sign or discount? the effects of various price and promotion strategies on food purchases in a randomized controlled web-based supermarket trial

Objective: To examine the effectiveness of pricing strategies and promotion signs to stimulate healthier food purchases. Methods: A randomized controlled factorial design with three levels of price reduction (10%; 25%; and 50%) and three types of signs ('special offer', 'healthy choice' and 'special offer & healthy choice') on healthy foods was used. N=109 participants completed the experiment by conducting a typical shop for their household for one week at a web-based supermarket. Data were collected in the Netherlands in 2010 and analyzed using analysis of covariance. Results: Participants receiving a 50% price discount purchased more healthy foods for their household for one week than the 10% discount (+8.7 items; 95%CI=3.8-13.6) and the 25% discount group (+7.7 items; 95%CI=2.74-12.6). However, the proportion of healthy foods was not significantly higher; participants purchased the healthy foods in addition to other items. There were no significant differences in food purchases between conditions with the different promotion signs and there was no significant interaction between the effects of the signs and the discounts. Conclusion: Price discounts were effective in stimulating the number of healthy food items purchased. This effect was not influenced by displaying signs promoting the healthiness or special offer of the products or a combination of both. The effects of promotion strategies need however more careful examination in different settings. 161 Chapter 9 Introduction In the quest for improving dietary behaviours, there is increasing recognition that alongside interventions focused on individual behaviour change, interventions in the food environment may be required