitive distortions involving appearance and body image as well as behaviors, thoughts, and emotions that lead to binge episodes. Skills for problem solving and stress reduction are also taught. Treatment methods used for obsessive-compulsive disorder may also be employed, involving exposure to stimuli that usually trigger binge-purge behaviors while preventing them from occurring. Family therapy for bulimia nervosa aims at strengthening support and communication and developing healthy eating habits. With adolescents, impulsive behaviors associated with bulimia nervosa may be addressed by helping parents develop more effective methods of discipline and behavior management.

Antidepressant medications that regulate the neurotransmitter serotonin have been found to reduce bingeing, improve mood, and lesson preoccupation with weight and size. These same medications are useful in treating depression and anxiety, which are also commonly seen in those with bulimia nervosa.

Treatment of binge-eating disorder is similar to that of bulimia nervosa. Psychotherapy aims toward identifying and altering behaviors and feelings that lead to bingeing and developing effective methods of dealing with stress. Group therapy and weight loss programs with medical management may also be utilized. Antidepressants have also been found effective with binge-eating disorder.

Perspective and Prospects

Behaviors associated with eating disorders have been identified in the earliest writings of Western civilization, including those by the ancient Greeks and early Christians. Formal identification of eating disorders as medical illnesses occurred in the nineteenth century when case studies were first recorded. Treatment methods at that time were limited and often involved “mental hygiene” measures such as rest, fresh air, and cold or hot baths.

In the early to mid-twentieth century, psychological theories influenced by Sigmund Freud, an Austrian psychiatrist, dominated treatment methods for eating disorders. These conditions were viewed as resulting from early childhood experiences that caused problems with psychological and sexual development. Treatment involved psychoanalysis, a form of psychotherapy, often lasting several years. Limited evidence for the success of this approach caused its decline in use.

More recent and successful treatment approaches involve cognitive and behavioral therapy that aims to alter thinking and behavior contributing to eating disorders. Medications have increasingly been used in treating eating disorders since the 1980s. Identifying biological causes of the conditions and refining pharmacotherapy may offer the best hope for improving treatment in the future.

Eating disorders were once thought to occur exclusively among young Caucasian females from middle- and upper-class families. Consequently, research into the disorders has historically focused on this population. Increased awareness of the illnesses has revealed that they occur in all socioeconomic classes and races, as well as in males and the elderly. Additional research into these groups is needed.

Awareness of eating disorders and their dangers has expanded among the general public since the 1970s. Nevertheless, rates of these disorders are rising. The media publicizes celebrities’ struggles with these conditions, which may glamorize the illnesses even when negative aspects are reported. Establishing healthy eating habits and identifying potential problems early constitute the current focus of prevention efforts in medicine and education.


American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders: DSM-IV-TR. 5th ed. Arlington, Va.: American Psychiatric Publishing, 2013.

"Anorexia Nervosa." MedlinePlus, February 13, 2012.

Duyff, Roberta Larson, ed. 365 Days of Healthy Eating from the American Dietetic Association. Hoboken, N.J.: John Wiley & Sons, 2006.

McCoy, Krisha. "Binge Eating Disorder." Health Library, March 15, 2013.

National Association of Anorexia Nervosa and Associated Disorders. http://www.anad.org.

Parker, James M., and Philip M. Parker, eds. The 2002 Official Patient’s Sourcebook on Binge Eating Disorder. San Diego, Calif.: Icon Health, 2002.

Paterson, Anna. Fit to Die: Men and Eating Disorders. Thousand Oaks, Calif.: Sage, 2004.

Sackler, Ira M., and Marc A. Zimmer. Dying to Be Thin: Understanding and Defeating Anorexia Nervosa and Bulimia—A Practical, Lifesaving Guide. New York: Warner Books, 2001.

Thompson, Ron A., and Roberta Trattner Sherman. Helping Athletes with Eating Disorders. Champaign, Ill.: Human Kinetics, 1993.

Wood, Debra. "Bulimia Nervosa." Health Library, September 10, 2012.