Nutritional needs of six-month-old babies Six-month-old babies are in a critical period of physical development, and their nutritional and energy needs will gradually increase. The following are the nutritional needs of a six-month-old baby: 1. Protein A six-month-old baby needs sufficient protein to support growth and development. Breast milk is the best food, rich in protein and nutrients. If your baby is fed milk powder, you should choose milk powder suitable for six-month-old babies, such as infant formula with added supplementary nutrients. However, it is not recommended to add extra protein to your baby to avoid health effects. 2. Calcium and vitamin D. Six-month-old babies need enough calcium.