Traffic-light labels and financial incentives to reduce sugar-sweetened beverage purchases by low-income Latino families: a randomized controlled trial

Abstract

Objective: The objective of the present study was to test the effectiveness of financial incentives and traffic-light labels to reduce purchases of sugar-sweetened beverages in a community supermarket.

Design: In this randomized controlled trial, after a 2-month baseline period (February-March 2014), in-store traffic-light labels were posted to indicate healthy (green), less healthy (yellow) or unhealthy (red) beverages. During the subsequent five months (April-August 2014), participants in the intervention arm were eligible to earn a $US 25 in-store gift card each month they refrained from purchasing red-labelled beverages.

Setting: Urban supermarket in Chelsea, MA, USA, a low-income Latino community.

Subjects: Participants were customers of this supermarket who had at least one child living at home. A total of 148 customers (n 77 in the intervention group and n 71 in the control group) were included in the final analyses.

Results: Outcomes were monthly in-store purchases tracked using a store loyalty card and self-reported consumption of red-labelled beverages. Compared with control participants, the proportion of intervention participants who purchased any red-labelled beverages decreased by 9 % more per month (P=0·002). More intervention than control participants reduced their consumption of red-labelled beverages (-23 % v. -2 % for consuming ≥1 red beverage/week, P=0·01).

Conclusions: Overall, financial incentives paired with in-store traffic-light labels modestly reduced purchase and consumption of sugar-sweetened beverages by customers of a community supermarket.

Trial registration: ClinicalTrials.gov NCT01990508.

Keywords: Financial incentives; Sugar-sweetened beverages; Supermarket traffic-light labels.

Figures

Figure 1.

Consort flow diagram of participants enrolled in a randomized controlled trial to test the effectiveness of traffic-light labels and financial incentives to reduce sugar-sweetened beverage purchases by low-income families at a community supermarket, Chelsea, MA (April – August 2014).

Figure 2.

Proportion of intervention subjects who purchased any red beverages decreased 9% more per month than control (N = 148), among participants enrolled in a randomized controlled trial to test the effectiveness of traffic-light labels and financial incentives to reduce sugar-sweetened beverage purchases by low-income families at a community supermarket, Chelsea, MA (April – August 2014); *p-value = 0.002 for difference in trends over time in proportion of subjects who purchased any red beverages.