Could swapping sugary drinks for water help children maintain a healthier weight? A new study suggests that one simple change in drinking habits, supported by an engaging after-school programme, could make a meaningful difference. Researchers at Boston University School of Public Health (BUSPH) found that children who participated in a community-based intervention aimed at reducing sugary drink consumption showed improvements in their body mass index (BMI) over 12 months.

Published in JAMA Network Open, the randomised trial offers a promising approach to addressing childhood obesity, which affects nearly one in five school-aged children in the United States. Rather than asking families to overhaul their diets, increase exercise and improve sleep simultaneously, the intervention focused on a single achievable goal: drinking fewer sugar-sweetened beverages and more water.

The programme, called H₂GO!, involved 437 children aged eight to 13 at Boys & Girls Club locations across Massachusetts. Trained staff delivered 12 interactive sessions over six weeks, combining educational activities, taste tests, sugar measurement demonstrations and creative projects. Children produced music, videos and stories promoting water consumption, while parents and caregivers participated through take-home activities.

The results were encouraging. Compared with children at other club locations, participants showed significantly greater reductions in BMI z-scores, a measure that accounts for children’s age and sex. Nearly 30% of participating children moved into a lower BMI category after 12 months, compared with 18% in the comparison group, according to exploratory analyses.

Among children who began the study overweight, 44.4% of those receiving the intervention reached the healthy-weight category, compared with 31.6% at comparison sites. Children in the programme also reported drinking an average of 3.6 fewer ounces of sugary beverages and 6.6 more ounces of water daily by the 12-month follow-up.

Study co-leader Dr Monica Wang, associate professor of community health sciences at BUSPH, said the findings demonstrate how community-based programmes can improve children’s health even as childhood obesity remains a major national concern. She emphasised that meaningful prevention efforts need not be confined to medical settings, particularly when trusted community organisations already play an important role in children’s daily lives.

The researchers also recognised that healthier choices are not always easy. Families may face financial pressures, limited access to nutritious foods and environments where sugary drinks are readily available. By concentrating on one affordable, practical change, H₂GO! sought to make healthier habits easier to adopt without placing additional burdens on families.

Although the findings are promising, researchers acknowledged limitations, including reliance on self-reported beverage consumption. Further studies are needed to determine whether other factors influenced BMI changes and whether similar programmes could succeed in different communities. Nevertheless, the findings suggest that small, manageable lifestyle changes, reinforced through community support, may offer a practical way to help children develop healthier habits.

More information: Monica Wang et al, A Community-Based Behavioral Intervention and Body Mass Index in School-Aged Children – A Cluster Randomized Clinical Trial, JAMA Network Open. DOI: 10.1001/jamanetworkopen.2026.38188

Journal information: JAMA Network Open Provided by Boston University