Anorexia nervosa is a very common type of eating disorder. The main feature of the disease is self-restricting behavior on food, which causes sufferers to follow drastic diets to lose weight. Anorexia includes a phobia of being fat, and people affected by the disease develop food obsessions. Although the actual causes of anorexia are not clear, the disease appears to have a pronounced psychological character. Anorexia occurs due to emotional stress and mental instability, and the majority of those affected have low self-esteem and poor self-image.