Drinking a glass or two of water before a meal has been proven to help obese adults lose weight, but what about when elementary school students do it? A team from several New York research Institutions developed a simple weight loss program in New York City public schools. Using self-serve water dispensers, called “water jets,” increased water consumption among students and impacted weight loss.

"Decreasing the amount of caloric beverages consumed and simultaneously increasing water consumption is important to promote children's health and decrease the prevalence of childhood obesity," said the study’s co-author Amy Ellen Schwartz, director of the New York University Institute for Education and Social Policy, in a press release . "Schools are a natural setting for such interventions."

In 2009, New York City’s Department of Health introduced the water jets — large, clear electronically powered jugs that dispense water with a push of a button. At roughly $1,000 each, 40 percent of the 1,227 elementary and middle schools in the city received one for the study. The other 60 percent of schools served to compare the effects of the water machines. Researchers also measured and recorded the height and weight of each student from the 2008 to 2013 academic school years — this allowed them to compile data on body mass index (BMI) for over a million students.

Students whose BMIs fell between 18.5 and 24.9 were categorized as normal weight, while those with a BMI of 30 and greater were considered obese. In just three months, researchers saw the students’ BMI drop 0.25 for boys and 0.22 for girls. During the same period, milk purchases dropped by roughly 12 half-pint cartons per student each year — the assumption was students were substituting milk with water. With nearly 40 percent of children in New York City being overweight or obese , the research shows these water jets could help to reverse obesity trends, even in schools on tight budgets.

One in six children and adolescents are obese in America, according to the Centers for Disease Control and Prevention . These rates have steadily increased over the last 30 years, prompting researchers to look into effective weight loss programs that can be implemented at a low cost.

"Doing something as simple as providing free and readily available water to students may have positive impacts on their overall health, particularly weight management," said the study’s lead author Brian Elbel, a population health professor at NYU Langone Medical Center, in a press release . "Our findings suggest that this relatively low-cost intervention is, in fact, working."

Source: Elbel B, Schwartz E, and Moynihan DP, et al. JAMA Pediatrics . 2016.