Abstract
OBJECTIVES: To date, no real-world pricing intervention has simultaneously increased prices of unhealthy foods and decreased prices of healthy foods in a retail food store or has attempted to assess the relative change in prices needed to increase healthier food purchases. This study aims to test different pricing manipulation strategies for healthy and unhealthy foods in a community grocery store. METHODS: A nine-month price manipulation intervention will be conducted in a community grocery store in Baltimore City, DMG Foods. We will select multiple products representing healthy and unhealthy versions of the same food type (e.g., 2 brands of 100% whole wheat bread and 2 brands of white bread) for over 100 foods and beverages, and randomize versions to receive the pricing manipulation. Monthly itemized sales data from DMG Foods will be used to evaluate the extent of pricing changes on sales. Difference in difference analyses will be used to assess the difference in the change of sales between price manipulated foods and similar non-manipulated foods from baseline to end of each intervention period. Customer purchasing data (n = 100) will be collected using the DMG Foods electronic loyalty card system. Healthy Eating Index and FAST (Food Assortment Scoring Tool) scores will be calculated to assess healthfulness of food purchases by consumers. Paired t-tests will be used to assess statistically significant changes in healthfulness scores pre- and post-interventions. RESULTS: The impact of pricing interventions on store sales will be evaluated through the number, caloric content, and healthiness/unhealthiness of items sold, revenue, and gross profit. Ideal pricing strategies that will lead to substitution of healthier choices for less healthy choices will be identified. Changes in nutritional quality of total food purchased by consumers, ratio of healthy/unhealthy foods purchased, and substitution of promoted/discouraged items by the intervention will be assessed. CONCLUSIONS: This will be the first study to examine the impact of simultaneous increases and decreases of pricing on retail food store sales and customer purchasing of healthy/unhealthy foods. The results of this study will be used to inform national programs and policies aimed at improving diet and prevention of obesity and chronic disease. FUNDING SOURCES: Johns Hopkins Department of International Health.