OBJECTIVE:

To test the hypothesis that family dietary coaching would improve nutritional intakes and weight control in free-living (noninstitutionalized) children and parents.

DESIGN:

Randomized controlled trial.

SETTING:

Fifty-four elementary schools in Paris, France.

PARTICIPANTS:

One thousand thirteen children (mean age, 7.7 years) and 1013 parents (mean age, 40.5 years).

INTERVENTION:

Families were randomly assigned to group A (advised to reduce fat and to increase complex carbohydrate intake), group B (advised to reduce both fat and sugar and to increase complex carbohydrate intake), or a control group (given no advice). Groups A and B received monthly phone counseling and Internet-based monitoring for 8 months.

OUTCOME MEASURES:

Changes in nutritional intake, body mass index (calculated as weight in kilograms divided by height in meters squared), fat mass, physical activity, blood indicators, and quality of life.

RESULTS:

Compared with controls, participants in the intervention groups achieved their nutritional targets for fat intake and to a smaller extent for sugar and complex carbohydrate intake, leading to a decrease in energy intake (children, P < .001; parents, P = .02). Mean changes in body mass index were similar among children (group A, + 0.05, 95% confidence interval [CI], - 0.06 to 0.16; group B, + 0.10, 95% CI, - 0.03 to 0.23; control group, + 0.13, 95% CI, 0.04-0.22; P = .45), but differed in parents (group A, + 0.13, 95% CI, - 0.01 to 0.27; group B, - 0.02, 95% CI, - 0.14 to 0.11; control group, + 0.24, 95% CI, 0.13-0.34; P = .001), with a significant difference between group B and the control group (P = .01).

CONCLUSIONS:

Family dietary coaching improves nutritional intake in free-living children and parents, with beneficial effects on weight control in parents. Trial Registration clinicaltrials.gov Identifier: NCT00456911.