This study will evaluate the effectiveness of the Bright Bodies intervention in improving body mass index (BMI) among 7-13 year-old children with obesity simultaneously with the impact of the implementation strategy on adoption, reach, fidelity, cost, and maintenance of the intervention in three heterogenous settings serving patients disproportionately affected by obesity.

The demonstrated efficacy of Bright Bodies in a well-designed randomized controlled trial (RCT) and a real-world effectiveness study reduce equipoise and challenge the ethics of a prospective RCT of implementing Bright Bodies in other settings. As such, this study is an observational, multiphase mixed methods design to evaluate effectiveness and implementation among three purposively selected heterogeneous sites serving low-income populations with racial and ethnic, rural-urban, and geographic diversity.

Children ages 7-13 years with BMI ≥85th percentile and their parent/caregivers hereafter referred to as parent will be recruited to participate in the evaluation study from among participants in the newly-established Bright Bodies programs at each of the three implementation sites. The aim is for each site to recruit approximately 40 children and their parents (a total of 120 children and 120 parents) to participate in the Bright Bodies program over the study's enrollment period. The primary outcome is change in BMI expressed as a percentage of the 95th percentile (%BMIp95) using EHR data collected as part of routine clinical care up to 36 months before and up to 15 months after enrollment in the intervention. Secondary outcomes include: (a) change in %BMIp95 at three and six months, (b) changes in parent BMI at three and six months, (d) parent-reported changes in health behaviors (sleep, physical activity, screen time, eating behaviors), via surveys at 3, 6 and 12 months, and (e) changes in parent-proxy reported weight-related quality of life, parent stress, and parent talk about weight via surveys at baseline, 6, and 12 months after enrollment. We will also describe implementation outcomes (reach, adoption, fidelity/adaptation, and cost) through qualitative and quantitative data collection from members of our study team throughout the process of implementation.

Inclusion Criteria:

• Children ages 7-13 years with BMI ≥85th percentile and their parents;
• Child-parent dyads enrolled in the Bright Bodies intervention at each site will be eligible for inclusion in the evaluation study.

Exclusion Criteria:

• Children and/or parents who do not speak the language in which the program will be delivered at each site;
• Children and/or parents who plan to move away from the area within the next 15 months;
• Children with a history of purging and/or dramatic weight loss prior to the trial;
• Children who are currently participating in another high-intensity lifestyle intervention or other similar research study, or are planning to have bariatric surgery within the next six months
• Children whose EHR data cannot be accessed by the study teams;
• Children with chronic medical conditions limiting their ability to take food by mouth (e.g., g-tube fed, total parenteral nutrition), participate in physical activity (e.g., wheelchair bound), or meaningfully participate in group sessions (e.g., cognitive impairment);
• Children with a sibling enrolled in the trial
• Children who join the Bright Bodies program after the 4th week of a session (not including orientation)