Background: Rapid weight gain in early life may increase the risk of overweight and obesity in adulthood. We investigated the association between the rate of growth during early childhood and the development of overweight and obesity in young adults.

Methods: We used a prospective cohort study of 2077 young adults who were born between 1981 and 1984 in Brisbane, Australia and had anthropometry measurements available at birth, 6 months, 5 years, 14 years and 21 years of age. The associations of rate of early growth with body mass index (BMI), waist circumference (WC) and waist-to-hip ratio (WHR) and their categories at 21 years were studied using multivariate analysis.

Results: We found that rapid weight gain [> + 0.67 standard deviation score (SDS)] in the first 5 years of life was associated with young adults’ overweight status (BMI: adjusted OR = 2.35, 95 % CI, 1.82–3.03; WC: adjusted OR = 2.20, 95 % CI, 1.65–2.95). We also observed that slow weight gain in the first 5 years of age (< −0.67 SDS) was inversely associated with overweight (BMI: OR = 0.62, 95 % CI, 0.45–0.84). Such associations were not found with WHR. Rapid weight gain in the first 6 months of life increased the risk of overweight as defined by BMI (adjusted OR = 1.13, 95 % CI, 0.86–1.49) and WC (adjusted OR = 1.24, 95 % CI, 0.92–1.67), but these associations were not statistically significant.

Conclusion: Rapid weight gain in the first 5 years of life in children increased their risk of a higher BMI and WC in young adulthood, in contrast slow weight gain was inversely associated with weight status at 21 years.