While the adult obesity rate appears to be slowing in the United States, childhood obesity remains historically high, affecting nearly 1 in 5 school-aged children. Many efforts to address this persistent health crisis have urged children to make multiple dietary changes at once—such as increasing physical activity, improving diet, and getting more sleep—but these interventions are often difficult to implement and unrealistic for children and families to sustain.
Interventions that encourage children to make just one dietary change can be a more feasible way to reduce childhood obesity, according to a new study led by Boston University School of Public Health (BUSPH) researchers.
Published in JAMA Network Open , the randomized trial found that children participating in a community-based intervention designed to reduce sugar-sweetened beverage (SSB) consumption had a significantly greater reduction in BMI z-score (zBMI)—a measure used to track BMI in growing children while accounting for age and sex—over 12 months, compared to peers in the comparison group.
The intervention, delivered at Boys & Girls Club (BGC) sites across Massachusetts, included interactive educational sessions, youth-created narratives, and take-home activities focused on reducing sugary drinks and promoting water. SSBs, such as regular sodas, fruit-flavored drinks, sports drinks, and energy drinks, are the largest source of added sugars in children’s diets. These liquid calories do not make children feel full; instead, they contribute to an excess of total daily calories, which can lead to weight gain and raise their risk of developing type 2 diabetes, cardiovascular disease, and dental decay.
As SSB consumption remains stubbornly high among children and adolescents—formative life stages during which people develop eating habits and preferences—the study highlights the value of offering behavioral interventions in trusted community settings to complement clinical approaches aimed at preventing and reducing childhood obesity.
“One of the most striking findings from this study is that we were able to shift our study participants’ BMI in a healthier direction at a time when childhood obesity trends nationally were moving the opposite way,” says study corresponding author Dr. Monica Wang , associate professor of community health sciences at BUSPH, and who co-led the study with Selenne Alatorre, a senior research project manager at BUSPH at the time of the study. “That tells us that well-designed, community-based behavioral interventions can make a meaningful difference, even against a difficult broader backdrop.”
The results also reaffirm that improving children’s health happens far beyond the pediatrician’s office, Dr. Wang says. BGGs serve more than four million school-aged youth, providing academic, social, and leadership skills and structured mentorship through after-school and summer programming across 5,500 sites nationwide. “Community organizations are critical partners in prevention because they are where children spend time, build relationships, and learn from one another,” she says.
For the intervention, dubbed H2GO!, trained BGC staff led 12 in-person group sessions with 437 BGC children ages 8-13, along with a parent or caregiver, to encourage children to reduce their SSB intake and drink more water. Over two-thirds of children in the study qualified for free or reduced priced lunch, and more than half of the children identified as Hispanic or Black. These communities are more likely to face structural barriers to maintaining healthy weight, including economic constraints, neighborhood and environmental conditions that limit access to healthy foods and safe opportunities for physical activity, and unequal access to preventive and other healthcare resources.
Recognizing that these broader conditions shape health, H₂GO! was designed to work within a trusted youth-based setting where children develop everyday habits. Held over multiple waves between 2020 and 2025, the six-week intervention included a mix of interactive and educational lessons such as taste tests and sugar measurement demonstrations; print, music, and video projects created by the children about why drinking water was important to them; and additional take-home activities to complete with their parents.
This work follows an H2GO! pilot study the research team conducted over six months at two BGC sites from 2016-2017, which also resulted in lower zBMI scores and SSB intake among children participating in the intervention. The latest study, a multi-site randomized control trial, expanded this work to BGCs across the Commonwealth, showing that this community-tailored approach is both effective and scalable.
“Our formative work with families and community partners taught us that asking families to change many dietary behaviors at once can quickly become overwhelming, particularly for families facing competing time and financial pressures,” says Dr. Wang. “It is also difficult for a child—or an adult—to simply ‘choose differently’ when sugary drinks are everywhere. We focused instead on one simple, concrete change that did not require a costly or complicated overhaul of family life: drink fewer sugary beverages and more water.”
At the beginning of the study, children consumed an average of 12 ounces of SSBs and 24 ounces of water per day. By the 12-month follow up, children who received the H₂GO! Intervention reported reduced daily SSB intake by an average of 3.6 ounces and increased daily water consumption by an average of 6.6 ounces. In exploratory analyses, the researchers found that nearly 30 percent of the participating children shifted to a lower BMI category over the 12 months, compared to 18 percent of children in comparison sites. Among children who began the study with overweight, 44.4 percent of those in H₂GO! moved into the healthy-weight category, compared with 31.6 percent at comparison sites, while fewer progressed to obesity (5.6 percent versus 21.1 percent). Among children who began with obesity, 47.5 percent of those in H₂GO! moved to a lower BMI category, compared with 36.7 percent at comparison sites.
The H2GO! intervention culminated in a community event in which the children showcased their work and what they learned. Due to measurement differences and limitations, including a reliance on self-reported SSB and water intake, the researchers note that more research is needed to understand whether additional factors may have contributed to the change in children's BMI trajectories. Future work should also consider how this type of intervention could be delivered in other community settings, and applied to other dietary behaviors, such as consumption of ultra-processed foods.
“What I find most encouraging about H2GO! is that it shows we do not have to wait for large-scale policy or environmental change to make progress,” Dr. Wang says. “Those changes are essential, but we can simultaneously give children and families tools to make healthier choices within the environments they live in now. To me, that is an important balance in public health: acknowledging the structural barriers that shape health while also strengthening the agency that families and communities already have.”
The study was funded by the National Institute of Diabetes and Digestive and Kidney Diseases and coauthored by researchers at BUSPH, Harvard T.H. Chan School of Public Health, Boston Medical Center, the University of Connecticut School of Social Work, the Massachusetts Alliance of Boys & Girls Clubs, and the University of Massachusetts T.H. Chan School of Medicine.
JAMA Network Open
10.1001/jamanetworkopen.2026.38188
Randomized controlled/clinical trial
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