Energy intakes of human milk-fed infants during the first year.

A discrepancy between current recommendations for energy intakes and the reported intakes of human milk-fed infants has led to the suggestion that energy requirements of infants should be reevaluated. Gross energy intakes of 1-month-old, exclusively breast-fed infants are similar to recommended amounts of metabolizable energy; however, by 4 months of age, gross energy intakes of exclusively breast-fed infants are significantly less than current recommendations. Weight-for-age percentiles also fall during that period. Energy intakes (measured in kilocalories per kilogram) persist at less than recommended amounts, and weight-for-age percentiles continue to drop after solid foods are added to the diet. Energy intakes of formula-fed infants appear significantly higher than those of infants who are fed human milk. Growth rates, total daily energy expenditure, sleeping metabolic rates, minimal rates of energy expenditure, rectal temperature, and heart rates have been found to be lower in breast-fed infants. The maintenance of energy intakes and growth trajectories during the period of demand supplementation with solid foods suggests that intakes, growth rates, and rates of energy expenditure of human milk-fed infants are physiologic responses to an appropriate dietary intake.