1. What is infant and child malnutrition? How is it caused? Infant and young child malnutrition is the infant and young child energy deficiency, the main reasons are long-term improper diet, calorie deficiency. Most commonly seen in less than 3 years old. Such as artificial feeding mainly starchy food, or insufficient breast milk and do not add complementary food, or weaning infants can not adapt to new things, congenital anomalies such as cleft lip, cleft palate to feeding difficulties; digestive system diseases such as enteritis, acute dysentery, pediatric hepatitis; chronic wasting diseases such as recurrent pneumonia, tuberculosis, etc. 2.What are the manifestations of malnutrition? Malnutrition is divided into three degrees: First degree: weight than the normal average weight decreased by 15% to 25%, femur, trunk subcutaneous fat thinning, abdominal fat folds thickness <0.8cm, length, body temperature and general state is not yet changed. Second degree: weight decreased by 25%~40% compared with normal average weight, length also less than normal, abdominal subcutaneous fat layer almost completely disappeared, skin pale, flaccid and inelastic, ribs and back bone protruded, child could not stand, sleep restlessly, eating difficulties. Third degree: weight is more than 40% less than the normal average weight, length is lower than normal, growth is delayed, hip and facial fat are gone, forehead and facial wrinkles, pale, dry skin, completely inelastic, body temperature is lower than normal, heart rate accelerates or slows down, blood pressure is low, appetite is low or disappears, mental excitement or indifference. 3, infant malnutrition should be how to prevent? (1) promote breastfeeding, such as breast milk is not enough, should be supplemented instead of milk protein food, such as cow and goat milk, soy milk, fish. Those without breast milk should be replaced by reasonable milk substitutes containing good protein, often milk, goat milk. (2) Timely vaccination to prevent the occurrence of infectious diseases in order to reduce nutrition and the consumption of the organism. Actively control the advocacy of chronic diseases. Ensure that children get enough sleep and eat regularly. Strengthen the physical exercise of children to increase their physical fitness. (3) Add supplementary food on time. From less to more, from simple to complex, from thin to thick, step by step. Add a little vegetable water in March, egg yolk and porridge in April, pureed vegetables, juice and eggs in June, steamed eggs, chopped liver and tofu in July and August, and protein foods in September and December. Each addition of the same complementary food should depend on the digestive situation, 3-5 days stool before adding other types or increase the amount. (4) Children with malnutrition in early childhood and childhood should create and comfortable environment to encourage them to eat. (5) Pay attention to the child's appetite and stool digestion each time the diet is adjusted. (6) Regular weight measurement to understand the effect of dietary adjustment. (7) Do personal hygiene, add clothes in time and prevent from getting cold. For small infants with severe malnutrition, go to public places less often to prevent cross-infection.