is literary loss of appetite due to many reasons. The most common type of anorexia is postprandial anorexia and its simply satiation of food consumption and it happens a lot in normal people. Also there are many other reasons for developing anorexia which can be dangerous and harmful. The most common type of harmful anorexia is caused by anorexia nervosa.
Anorexia nervosa is characterized by eating disorder (often chronic) usually occurring in females between 15 and 30 years due to mental problems. Although less commonly it can also affect males and older females. These mental problems oftenly include tendency to go on strict diet in purpose of reducing body fat. It usually affects actors, models, athletes and the other kind of famous individuals. Also teens are very liable of developing anorexia nervosa.
Symptoms of anorexia nervosa are miscellaneous. People developing this disease usually reduce food intake dramatically and they have very strong criterions about their body fat percentage. Also sometimes they develop very strange eating habits such as refusing to eat in company, reducing amount of food in other people's meals (considering it normally),

or cutting food into small pieces before consummation. In other words food becomes obsession in their lives. People with anorexia nervosa are very liable of developing depression and obsessive-compulsive disorder. Also they usually have higher levels of cortisol in blood (brain hormone released as result of stress)
Eating disorders can also be provoked in stressful situations and can have genetic origins.
The starvation will lead to strength loss that can be cause of many other disorders such as heart or brain damage, bones problem due to calcium loss and in the worst cases death can also occur due to overmuch starvation. Cause of that anorexia nervosa has very high level of mortality (about 6 percent of patients).
Treatments usually consist of individual or grout therapies, although sometimes hospitalization is necessary in purpose of weight restoration.