Individual, dyadic, collaborative planning, physical activity, and nutrition: A randomized controlled trial in parent-child dyads.

Objective: This study was designed to investigate the effects of individual, dyadic, and collaborative planning on moderate-to-vigorous physical activity (MVPA; primary outcome) and energy-dense food intake (secondary outcome) in dyads of parents and their 9-15-year-old children. Individual planning reflects an "I-for-me" planning of one person's behavior. Collaborative ("we-for-us") planning refers to joint planning of both dyad members' behavior, whereas dyadic ("we-for-me") planning involves joint planning of only the target person's behavior.

Method: N = 247 dyads participated in a randomized controlled trial with individual, dyadic, or collaborative physical activity (PA) planning and control conditions (education about PA, sedentary behavior, nutrition, energy intake-expenditure balance). MVPA was measured with ActiGraph wGT3X-BT accelerometers at baseline, 1-week, and 36-week follow-ups. Energy-dense food intake was self-reported at baseline, 9-week, and 36-week follow-ups. Linear mixed models were fit for parents and children separately.

Results: At the 36-week follow-up, children in the dyadic "we-for-me" planning condition decreased their MVPA compared to the control condition. At the same time, children in the dyadic planning condition also decreased energy-dense food intake at the 36-week follow-up. No effects were found among children in individual and collaborative PA planning conditions. Parents in any experimental conditions decreased energy-dense food intake.

Conclusions: Children's decrease in MVPA in dyadic PA planning condition was offset by a reduction of energy intake, which may represent a compensatory mechanism. The limited effectiveness of the dyadic "we-for-me" interventions in parent-child dyads may result from young people's needs for individuation and their reactance to parental support. (PsycInfo Database Record (c) 2024 APA, all rights reserved).