Purpose of review: Improving our understanding of factors driving fat gain in young children should increase our ability to manage the rising problem of obesity. Accordingly, studies associating timing of adiposity rebound with later obesity are reviewed.
Recent findings: Investigations in many countries have confirmed that early adiposity rebound increases risk of high blood pressure and obesity in young adults. The magnitude of the effect can be substantial (>3 body mass index units at 18-21 years) for those undergoing early (<5 years of age) compared with late (>7 years of age) rebound. Early rebound is also associated with impaired glucose tolerance and diabetes in adulthood. Because adiposity rebound is determined using serial measurements of body mass index, the actual changes in body composition occurring during this time are obscured. Recent data show that changing body mass index during adiposity rebound is due to higher than average deposition of weight rather than slowing of the rate of height gain. Moreover, this increased weight gain occurs because of rapid deposition of fat rather than lean tissue, with early rebounders gaining fat mass at almost three times the rate of late rebounders.
Summary: Future work is needed to identify reasons for early adiposity rebound. Because high physical activity and low inactivity are associated with lower body fat during the period of adiposity rebound, studies should be undertaken to see whether stepping up activity can slow fat gain, delay the onset of adiposity rebound and lower adult obesity.