Stanford Healthy Goals Study

We propose a 2-arm, parallel group, randomized controlled trial to test the efficacy of adding two innovative "wise" social psychological interventions-growth mindset and self-affirmation-to a 6-month usual care family-based, group behavioral intervention for weight control in children with obesity, to reduce body mass index trajectory over 12 months, compared to the usual care behavioral intervention alone.

A total of 200 10-15-year-old children with obesity (BMI ≥ 95th percentile) will participate. All children will participate with their parents in a usual care six-month, family-based, group, behavioral weight control program. In addition, families randomized to the wise intervention condition will receive two, innovative social psychological interventions-growth mindset and self-affirmation-strategically selected and timed to enhance the behavioral intervention.

There remains a great need for innovative approaches to increase and sustain weight loss among children with obesity. We propose that existing weight control interventions are limited in their success with many children in part because of the many psychological barriers and threats they face when attempting to manage their weight. One novel and potentially effective and efficient way to enhance the success of behavioral treatments may be to focus on changing the mindsets and preparedness of the participant.

Measures will be collected at baseline, 3 months, 6 months (end of the behavioral treatment), and 12 months (follow-up 6 months after the end of treatment) from children and parents. Body mass index (BMI) trajectory over the entire 12 months is the primary outcome measure. Secondary outcome measures and potential moderating and/or mediating variables include waist circumference and triceps skinfold thickness, parent weight outcomes, physical activity (accelerometery), energy intake (24-hour dietary recalls), screen time, and hypothesized mediators of the behavioral intervention and the two social psychological interventions. We propose highly rigorous and transparent RCT methods.

Primary Hypothesis: Compared to children randomized to receive the usual care family-based, group behavioral weight control program alone, children randomized to receive the usual care family-based, group behavioral weight control program plus the wise social psychological interventions will have a significantly attenuated BMI trajectory over 12 months.

Secondary Analysis: We will examine the effects of the intervention on secondary outcome measures and explore possible moderators and mediators of intervention responsiveness. Sex will be examined as a biological variable, and we will perform risk factor/targeting and process/delivery of intervention analyses.

Innovation: This research is particularly exciting because it: 1. tests a novel theory and paradigm for pediatric weight control, one that emphasizes how precisely changing perceptions of oneself and one's environment can unleash one's ability to benefit from available resources and behavioral strategies, 2. introduces a new theory of change for weight control, involving small changes in perceptions triggering recursive feedback loops that domino into large changes in weight over time, 3. applies methods from educational research, to a new domain of weight control, and 4. involves a truly transdisciplinary effort between social psychology and health creating a fundamentally new, integrated approach to health behavior change.

Inclusion criteria

• 10-15 year old children with obesity (BMI ≥ 95th percentile on the 2000 Centers for Disease Control and Prevention BMI reference) on the date of randomization. - Participation in a behavioral weight control program. Standard behavioral weight control program eligibility criteria will apply: Child and at least one parent/guardian must agree to participate

Exclusion criteria

• Medical conditions affecting growth
• Medications affecting growth
• Conditions limiting participation in the interventions
• Conditions limiting participation in the assessments
• Unable to read, understand or complete informed consent in English or Spanish