Anorexia Nervosa: An eating disorder that is characterized by the lack or loss of APPETITE, known as ANOREXIA. Other features include excess fear of becoming OVERWEIGHT; BODY IMAGE disturbance; significant WEIGHT LOSS; refusal to maintain minimal normal weight; and AMENORRHEA. This disorder occurs most frequently in adolescent females. (APA, Thesaurus of Psychological Index Terms, 1994)Anorexia: The lack or loss of APPETITE accompanied by an aversion to food and the inability to eat. It is the defining characteristic of the disorder ANOREXIA NERVOSA.Bulimia Nervosa: An eating disorder that is characterized by a cycle of binge eating (BULIMIA or bingeing) followed by inappropriate acts (purging) to avert weight gain. Purging methods often include self-induced VOMITING, use of LAXATIVES or DIURETICS, excessive exercise, and FASTING.Bulimia: Eating an excess amount of food in a short period of time, as seen in the disorder of BULIMIA NERVOSA. It is caused by an abnormal craving for food, or insatiable hunger also known as "ox hunger".Eating Disorders: A group of disorders characterized by physiological and psychological disturbances in appetite or food intake.Refeeding Syndrome: A condition of metabolic imbalance that is caused by complications of initially feeding a severely malnourished patient too aggressively. Usually occurring within the first 5 days of refeeding, this syndrome is characterized by WATER-ELECTROLYTE IMBALANCE; GLUCOSE INTOLERANCE; CARDIAC ARRHYTHMIAS; and DIARRHEA.Amenorrhea: Absence of menstruation.Family Therapy: A form of group psychotherapy. It involves treatment of more than one member of the family simultaneously in the same session.Gastric Dilatation: Abnormal distention of the STOMACH due to accumulation of gastric contents that may reach 10 to 15 liters. Gastric dilatation may be the result of GASTRIC OUTLET OBSTRUCTION; ILEUS; GASTROPARESIS; or denervation.Emaciation: Clinical manifestation of excessive LEANNESS usually caused by disease or a lack of nutrition (MALNUTRITION).Body Image: Individuals' concept of their own bodies.Body Weight: The mass or quantity of heaviness of an individual. It is expressed by units of pounds or kilograms.Body Mass Index: An indicator of body density as determined by the relationship of BODY WEIGHT to BODY HEIGHT. BMI=weight (kg)/height squared (m2). BMI correlates with body fat (ADIPOSE TISSUE). Their relationship varies with age and gender. For adults, BMI falls into these categories: below 18.5 (underweight); 18.5-24.9 (normal); 25.0-29.9 (overweight); 30.0 and above (obese). (National Center for Health Statistics, Centers for Disease Control and Prevention)Feeding Behavior: Behavioral responses or sequences associated with eating including modes of feeding, rhythmic patterns of eating, and time intervals.Weight Gain: Increase in BODY WEIGHT over existing weight.Chilblains: Recurrent localized itching, swelling and painful erythema on the fingers, toes or ears, produced by exposure to cold.Nutrition Disorders: Disorders caused by nutritional imbalance, either overnutrition or undernutrition.Erysipelas: An acute infection of the skin caused by species of STREPTOCOCCUS. This disease most frequently affects infants, young children, and the elderly. Characteristics include pink-to-red lesions that spread rapidly and are warm to the touch. The commonest site of involvement is the face.Eating: The consumption of edible substances.Hypothalamic Diseases: Neoplastic, inflammatory, infectious, and other diseases of the hypothalamus. Clinical manifestations include appetite disorders; AUTONOMIC NERVOUS SYSTEM DISEASES; SLEEP DISORDERS; behavioral symptoms related to dysfunction of the LIMBIC SYSTEM; and neuroendocrine disorders.Dysgeusia: A condition characterized by alterations of the sense of taste which may range from mild to severe, including gross distortions of taste quality.Literature, ModernBone Density: The amount of mineral per square centimeter of BONE. This is the definition used in clinical practice. Actual bone density would be expressed in grams per milliliter. It is most frequently measured by X-RAY ABSORPTIOMETRY or TOMOGRAPHY, X RAY COMPUTED. Bone density is an important predictor for OSTEOPOROSIS.Binge-Eating Disorder: A disorder associated with three or more of the following: eating until feeling uncomfortably full; eating large amounts of food when not physically hungry; eating much more rapidly than normal; eating alone due to embarrassment; feeling of disgust, DEPRESSION, or guilt after overeating. Criteria includes occurrence on average, at least 2 days a week for 6 months. The binge eating is not associated with the regular use of inappropriate compensatory behavior (i.e. purging, excessive exercise, etc.) and does not co-occur exclusively with BULIMIA NERVOSA or ANOREXIA NERVOSA. (From DSM-IV, 1994)Drive: A state of internal activity of an organism that is a necessary condition before a given stimulus will elicit a class of responses; e.g., a certain level of hunger (drive) must be present before food will elicit an eating response.Body Composition: The relative amounts of various components in the body, such as percentage of body fat.