Could you tell me what are main leads to of anorexia?

Genes & environment: Anorexia nervosa is a highly heritable condition of unknown cause. It seems not to be enough just to inherit the vulnerability to it, something in the environment seem to allow it to develop. But what that "something" is is almost entirely unknown. It is probably not just "stress", for example. Research into season of birth, obstetric complications, bad effects of dieting, etc are ongoing.