Efforts to curb childhood obesity through school vending machine restrictions and making soft drinks more expensive with low levels of additional taxation have had a negligible effect, to date, on the waistline of America's youth, a new study led by the Yale School of Public Health has found. The paper appears online in Health Affairs.

Researchers studied whether the two policy approaches have slowed what many regard as a childhood obesity epidemic that has been fueled, in part, by growing consumption of soda and other sugar-based beverages. Lead researcher Jason M. Fletcher, Ph.D., an assistant professor in the Yale School of Public Health, said evidence shows that as currently practiced, neither public health policy is working.

"Our strongest finding is that current policies of low soda taxes and incremental soft drink restrictions do not lead to any noteworthy weight reductions in children," Fletcher said.

"However, it remains possible, and perhaps likely, that more comprehensive policies -- such as higher taxes and a complete ban on sodas at school -- could work."

Fletcher and co-authors David Frisvold of Emory University and Nathan Tefft of Bates College said that children are not deterred by vending machine bans. They simply find high-calorie substitutes or get soft drinks elsewhere. In schools that allow access to soft drinks, 86% of the students reported consumption within the past week, the study found. In schools without access, 84% of the students still consumed the beverages.

The researchers also found that any increase in soda taxes would have to be substantial to make a difference. They believe that increasing the tax to 6% (more than double the current rate) would result only in a small reduction in weight.

The prevalence of obesity in children ages 6-19 has approximately tripled since the late 1970s. Many health professionals believe that soda consumption is one of the factors driving this change. Soda intake has increased 500% in the past 50 years and is now the single largest category of calories for children, even surpassing milk.

The research was funded by the Robert Wood Johnson Foundation through a Healthy Eating Research grant.

From the April 12, 2010, Prepared Foods E-dition