Fighting adolescent obesity with a healthy message has sweet effects. Researchers studied how adolescents made purchasing choices after being exposed to four different messages about sugar-sweetened drinks. Some decided against drink purchases altogether, according to the study published online Oct. 16 in the American Journal of Public Health.

First author Sara N. Bleich, PhD, of the health policy and management department at Johns Hopkins Bloomberg School of Public Health in Baltimore, and colleagues used four caloric messages, all describing the same intake on separate signs posted one at a time for two-week periods. The signs were placed in six stores within five blocks of middle and high schools in low-income, predominantly black zip codes.

The messages described the contents of a 20-ounce bottle of sugared beverage, either in total calories (250 cal), teaspoons of sugar (16 tsp), minutes of running (50 minutes), or distance walking (five miles). The physical activity equivalents were calculated based on the energy balance equation, assuming a 15 year-old person weighing 110 pounds.

Over the course of 10 months between August 2012 and June 2013, Bleich et al collected data on purchases and quantity of beverages purchased at baseline, across the four interventional periods and in a postinterventional period. The research teams used the postinterventional period to determine if the signs had lasting impact. They also conducted exit interviews to capture whether teens had seen the signs, understood them, believed them and to find out if purchases had been influenced.

Across the interventional period, they found adolescents reduced their caloric purchases accordingly. Average purchases at baseline were around 149 calories. This dropped to an average of 121 calories across the four interventions. Beverage size was also reduced.

Information presented as miles of walking reduced average calorie purchases more than when presented as teaspoons of sugar or minutes of running (190 kcal vs. 194 kcal vs. 201 kcal, respectively). More water and diet soda sold during the intervention over baseline, and fewer soda and sports drinks were sold over baseline. The frequency of large-volume sugared beverage purchases dropped from 27 percent at baseline to 16 percent during the intervention. Similarly lowered rates were seen even after the signs were removed.

During the random exit interview sampling, one-third of teens noted seeing the signs and of those, 40 percent reported the signs influenced a change in their purchases.

"This is a very low-cost way to get children old enough to make their own purchases to drink fewer sugar-sweetened beverages and they appear to be effective even after they are removed," Bleich said in a press release. “Black adolescents are one of the groups at highest risk for obesity and one of the largest consumers of sugary beverages. And there is a strong scientific link between consumption of sugary beverages and obesity. Using these easy-to-understand and easy-to-install signs may help promote obesity prevention or weight loss."