The Medical Minute: Eating disorders -- you can be too thin

March 01, 2006

By John Messmer
Penn State Family and Community Medicine
Penn State Milton S. Hershey Medical Center
Penn State College of Medicine

In a society in which two-thirds of its citizens are either overweight or obese, with so many social functions centered on a meal and with the proliferation of high-calorie snacks and fast-food restaurants, it is hard to understand that a significant segment of the population is not just thin, but dangerously underweight.

Even with popular magazines telling women to love their bodies, there remains a not-so-subtle message that thinner is better. Gymnasts, dancers and skaters have even more pressure to be thin. Dieting is one thing, but in as many as 10 million girls and women and as many as one million boys and men, weight is a true obsession occupying most of the affected person's day.

Eating disorders fall into three general classes: anorexia nervosa, bulimia nervosa and binge-eating disorder. There very likely is a genetic tendency and a chemical basis for the problem. It is not clear whether the problem is part of a larger group of psychological disorders or a distinct problem. Poor self-image, depression and anxiety are components of the underlying pathology, and cultural influences may cause affected individuals to focus on body weight as the target of their obsession.

It's not clear what turns a desire to lose weight into a disease with a 1-in-200 mortality rate. There often are personal and social issues such as low self-esteem, depression or anxiety, a history of teasing about weight or outright abuse -- things the person can not easily control. Body weight becomes the one thing the affected person can control. Most people with an eating disorder are Caucasian, but it's not certain if this is cultural or genetic. In addition, 90 percent of those with eating disorders are females between the ages of 12 and 25.

Anorexia nervosa

Anorexia nervosa is more than simply wanting to be very thin. Anorexics are actually afraid of being fat. Up to about 3 percent of women suffer from anorexia nervosa in their lifetimes. Fortunately, most recover.

Despite being dangerously thin, they see themselves as too fat. Most will vehemently resist gaining any weight and many stay seriously underweight. Anorexics are compulsive in their undereating, picking out only certain foods they will eat but avoiding regular meals. They often will exercise to excess trying to overcome the few calories they allow themselves to have. Many will induce vomiting and abuse laxatives.

Anorexia should be suspected in a girl or woman (it does occur in males, but much less often) who is clearly underweight and denies it. She may wear layers of clothing to hide her extreme thinness and will be very concerned about how much and what she eats. She has probably stopped menstruating and may have more illness and dental disease than previously. Her body temperature may be lower than normal.

Bulimia nervosa

Up to 4 percent of women experience bulimia during their lifetimes. In contrast to anorexics, bulimics eat and are rarely underweight; they may even be a little above normal weight. Bulimic women eat in binges. They consume an excessive amount of food in a short time, then feel compelled to compensate because of feelings of intense dissatisfaction with their bodies. Binging typically is done in secret. They will follow binges with purging: vomiting, laxatives, enemas, diuretics (water pills) and other medications and intense exercise to compensate. The need to purge is a compulsion and is accompanied by shame and disgust, but it is followed by a sense of relief. This may happen in cycles of two or three times a week. Although they are not usually underweight, bulimics still can suffer metabolic problems from the purging.

Binge eating

Binge eating is similar to bulimia but without the purging. Affected people compulsively overeat, often alone and in private. Eating is done quickly and without regard to hunger or feeling full. This recurrent binge eating causes shame and guilt and is as common in men as in women. Binge eaters are overweight and have increased risk of Type 2 diabetes, high cholesterol and gall bladder disease.


The first goal of anorexia treatment is to restore health. Because they fear weight gain, hospitalization and treatment by a multidisciplinary team of specialists in eating disorders may be required. Individual and family psychotherapy usually are included to help the anorexic learn to eat properly and accept food in a normal fashion. Ongoing support may be needed for years.

Bulimia treatment is aimed at eliminating the abnormal behaviors of binging and purging, usually through psychotherapy. Antidepressants also may be used; Prozac has shown benefit in bulimia.

Only recently has binge eating been considered separately as an eating disorder, so the best approach to treatment is not yet known. Psychotherapy is the basis for treatment with the goal of helping the person overcome the desire to eat compulsively.

Help is available for patients with an eating disorder and their families. For more information, go to or or online.

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Last Updated March 19, 2009