Anorexia Nervosa is a form of under nutrition caused by nervous and / or psychological factors. Typically, it is an eating disorder of adolescent girls, but occasionally it occurs in older females, younger children and males. Anorexia Nervosa patients are pre-occupied with food. They collect and read books and magazine articles relating to food, dieting and body weight. They have a better knowledge of nutrition than the general public. People with Anorexia Nervosa are determined to control the amounts of food they eat.

Their meal will contain foods, which are very low in fat and are mainly full of water, egg: lettuce, carrot sticks, celery and apples. The eating disorders, such as anorexia nervosa and bulimia nervosa, are recognized as types of psychiatric illnesses and disorders. Associated physical characteristics include excessive physical activity, denial of hunger in the face of starvation, academic success, asexual behavior, and a history of extreme weight loss methods. Psychiatric characteristics include excessive dependency needs, developmental immaturity, behavior favoring isolation, obsessive-compulsive behavior, and constriction of affect. Anorexia nervosa is thought to result from psychological, stresses involving sexual development at puberty.

There is also a high level of anxiety in patients who develop eating disorders such as anorexia nervosa. Anorexia Nervosa is a psychological disease that causes a patient to restrict food drastically or not eat food at all. It is carelessly called a ‘ slimmers disease'; actually it is self-imposed starvation to lose weight. Classic anorexics believe they are heading towards the mythical ‘ perfect' body as demanded by society, and they believe that by controlling their bodies they are controlling their lives. For the most part anorexia is a disease, which forms a pathological fear of becoming fat in the victim's head. This in a sense may not have been a threatening disease in itself if the anorexic did not also have a distorted body image.

Also with the ever-friendly ‘ waif' look, models with 20″ waists only encourage the anorexic, making her feel her extreme diets are much more acceptable. No one knows exactly what causes anorexia considering that it's psychological but many have theories on about what may influence it. Children at very early ages learn the importance of thinness in society. They are frequently exposed to the media image of a ‘ perfect' body and are also affected by their parent's infatuation with diets and exercises. A study held by the Children's hospital Medical Center (US) revealed that 39% of grade 3 girls and 29% of grade three boys said they had tried to diet. Children have been discovered to experience some sort of eating disorder earlier than the age of 10.

In summary, the exact cause of anorexia nervosa is not known. The disease is thought to arise from many factors, including physiologic and psychological. Pressures in today's society to be thin and the media's portrayal of thinness have been thought to play some role with this eating disorder. Often times, the start of the eating disorder is seen with separation from home or loss of a loved one. Family problems and emotional problems may play a role.

Eating disorders have also been viewed as a person's way to cope with one's changing body during puberty.