Calories Or Miles Walked? How Should We Communicate About Energy Content Of Drinks?

by Sheryl Rifas-Shiman, MPH

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The FDA recently released two new regulations that provide instructions to restaurants, grocery stores, vending machines and other food establishments for how they will have to comply with the law compelling them to post calories on menus. The idea motivating this law and regulations is that if consumers are aware of the calories of their purchases, they may make lower calorie choices. Is this true? Does the posting of calories or other nutritional information affect consumer choice? And if so, does the nature of the posted information make a difference? 

In a recent study in the American Journal of Public Health, Sara Bleich and colleagues investigated these questions by posting 1 of 4 signs about sugar-sweetened beverages (SSB) at 6 corner stores in low-income Baltimore neighborhoods. The first sign provided calorie counts for a typical bottle of soda or fruit juice, the second provided the number of teaspoons of sugar in a bottle of soda/fruit juice, and the other two provided the number of minutes of running or miles of walking necessary to burn off a beverage. 

They tracked the effect of the signs by cataloging purchases of Black adolescents shopping at the stores. What happened?  The signs appeared to work. When compared to the time period prior to the signs being up, the signs appeared to lead adolescents to purchase fewer calories from beverages, be less likely to buy a SSB in the first place or buy a SSB over 16 ounces. These effects persisted even after the signs were taken down. Interviews with some of the adolescents, as they were leaving the stores during the intervention, seemed to confirm their response to the signs. 40% recalled seeing the signs and said they changed their purchase as a result.

Perhaps the most interesting result, however, is that the type of calorie information contained in the signage seemed to make little difference. All were better than no signs and didn’t substantially differ from one another. Similarly, the type of signage did not have an impact on the responses from exit interviews.

A notable limitation of this study is that they did not have a control store.  They used a case-crossover design where each store served as their own control.  This design might not entirely control for changes over time.  Nevertheless, the results suggest that while the type of information posted may not be significant, the mere fact that the signs exist may lead to better beverage choices. This may provide good news for the calorie labeling regulations, which will be up by the end of the year. Maybe, providing this nutritional information in lots of ways (as they did in this study), but at the same time, will work better than providing it as just calories.