The association of rapid weight gain in early life with increased adiposity and obesity in later life has been established, whereas whether rapid neonatal weight gain predisposes individuals to other risk factors for cardiovascular disease and type 2 diabetes mellitus remains controversial. Gain in weight of >0.5 SD scores in the first 3 months of life (described as rapid weight gain) is associated with an unfavourable health profile in adulthood, and keeping weight gain below this threshold could reduce the risk of cardiovascular and metabolic diseases later in life. Weight gain above this threshold is not necessarily unhealthy if the increase is in proportion with the increase in length. As such, regular measurement of both the weight and length of all infants is important. Preterm infants and those who are born small for gestational age are most likely to have rapid weight gain, and are high-risk populations for unfavourable health profiles in adulthood.