A large cohort of children was divided into two groups based on their parents' weight status. The high risk group had one or two overweight parent(s) (n = 92, 4.4 +/- 0.5 years), while the low risk group had no parent overweight (n = 95, 4.5 +/- 0.5 years). Weight of the two groups was similar at the start of the study but the high risk group gained marginally more weight over a one year period (P = 0.05). Although total energy intake was similar, the high risk group was consuming a larger percentage of energy from fat (P = 0.0004) and a smaller percentage from carbohydrate (P = 0.0002). Observed physical activity as similar for most levels but marginally higher for the stationary level and marginally lower in total activity in the high risk group. These results suggest a pattern that may lead to increased weight gain in a high risk group as they grow older.