Nutrition in infancy and long-term risk of obesity: evidence from 2 randomized controlled trials

Abstract

Background: Growth acceleration as a consequence of relative overnutrition in infancy has been suggested to increase the risk of later obesity. However, few studies have investigated this association by using an experimental study design.

Objective: We investigated the effect of early growth promotion on later body composition in 2 studies of infants born small for gestational age (weight <10th percentile in study 1 and <20th percentile in study 2).

Design: We reviewed a subset of children (n = 153 of 299 in study 1 and 90 of 246 in study 2) randomly assigned at birth to receive either a control formula or a nutrient-enriched formula (which contained 28-43% more protein and 6-12% more energy than the control formula) at 5-8 y of age. Fat mass was measured by using bioelectric impedance analysis in study 1 and deuterium dilution in study 2.

Results: Fat mass was lower in children assigned to receive the control formula than in children assigned to receive the nutrient-enriched formula in both trials [mean (95% CI) difference for fat mass after adjustment for sex: study 1: -38% (-67%, -10%), P = 0.009; study 2: -18% (-36%, -0.3%), P = 0.04]. In nonrandomized analyses, faster weight gain in infancy was associated with greater fat mass in childhood.

Conclusions: In 2 prospective randomized trials, we showed that a nutrient-enriched diet in infancy increased fat mass later in childhood. These experimental data support a causal link between faster early weight gain and a later risk of obesity, have important implications for the management of infants born small for gestational age, and suggest that the primary prevention of obesity could begin in infancy.