Time Over Money? A Novel System to Influence Snack Machine Choices

Environmental interventions that address the high availability of unhealthy snacks in the environment are needed to prevent a large projected increase in the incidence of obesity and cardiometabolic disease in the U.S. Prior studies from the investigators group and others suggests that the human preference for immediate gratification from food drives dietary overconsumption, but this knowledge has not yet translated to more effective dietary intervention strategies. This project tests whether a novel snack vending machine system that uses brief time delays to reduce the immediacy of reward from unhealthy snacks will improve the healthfulness of snack choices. This study uses an experimental design to compare brief time delays, two forms of 25% differential pricing, and time delays combined with both forms of 25% differential pricing on their ability to increase purchasing of healthy snacks. Test machines will be placed in existing, high-volume vending locations, and each of these five experimental conditions will run for roughly four weeks. Additionally, baseline purchasing under no intervention will be monitored for four weeks before and four weeks after the five experimental conditions. Specific Aim 2 compares the effects of these five interventions against baseline on the proportion of total vending sales from healthy snacks. Specific Aim 3 tests whether time delays or differential pricing harm overall vending machine sales in the test machines. This study not only tests a compelling theory about the effects of time delays and immediate reward on food choice, but evaluates the efficacy and feasibility of a novel intervention to improve the healthfulness of snack choices in worksites, schools, and other settings.