The Facts
Eating disorders have increased in frequency as a consequence of society's emphasis and preoccupation with thinness. Eating disorders are multi-factorial, with genetic, traumatic, and nutritional causes. In North America, anorexia nervosa and bulimia nervosa are the two most common eating disorders. They predominantly affect women.
Anorexia nervosa is a psychiatric condition in which people intentionally starve themselves because of a false belief that they are fat, or for fear of becoming obese. In reality, they are almost always underweight or of normal weight when the condition starts. It is estimated that more than 90% of all those diagnosed with anorexia nervosa are women, often from middle and upper socioeconomic backgrounds. This disorder usually starts in the years between adolescence and young adulthood, with the average age at onset of 14 years. Anorexia nervosa afflicts about 1 person out of 100,000 in the population at large, but the rate is believed to be higher among Caucasian adolescent girls, about 1 in 200.
Bulimia nervosa is an eating disorder characterized by uncontrolled or compulsive binge eating, usually followed by inappropriate ways of trying to get rid of the food. Most often, this involves purging by self-induced vomiting or abuse of laxatives, enemas, or diuretics. It's also sometimes called the binge-purge syndrome. Some people with bulimia don't purge, but will overeat (consuming as many as 20,000 calories at one time) and then compensate for binge-eating sessions with other behaviors such as fasting or over-exercising. A person with bulimia may secretly binge anywhere from twice a day to several times daily. In most cases, binge eating is followed by purging. A person with bulimia may use as many as 20 or more laxatives at a time.
Bulimia commonly appears in the latter part of adolescence, between the ages of 18 and 20, but it can develop at an earlier or later age. Like anorexia, bulimia predominantly affects young, Caucasian, middle- and upper-class women. The American Psychiatric Association estimates that between 0.5% and 3.7% of women experience anorexia and between 1.1% and 4.2% experience bulimia at some point in their lifetime. One difference between people with bulimia and anorexia nervosa is that people with bulminia are aware of their problems with food yet they don't feel in control of their condition.