Energy requirements of infants

Objective: To estimate the energy requirements of infants from total energy expenditure and energy deposition during growth. Design: Energy requirements during infancy were estimated from total energy expenditure measured by the doubly labelled water method and energy deposition based on measured protein and fat gains. Setting: Database on the total energy expenditure and energy deposition of infants was compiled from available studies conducted in China, Chile, Gambia, Mexico, Netherlands, UK, and USA. Subjects: Healthy, term infants. Results: Total energy requirements (kJ day(-1)) increased with age and were higher in boys than girls due to differences in weight. Energy requirements decreased from 473 kJ kg(-1) per day for boys and 447 kJ kg(-1) per day for girls at 1 month of age to 337 kJ kg(-1) per day for boys and 341 kJ kg(-1) per day for girls at 6 months of age, and thereafter tended to plateau. Energy deposition as a percentage of total energy requirements decreased from 40% at 1 month to 3% at 12 months of age. These estimates are 10-32% lower than the 1985 FAO/WHO/UNU recommendations which were based on observed energy intakes of infants. Conclusions: Recommendations for the energy intake of infants should be revised based on new estimates of total energy expenditure and energy deposition.