The main symptom of the eating disorder, bulimia nervosa, is repetitive binge eating. During a binge, a person eats large quantities of food in a relatively short time, regardless of hunger. Binge eating is defined only in part by food quantity. A more important feature is the person's state of mind: During a binge, the person with bulimia feels out of control of the eating and cannot stop it.
By definition, bulimia is divided into a "purging" and "nonpurging" type, depending on what strategies the individual may use to try to control weight. Purging is vomiting self-induced immediately after a binge. In the nonpurging type of bulimia, a person may abuse laxatives, suppositories, enemas or diuretics, may go on an extended fast or start a period of strenuous exercise.
There is significant overlap between bulimia nervosa and anorexia nervosa, since those with bulimia may restrict food intake (a characteristic of anorexia) and people with anorexia may binge and purge. In both disorders, a person may be preoccupied with weight and be very self-conscious about body size and shape.
The overwhelming majority of people with bulimia are female (85-90 percent) and the disorder usually begins between ages 15 and 20. The condition affects up to 4 percent of women at some point in life. When men have the disorder, it is usually the nonpurging type.
People with bulimia can eat huge quantities of food, sometimes up to 20,000 calories at a time. Binge foods tend to be "comfort" foods that are sweet, salty, soft or smooth, and generally high in calories. Examples are ice cream, cake and pastries. People with bulimia may binge a few times a week or as frequently as several times a day. Although people with bulimia fear becoming fat, and some are severely underweight or overweight, most are of normal weight or only slightly overweight.
Like anorexia, bulimia is unhealthy for the body. Purging can cause dehydration. The strong acids in stomach contents eat away at the layer of protective tooth enamel, making teeth much more vulnerable to decay. Laxative use can cause chronic gastrointestinal problems. At its most destructive, bulimic behavior can lead to problems with heart function. Rarely, it can cause death.
People with bulimia often feel ashamed of their binging and purging behaviors, so they may act secretly. They often have other problems with impulse control (such as addictions) and other mental health problems, including depression, anxiety, panic, or social phobia.
The specific biological cause for bulimia nervosa is not known, but it is presumed to have a genetic (inherited) component. The disorder does run in families. Most experts believe that, in bulimia, the brain areas that regulate appetite do not function properly.