Signage promoting the benefits of healthy snacks and drinks in vending machines may attract more patrons to buy them than offering a price discount, a new study suggests. Called "Health Promotion and Healthier Products Increase Vending Purchases: A Randomized Factorial Trial," the study was published this week in the Journal of the Academy of Nutrition and Dietetics.
Researchers conducted their trial in 28 food and beverage machines on a college campus for five months. They experimented with remerchandising machines with "healthy" options; offering discounts for better-for-you choices; and posting signs promoting attributes like less sugar or fewer calories. They also tried different combinations of these actions.
Prior to the study, the machines were merchandised with standard top-selling chocolates, chips and nut mixes, none of which meet the National Automatic Merchandising Association's Fit Pick nutrition standards.
During the study, all of the top sellers met the nutrition standards, which allow no more than 250 calories, 20g. of sugar and 10g. of fat. They included whole grain Pop-Tarts, Sun Chips, reduced-fat Doritos, Snyder's honey mustard pretzels and baked potato crisps.
Prior to the study, all of the top-selling beverages were sodas: Diet Coke, Coke and Coke Zero. With the experiment, they remained bestsellers, but Dasani water also made the list.
Independently reducing the price of healthier items by 25% did not persuade consumers to buy them. Conversely, both revenue and unit sales fell versus the same five-month period in the previous year. Senior study author Jeannette Ickovics, a public health researcher at Yale University said this came as a surprise.
The researchers had also hypothesized that the combination of all three interventions -- restocking, discounts and signs -- would have the biggest impact on consumers. They found, however, that restocking the machines and posting promotional signs boosted sales more than discounting product did. They also saw different results for snacks versus beverages.
In snack machines, adding healthier selections and discounting them led customers to purchase 460 more units during the study period over the comparable year- earlier period. Revenue increased by $1,039.
In beverage machines that the researchers remerchandised with healthier options and posted signs, sales increased by 204 units. Sales increased only by 66 units in beverage machines that discounted healthy choices in addition to the other two interventions.
The study's authors acknowledged that the limitations of the study include its small size and the possibility that at least some of the shifts in purchases could be attributed to the novelty of new items and not a sustained effort by consumers to buy healthier options.