Students at elementary and secondary schools that offer healthier food offerings and more opportunities for physical activities have a healthier body mass index, according to Rutgers researchers.

The study, published in Preventive Medicine Reports, uses professional measures of students’ height and weight – the gold standard for studying childhood obesity – in a study on the effects of a school’s food offerings and physical activity environment.

Almost one in five children and adolescents in the United States are obese. Since children eat up to two meals per day and can get 40 percent of their daily physical activity at schools, schools play a major role in obesity-related behaviors. Although recent policies and programs, such as the National School Lunch Program, have focused on promoting healthier school environments, there is little evidence of the consequences for children’s weight.

The study looked at the healthfulness over the period of one school year of items offered in school lunches, vending machines and other school food offerings, as well as the number of indoor and outdoor physical activity facilities and physical activity opportunities at 90 public schools that serve 19,000 students in Newark, Trenton, Camden and New Brunswick.

Researchers found that healthier food offerings and a greater number of physical activity facilities were associated with lower body mass index, on average, for students. Schools that offered an additional unhealthy item in vending machines were associated with higher student weight and those that had an additional outdoor physical activity facility correlated with lower student weight.

“Evidence of the importance of school meals and of enforcing healthy nutritional standards is particularly timely given current federal proposals to roll back those standards,” said Michael Yedidia, who co-directs the New Jersey Child Health Study at the Rutgers Center for State Health Policy. “These meals are critical to the health of low-income students, who are 80 percent of those served by federal school meals programs. They provide up to half of the students’ nutritional needs at low or no cost to parents.”

The findings will be particularly relevant for discussions on Child Nutrition Reauthorization, the key piece of federal legislation that supports school food programs, said Punam Ohri-Vachaspati, a study co-author at Arizona State University. “Schools play a critical role in providing environments to support healthy habits among children that can influence their short and long term-health,” she said.

The research was conducted as part of the New Jersey Child Health Study, a collaboration among researchers at the Rutgers University Center for State Health Policy at Rutgers Institute for Health, Health Care Policy and Aging Research and the College of Health Solutions at Arizona State University. It is supported by grants from the National Heart, Lung and Blood Institute and the National Institute of Child Health and Human Development at the National Institutes of Health.