Breast milk is a liquid tissue that is the most ideal source of nutrition for infants, and for most infants, breast milk meets all nutritional needs (including water) until six months. Six months is the optimal time for infants to begin to adjust to different foods, different food structures and feeding methods. The gradual addition of solid foods will allow infants to slowly adjust to different foods. The practice of starting complementary foods at four months of age has been gradually phased out by almost all official, authoritative organizations in the world since 2001. The World Health Organization, the American Academy of Pediatrics, the Chinese Ministry of Health and other authoritative bodies recommend adding complementary foods at around six months, mainly for the following reasons: 1. Salivary amylase is excellent at birth, but pancreatic amylase (along with salivary amylase, responsible for digesting starchy substances) is not yet available for at least the first three months, and is insufficient for at least six months. Therefore, during the first six months, the ability to digest starch is very limited, although not completely absent. 2. The more you suck, the more breast milk you get: If the time of breastfeeding decreases, the mother’s milk production will also decrease due to the stimulation, so that the baby can not get enough “optimal nutrition”. In addition, babies have much smaller stomachs than adults, and complementary foods take up less stomach capacity than they already have. Reducing breastfeeding within six months can cause malnutrition in children in some extreme cases. 3, need to wait for the push tongue reflex to disappear: newborns have an innate conditioned reflex – push tongue reflex, also known as the jerk tongue reflex, that is, the tongue will enter the mouth of solid food (or spoon) to push out, in order to prevent foreign objects into the throat to cause asphyxiation, this reflex will generally disappear around 6 months of life. If the supplement is introduced at a stage when the child is not yet developed and should be fed the supplement (when the tongue-pushing supplement is still strong), the infant will resist the spoon (it is too hard). At this point the mother may think that the child is refusing to eat, but what the baby is actually resisting is the hard object placed in his/her mouth. Introducing solids too early does not shorten the child’s tongue-pushing reflex, it simply lengthens the time it takes for the child to accept solids. But by six months, the baby’s eating behavior begins to develop from sucking to biting, and by 7-9 months, it gradually becomes chewing. 4, need to wait until the baby can sit independently: can sit independently means that the child can better handle food in the mouth before swallowing, thus guaranteeing that the baby can eat safely. 5. Need to wait for the immune system to develop: adding complementary foods too early may cause food allergies, and exposure to pathogens in food may increase the chance of diarrhea and other diseases. The American Academy of Pediatrics’ 2012 Breastfeeding Report says that babies who are exclusively breastfed for greater than four months, but who add complementary foods before six months, are four times more likely to develop pneumonia than babies who are exclusively breastfed until after six months. Exclusive breastfeeding until six months, respiratory syncytial virus bronchitis heavy degree reduced by 74%, heavy colds and throat infections reduced by 63%. 6, need to wait for the baby interest formation: most babies in about six months began to produce the willingness to accept new food structure and taste, but also began to like to imitate the behavior of adults. At this time, the gradual introduction of new tastes and food types to develop and explore the child’s ability to behave at this stage is very useful. In 2002, the 55th World Health Assembly adopted the Global Strategy for Infant Feeding, which emphasizes exclusive breastfeeding for 6 months after birth and the reasonable addition of complementary foods after 6 months. in January 2012, the Chinese Ministry of Health issued the “Maternal and Infant Health Literacy – Basic Knowledge and Skills (for Trial Implementation)”, which clearly states that infants should gradually add complementary foods starting from 6 months after birth. At the same time, the Ministry of Health also released the “Report on the Nutritional Development of Children 0-6 Years Old in China (2012)” in May 2012, which also advocates exclusive breastfeeding for infants within 6 months and the gradual addition of complementary foods after 6 months.