Anorexia nervosa is one type of eating disorder.  It is also a psychological disorder or condition that goes beyond out-of-control dieting.  A person with anorexia initially begins dieting to lose weight.  Over time, the weight loss becomes a sign of mastery and control where the drive to become thinner is actually secondary to concerns about control and/or fears related to one’s body.  The individual enters a continuous endless cycle of restrictive eating often to a point close to starvation in order to fell a sense of control over their body.  This cycle becomes an obsession similar to any type of drug or substance addiction.