If you find yourself having a strong fear of becoming fat even though you are underweight or have a normal weight, this might signal a problem. Anorexia Nervosa isa type of eating disorder that involves disturbed eating patterns and negative thinking related to food. This problem is more common in females than males. It often begins in adolescence and occurs in adulthood.In Anorexia Nervosa, a person might be so preoccupied with being slim that she/he might starve herself/himself to achieve weight loss. This could have severe consequences and, in women, lead to disturbance in menstrual cycle. The person might have a low body weightbut be unable to see the seriousness of the problem.