The principle of feeding babies is generally on demand, and there is no need to rigidly specify the number of feedings at intervals. Breastfed babies are also fed according to their needs, and are fed when they want to eat. Theoretically, formula-fed babies should also be fed on demand, and formula should be given to babies when they are hungry or have foraging movements. However, because the consistency of formula is generally thicker than breast milk, it takes longer to digest and absorb after feeding, requiring an interval of about 2-3 hours. Therefore, in the actual feeding process, most of the babies are fed formula once every 2-3 hours interval.