There is a difference!
I often hear people say that they have had anorexia and then developed bulimia. It can be difficult to understand what the difference is and why the difference is important. The difference is important for treatment as bulimia and anorexia are very different disorders and need to be treated as such..
Bulimia nervosa is more prevalent than anorexia nervosa; according to the DSM-IV bulimia has a prevalence of 1-3% in adolescent and young adult females (about 10x the rate found in males). The prevalence of anorexia nervosa is 0.5-1.0%, again according to the DSM-IV and anorexia affects more males in comparison to bulimia.
Patients with bulimia nervosa tend to be of normal body weight or even higher than normal body weight. Their illness is characterized by episodes of bingeing (eating large amounts of food within a short period of time) followed by compensatory behaviors, typically vomiting. Patients with bulimia nervosa may occasionally fast for a day or two, but do not have the characteristic long term weight suppression of those with anorexia nervosa. For this reason the issue of malnourishment is not quite as critical as the anorexic with a BMI of below 17. Such low body weight can open the door for a whole host of long term problems and be very life endangering.
~Tabitha