An eating disorder is to eat too much, or avoid eating, in a manner, which negatively affects both one's physical and mental health. Eating disorders are all encompassing. They affect every part of the person's life.

If you have an eating disorder, food, eating, exercise, body image is in the centre of your life.

Anorexia nervosa and bulimia nervosa are the most common eating disorders generally recognized by medical classification schemes with a significant diagnostic overlap between the two. There is a third type of eating disorder currently being investigated and defined - Binge Eating Disorder.

This is a chronic condition that occurs when an individual consumes huge amounts of food during a brief period of time and feels totally out of control and unable to stop their eating. It can lead to serious health conditions such as morbid obesity, diabetes, hypertension, and cardiovascular disease.

Source: http://www.wikipedia.com