Simple wasting includes both somatic wasting and exogenous wasting. Systemic wasting is mainly non-progressive wasting with some heritability. Exogenous wasting is usually influenced by various factors such as diet, lifestyle habits and psychology. Inadequate food intake, partial eating, anorexia, missed meals, irregular life and lack of exercise and other dietary and living habits as well as psychological factors such as high work stress, mental tension and overwork are all causes of exogenous wasting. Simple upper body wasting type is a manifestation type of progressive lipodystrophy. Progressive lipodystrophy is a rare autonomic disorder characterized by impaired metabolism of adipose tissue, characterized clinically and histologically by slowly progressive bilateral distribution of basically symmetrical, well-defined, subcutaneous adipose tissue atrophy or disappearance, sometimes combined with limited adipose tissue hyperplasia and hypertrophy. 1. The cause of the disease is unknown. Sissons found that some patients have a combination of glomerulonephritis and hypocomplementemia (C3). A small number of patients have a family history. The pathogenesis is mainly related to hypothalamic lesions and postganglionic sympathetic neuropathy parallel to the spinal nerves. The hypothalamus regulates gonadotropins, thyroid stimulating hormones and other endocrine glands, and has a close anatomical connection with postganglionic sympathetic nerve fibers. There seems to be a boundary between the zone of progressive lipodystrophy where adipose tissue disappears and the normal zone or the obese zone, which seems to have some relationship with the spinal cord segments, usually with waist 1 to 2 as the boundary, dividing the body into two parts: upper and lower body. It is also believed that the hypothalamus and the pituitary gland form a metabolic regulatory control system and that the disappearance of fat is related to the promotion of fat transfer factors produced by this system. There may be a history of acute fever and endocrine defects such as hyperthyroidism, hypopituitarism and mesencephalitis before the onset of the disease. Injury, psychological factors, early menstruation and pregnancy can be causative factors, and there is no unified view on the role of genetic factors.