Objective

To investigate the effects of a long-term, individualized and family-based lifestyle intervention on physical activity, sedentary behavior and diet quality in children.

Methods

We carried out a 2-year intervention study in a population sample of 506 children aged 6–8 years in Finland in 2007–2012. We allocated the participants at baseline in the intervention and control group. We assessed physical activity and sedentary behavior by questionnaires and diet by food records.

Results

Total physical activity (+ 9 min/d in intervention group vs. − 5 min/d in control group, p = 0.001 for time*group interaction), unsupervised physical activity (+ 7 min/d vs. − 9 min/d, p < 0.001) and organized sports (+ 8 min/d vs. + 3 min/d, p = 0.001) increased in the intervention group but not in the control group. Using computer and playing video games increased less in the intervention group than in the control group (+ 9 min/d vs. + 19 min/d, p = 0.003). Consumption of vegetables (+ 12 g/d vs. − 12 g/d, p = 0.001), high-fat vegetable-oil based margarine (+ 10 g/d vs. + 3 g/d, p < 0.001) and low-fat milk (+ 69 g/d vs. + 11 g/d, p = 0.042) and intake of dietary fiber (+ 1.3 g/d vs. + 0.2 g/d, p = 0.023), vitamin C (+ 4.5 mg/d vs. − 7.2 mg/d, p = 0.042) and vitamin E (+ 1.4 mg/d vs. + 0.5 mg/d, p = 0.002) increased in the intervention group but not in the control group. Consumption of butter-based spreads increased in the control group but not in the intervention group (+ 2 g/d vs. − 1 g/d, p = 0.002).

Conclusions

Individualized and family-based lifestyle intervention increased physical activity, attenuated increase in sedentary behavior and enhanced diet quality in children.