A. Refusal to maintain body weight at or above a minimally normal weight for age and height, for example, weight loss leading to maintenance of body weight less than 85% of that expected or failure to make expected weight gain during period of growth, leading to body weight less than 85% of that expected.
B. fear of gaining weight or becoming fat, even though underweight.
C. Disturbance in the way one's body weight or shape is experienced, undue influence of body weight or shape on self evaluation, or denial of the seriousness of the current low body weight.
D. In postmenarcheal females, amenorrhea, i.e., the absence of at least 3 consecutive menstrual cycles. A woman having periods only while on hormone medication (e.g. estrogen) still qualifies as having amenorrhea.
The key feature to identifying someone with anorexia is a failure to maintain 85% of the normal body weight for someone of their height. This failure to maintain weight is due to a restriction of food intake, the use of laxatives so they don’t digest calories, or purging their stomach by forcing themselves to vomit.
Anorexia sufferers cannot control their desire to lose weight and restrict calories and are very upset about their disorder most of the time. However, when reducing calorie intake, anorexia sufferers often feel the best about themselves and even express the feeling of being starving as a positive and joyful experience. Anorexics are often obsessed with food and body image, and very often attempt to control themselves, their environment, and their eating, in order to relieve anxiety or distress.
Contrary to popular belief, binging and purging does not qualify as bulimic if body weight is below 85% of the normal body weight. In this case, it would be called anorexia nervosa – binging and purging type.
The exact cause of bulemia is not known, however there are some major risk factors including: