What is pureed food when infants are 4-6 months old? In terms of physical properties, pureed foods are foods that contain a liquid content between liquid foods and solid foods. It is drier than liquid food and thinner than solid food, similar to a thick porridge. Both animal-derived and plant-derived foods can be made into purees. From the perspective of physiological maturity: infants in the first year of life during the rapid growth period require a dramatic increase in nutrient density, a rapid increase in nutrient intensity, and a broadening of the nutrient spectrum at any time. Liquid food alone (breast milk or powdered formula) can no longer meet such needs; solid food can meet the nutritional needs of this stage, but infants’ teeth have not yet erupted, chewing ability is insufficient, stomach capacity is insufficient, the development of digestive glands is still at the primary level, the physiological maturity of the digestive tract is not enough to bear solid food. The physiological maturity of the digestive tract is not sufficient to take on solid food. The physiological functions of the mouth, such as the “eating” action and the “holding” and “delivery” of the hands, are not yet mature enough to cooperate with the eating of solid food. Infants must be fed as the main way to eat, and this “feeding” is different from breast and bottle feeding. Liquid food feeding is done by soft tissues and soft substances in contact with the mouth and lips, and by sucking and swallowing. Solid food feeding” requires hand delivery, chewing, oral mixing and swallowing. The feeding of pureed foods is in between, and does not require hand delivery and dental chewing, but only dental cavity pressure, light oral mixing and swallowing; it prepares for solid foods in terms of ability development.