(RxWiki News) Do laws regarding vending machines and fast food carts in schools make a difference in whether teens gain weight? That's what a group of researchers sought to find out.
They determined that such laws related to "competitive food" can make a difference in whether teens continue to gain weight - but only if the laws are consistent and comprehensive enough.
"Talk to your pediatrician if you your child's weight is an issue."
The study, led by Daniel R. Taber, PhD, MPH, of the Health Policy Center in the Institute for Health Research and Policy at the University of Illinois at Chicago, relied on a legal database called Westlaw to identify laws related to "competitive food."
"Competitive food" is the official term for food and drinks sold outside of federal meal programs, such as snacks sold in vending machines or meals sold by fast food businesses inside schools, such as a pizza stand.
Dr. Taber and his colleagues ranked the laws they found for each state and classified the states as having strong laws, weak laws or no laws at all related to competitive food. They focused on the laws that existed in the years 2003 and 2006.
Then the researchers gathered information on the height and weight of 6,300 students when they were fifth grade (2004) and then again when they were in eighth grade (2007) across 40 states.
The students were all part of a larger study called the Early Childhood Longitudinal Study — Kindergarten Class. The researchers looked at which children were overweight or obese and whether the students' overall weight changed from 2004 to 2007.
They found that students living in states with strong laws related to competitive food gained an average of .25 fewer units of body mass index. Body mass index (BMI) is the ratio of a person's weight to their height and is used to determine whether they are a healthy weight or overweight.
Children living in states with the strong competitive food laws were also less likely to remain overweight or obese over those three years than students who lived in states with no competitive food laws.
Students living in states with weak competitive food laws had a similar gain in their BMI as children living in states with no competitive food laws.
The researchers therefore concluded that it is not only the presence of laws that affects children's weight gain but also how effective they are.
"Laws that regulate competitive food nutrition content may reduce adolescent BMI change if they are comprehensive, contain strong language, and are enacted across grade levels," they wrote.
The researchers noted in their background information that many interventions that have tried to reduce teen obesity through education - promoting a healthy diet and exercise - have not been very successful.
They said experts have argued that education will not be effective if steps are not taken to change the environment teens live in, which is full of "countless sources of high-caloric-density, low-nutrient-density foods and beverages."
Their study, they wrote, "strengthened the evidence that competitive food laws may improve adolescent weight status." But laws must be written and targeted well.
"The results of this study clearly indicate that strength of language, comprehensiveness, and consistency of new competitive food standards" are essential to help reduce teen obesity.
The study was published August 13 in Pediatrics. The research was funded by the Robert Wood Johnson Foundation, the National Heart, Lung and Blood Institute and the National Cancer Institute. The researchers declared no conflicts of interest.