Anorexia nervosa (AN) is a life-threatening condition with the highest mortality rate of all psychiatric disorders. The core physiological features of ANare the extreme overvaluation of shape and weight. Severe AN causes cardiovascular complications and majorly refeeding syndrome. The prominent features of refeeding syndrome include severe hypophosphatemia, hypokalemia and hypomagnesia, and other fluid imbalance abnormalities, vitamin deficiencies, volume overload, and edema. Most cases are brought to clinical attention only when there are severe somatic complaints. According to the Global Leadership Initiative on Malnutrition (GLIM) classification, the patients with AN present chronic disease-related malnutrition without inflammation with different degrees of severity. To be diagnosed with anorexia nervosa a person must meet all of the current DSM 5 criteria. We cannot pinpoint a single cause for anorexia nervosa. It is caused by the complex interaction of various genetic and psychosocial factors, other risk factors include: stress, social isolation, poor emotion regulation strategies, and general psychiatric co-morbidities. In anorexia, Nutritional supplements can improve weight gain, which can reverse the abnormal hematological factors, dermatological factors, bradycardia & abnormal liver enzymes. Although nutritional rehabilitation is an essential component of the physical treatment of anorexia nervosa, psychological treatment is also necessary to address the anxiety issues of the patient.