The DSM V will probably include four categories of eating disorders, anorexia nervosa, bulimia nervosa, binge eating disorder and eating disorder not otherwise specified. The lifetime prevalence is about 5%. Cultural, social and interpersonal elements can trigger the onset and changes in neural networks can sustain the illness. Brain based explanatory models have been developed which include an imbalance between top down control and hedonic and homeostatic elements. The longer the duration of untreated illness the harder it is to reverse the illness as a variety of maintaining factors develop. CBT remains the treatment of choice for bulimia nervosa but there is more uncertainty about treatment for anorexia nervosa although treatment with a focus on the interpersonal elements is of value