摘要：Objectives. We examined the effect of an intervention to provide caloric information about sugar-sweetened beverages (SSBs) on the number of SSB purchases. Methods. We used a case-crossover design with 4 corner stores located in low-income, predominately Black neighborhoods in Baltimore, Maryland. The intervention randomly posted 1 of 3 signs with the following caloric information: (1) absolute caloric count, (2) percentage of total recommended daily intake, and (3) physical activity equivalent. We collected data for 1600 beverage sales by Black adolescents, aged 12–18 years, including 400 during a baseline period and 400 for each of the 3 caloric condition interventions. Results. Providing Black adolescents with any caloric information significantly reduced the odds of SSB purchases relative to the baseline (odds ratio [OR] = 0.56; 95% confidence interval [CI] = 0.36, 0.89). When examining the 3 caloric conditions separately, the significant effect was observed when caloric information was provided as a physical activity equivalent (OR = 0.51; 95% CI = 0.31, 0.85). Conclusions. Providing easily understandable caloric information—particularly a physical activity equivalent—may reduce calorie intake from SSBs among low-income, Black adolescents. The consumption of sugar-sweetened beverages (SSBs), which include soda, sport drinks, energy drinks, and fruit drinks, has been associated with adolescent obesity 1 and is highest among minority and lower-income adolescents, accounting for approximately 15% of their total daily intake. 2 For example, Black adolescents consume roughly the equivalent of 2 cans of soda daily. 2 Mounting evidence strongly supports limiting the intake of SSBs to improve energy balance, primarily because calories in liquid form may be less well compensated than are calories in solid form. 3–5 In other words, the average adolescent does not eat fewer calories from solid foods to account for calories consumed from liquids. People generally underestimate the number of calories in the foods they consume. 6 A recent study asking participants to estimate the caloric content of 9 restaurant entrées found that 90% underestimated the caloric content of less healthy items by an average of more than 600 calories. 6 Although initiating and maintaining behavior changes on the basis of calorie information is theoretically a difficult and complex process, 7 there is some empirical evidence suggesting that consumer choices can be markedly affected by information. 8,9 For instance, 1 study found that when consumers are presented with calorie information they choose the high-calorie items approximately one third less often, 6 and another study found that when individuals are exposed to calorie information at the point of purchase, they buy food with fewer calories. 10 However, a recent systematic review of the broader literature suggests that the effect of caloric information on food consumption and purchases is weak or inconsistent. 11 This finding may be related to how caloric information was presented. An important deficit shown in the literature, which may help improve the effectiveness of calorie-posting initiatives aimed at reducing caloric intake, is identifying the most effective mode for presenting consumers with calorie information. Most efforts have focused on absolute caloric information (i.e., calorie count). For example, the Patient Protection and Affordable Care Act requires fast food restaurants to provide “clear and conspicuous” caloric information on menu boards beginning in mid-2012. In April 2011, the Food and Drug Administration invited public comment on 2 sets of proposed regulations that would ensure calorie labeling on menus and menu boards in chain restaurants, retail food establishments, and vending machines with 20 or more locations. Currently the law remains ambiguous about how those calories must be reported. 12 This lack of concrete guidelines may actually create an opportunity to improve the effectiveness of caloric information on purchasing behavior, particularly among groups at the highest risk for obesity. There are several reasons providing consumers with relative caloric information may be more desirable than providing them with absolute caloric information. Absolute caloric information requires consumers to translate the information into interpretable equivalents—a task made more challenging by low levels of nutritional literacy and numeracy, which are highest among low socioeconomic status and minority groups 13–15 Information-based interventions that require less mental processing may be more successful than are information-based interventions requiring greater computation or comprehension effort. 16 Moreover, presenting relative caloric information in terms of its effect (i.e., minutes of running required to burn off a can of soda) may have a greater effect on food purchasing behavior. There is a large body of research suggesting that unfavorable information is more persuasive to consumers. 17 We examined whether providing caloric information about SSBs significantly reduces the volume of SSB purchases among Black adolescents and tested whether varying forms of caloric information on SSBs differently affects the volume of SSB purchases. We hypothesized that providing caloric information in an easily understandable format would reduce adolescent purchases of SSBs. In particular, we hypothesized that relative caloric information (i.e., percentage daily value or physical activity equivalent) would have a larger effect on SSB purchases than would absolute calorie information and that providing consumers with relative caloric information in the form of physical activity equivalents would have a larger impact on SSB sales than would providing relative caloric information in the form of percentage daily value. To our knowledge, no other study has evaluated potentially more effective modes for communicating caloric information about SSBs to adolescents at high risk for obesity and SSB consumption.
