Energy cost of growth of premature infants.

The objective of this paper is to review approaches to the determination of the energy cost of growth in premature infants. Two approaches are compared: one based on the composition of weight gain, and one based on the determination of energy balance. Data are lacking on the composition of weight gained by the premature infant after birth, while the composition of fetal weight gain and its energy cost can be calculated from data on fetal body composition. These calculations show that energy storage amounts to less than 8.4 kJ/g weight gain below a body weight of 2 kg; the total energy cost of growth is less than 10.5 kJ/g. Estimates twice as high have been obtained from energy balance studies of growing premature infants and older infants. We conclude that the energy cost of growth in premature infants is still uncertain and requires further study.