The reason for conditions like anorexia nervosa is not known. It could be based on some misbelieves the patients have, that they would be more happier and successful if they remain slim and have an ideal figure. Stressful events are likely to increase the risk of eating disorders. These may range from major developments such as family conflict, a change in school or a family move, the loss of a boy friend or girl friend or a serious illness. Another hypothesis is that anorexia nervosa is a rejection of female sexuality brought on by the physical development associated with puberty. Life style and culture can also influence the occurrence of this disease. Moreover television, magazine and news paper messages bombard women and girls with advise on exercise more and eat less in order to lose weight more quickly and get an ideal shape. Several biological factors including genetic and some other hormones, may contribute the onset of this disorder. People in certain professions, such as modeling and ballet dancing, are especially at risk. A girl is in a higher risk of developing anorexia if she has a sibling with the same disease. Behavioral and environmental influences may also play a role. Depression is also a cause for anorexia.

It is claimed that there is a link between diabetes and developing an eating disorder especially anorexia nervosa. A person with diabetes is usually advised to control their food in order to control diabetes.