H2GO! program in 11 Boys & Girls Clubs: zBMI difference of −0.19 at 12 months in a randomized trial

A cluster randomized clinical trial published in JAMA Network Open evaluated H2GO!, a community-based behavioral intervention, at 11 Boys & Girls Club sites in Massachusetts. The trial ran from September 2020 to June 2025 and enrolled 437 children aged 8 to 13 together with their parents or caregivers. At 12 months, the adjusted between-group difference in BMI z score (zBMI) change was −0.19 (95% CI, −0.38 to −0.01; P = .04) jamanetwork.comJAMA Network Openjamanetwork.comOpen source ↗.

Sites were pair-matched and randomized either to the intervention or to usual programming. The mean age of the children was 10.1 years, and 68% were eligible for free or reduced-price lunch. At baseline, 16.9% of the children had overweight and 36.8% had obesity.

Intervention and design

The program consisted of twelve in-person group sessions over 6 weeks, delivered by trained club staff. The aim was to reduce sugar-sweetened beverage intake and increase water consumption through health sessions, youth-created narratives and parent-child activities. Comparison sites kept their usual activities.

Outcomes were assessed at baseline and at 2, 6 and 12 months, with intention-to-treat analysis. The primary outcome was the 12-month change in zBMI, calculated from height and weight measured by staff using standardized protocols. Intake of sugar-sweetened beverages and water was measured with a validated questionnaire jamanetwork.comJAMA Network Openjamanetwork.comOpen source ↗.

Results and limitations

Within groups, the mean zBMI change was −0.11 (95% CI, −0.25 to 0.02) in the intervention group and 0.08 (95% CI, −0.04 to 0.20) in the comparison group; neither change was statistically significant on its own. According to the publication's retelling, the difference between groups was not present at 2 or 6 months.

Between-group differences in sugar-sweetened beverage and water intake were not significant. The authors wrote that this calls for caution when interpreting what drove the change in BMI. Intake was self-reported and therefore less precise than the measured height and weight. In an analysis the authors label exploratory, 44.4% of children who started with overweight reached the healthy-weight range in the program group, versus 31.6% at comparison sites.

The authors also listed limitations: children attended about half of the sessions on average, about 69% remained in the study at 12 months, families knew which condition their club was in, and all sites were in one state. One comparison site stopped enrolling partway through and was replaced, so unmeasured differences between sites may have affected the results. The trial is registered at ClinicalTrials.gov (NCT04265794) jamanetwork.comJAMA Network Openjamanetwork.comOpen source ↗.