'Threat' of Jogging More Convincing Than Calorie Count in Curbing Soda Sales: Study

Sodas, sports drinks, and other sugar-sweetened beverages appear less tempting to consumers when labels show caloric information in terms of minutes of jogging rather than as absolute calorie counts, new research from two leading public health universities suggests.

Researchers monitored adolescents at four corner stores in West Baltimore, where low-income residents are at especially high risk for obesity partially tied to increased soda consumption. For six months last year, they posted one of three different signs near beverage cases in each store, converting a bottle of soda to a calorie count (250 calories), a percentage daily value (10%), or the amount of jogging time it would take to burn off the drink (approximately 50 minutes). The researchers intentionally used jogging, rather than more enjoyable physical activities such as basketball or dancing, because of their belief that unfavorable information is more persuasive to consumers.

As a result of the signs, teenagers were 40% less likely overall to buy sugar-sweetened beverages, rather than juice or water, than they were when no information other than the manufacturer label was available. In stores that displayed the jogging signs, they were half as likely to opt for a sugary drink.

“Americans in general and our target population in particular have low levels of nutritional literacy and numeracy. In other words, most people are bad at doing mental calculations and understanding the content of the foods they eat,” said Sara Bleich, lead author of the study and an assistant professor at Johns Hopkins Bloomberg School of Public Health, in an email communication with me. “We were skeptical that the current standard of presenting calories in chain restaurants as calorie counts would be very meaningful among our target population.”

The study, designed jointly with Columbia University’s Mailman School of Public Health, was prompted by a public health measure in the Patient Protection and Affordable Care Act of 2010. Section 4205 of the bill mandates that fast food restaurants, vending machines, and other retail food establishments with 20 or more locations post “prominent, clear, and conspicuous” caloric information beginning in mid-2012.

In an analysis of the need for the mandate, the U.S. Food and Drug Administration wrote that “studies suggest that some or many consumers will not demand calorie information, because the issue of calories often lacks salience, or relevance, for consumers at the time of purchase and consumption, even though they may experience regret about their decisions at a latter date.”

However, a lack of clarity in the law on how those calories must be reported in most cases has lead to establishments providing absolute caloric information (calorie count) rather than relative caloric information such as the physical equivalent or effect of consuming a specific food or beverage, the researchers claim.

“We felt it was important to explore the most effective strategies for presenting caloric information to consumers, especially since the regulation is somewhat ambiguous as to how those calories should be reported,” Bleich said. She suggested that the significant decline in sugar-sweetened beverage purchases among black adolescents as a result of tying consumption to physical exercise would likely mean an even bigger effect among other demographic groups who are more concerned with diet (e.g., more educated, white women).

The results of the study were based on data collected for 1,600 beverage sales by Black adolescents aged 12-18 years, including 400 during a baseline period in which no signs were posted, and 400 for each of the three caloric condition interventions.

Bleich concedes acceptance of the more graphic calorie labeling may be slow among merchants worried about declining soft drink sales, which make a considerable chunk of their revenue. At the outset of the study, a number of stores refused to participate due to lack of water or diet beverages for purchase, or fear that the experiment would negatively affect sales. Acceptance might be especially difficult if a decline in soda sales is not compensated by increased sales of healthier drinks, in which case the stores might introduce cross subsidies by raising prices of sugar-sweetened beverages while lowering prices of juice and water, Bleich said. In addition, public health officials might consider subsidizing the stores.

The study is the first of its kind to examine the impact of different ways of presenting caloric information on purchasing behavior. It will be published in the American Journal of Public Health  next month [read abstract here].