Healthy infant growth: what are the trade-offs in the developed world?

More rapid infant weight gain is associated with long-term benefits, such as better neurodevelopmental outcomes for some infants, but also with harms, such as an increased risk of later obesity and higher blood pressure. Determining the optimal rate of infant weight gain requires balancing these benefits and risks, the magnitude of which appears to differ for specific populations of infants. Among healthy full-term infants, gain in weight-for-length is associated with obesity and adverse cardiometabolic outcomes, with no substantial benefit to neurodevelopment. Preterm infants derive substantial neurodevelopmental benefit from gain in weight-for-length during the neonatal intensive care unit stay, and possibly from linear growth thereafter; excess weight-for-length gain may predict adverse cardiometabolic outcomes. Among full-term SGA infants, evidence is limited; excess weight-for-length gain in infancy may predict later cardiometabolic risk, but does not appear to modify neurodevelopmental outcomes. Future research should consider not just the magnitude but also the value of the various outcomes in each population. More work is also needed to identify shared determinants of rapid early weight gain, cardiometabolic risk, and neurodevelopment, and to differentiate effects of weight gain that is proportional to linear growth from weight gain that is excessive.