Anorexics may lose as much as 15 to 20 pounds per month, according to Orgclinic.com. The amount of weight loss is dependent upon the person's body type, how much exercise he gets, and his overall nutritional intake.
When a body is starved of its nutrients, exercise becomes harder, Orgclinic.com goes on to explain. Also, when a body is starved, it turns to using its muscle tissue and body fat for nutrients. Anorexics lose muscle definition because the body has to eat away at itself in order to survive. As the body consumes the body fat and muscle tissue, weight loss slows, and body shutdown may eventually occur.
The speed of weight loss depends on the particular tactics used by the individual anorexic, according to Orgclinic.com. People with anorexia nervosa use various measures to drastically reduce food intake such as purging, taking laxatives and simply not eating.
Anorexics also tend to exercise excessively, says the Office on Woman's Health, a branch of the U.S. Department of Health and Human Services. The body responds to these actions by slowing the metabolism and breaking down the muscle tissues, among other system changes.
Anorexia is an eating disorder that can be fatal, according to the Office on Women's Health, but anorexics can get better with guidance from doctors, nutritionists and therapists.