Constant growth of primary school children throughout four seasons of year.

Repeated measurements of body size (11 times for weight and 4 times for height during a 13 month period) in 1982-1983, and then in 1983-1984 disclosed that primary school children, both boys and girls in every year grade from 1st to 6th, grow in weight and height almost linearly throughout a year. Seasonal variation in growth pattern, once evident in around 1960, was no longer observed. Based on the observation, a formula to predict gains in weight and height is proposed and its value for the prevention of childhood obesity is discussed.