Background: Implementation of strategies that reduce global consumption of drinks high in free sugar (e.g. soft drinks, energy drinks, fruit juice) are desperately needed in countries such as Australia where consumption is high. This study aimed to examine the effect of exposure to a warning label, independently and in conjunction with a Health Star Rating (HSR) icon, on the selection of commercially available beverages in an in-person app store experiment that had real decision-making stakes.
Method: 511 young adults participated in the study via laptops set up on-campus with a newly developed online convenience store app that sold 10 commercially available cold beverages (5 sugar-sweetened beverages [SSBs], 1 100% fruit juice, 2 artificially-sweetened beverages [ASBs] and 2 waters). Participants were guided through the app to select a beverage 3 times, one of which was randomly selected for them to keep after completing a brief questionnaire. The experimental manipulation was comprised of changing the drink display to show on-bottle warning labels on SSBs and 100% fruit juice in rounds 2 and 3, and HSRs on all drinks in round 3.
Results: Adding warning labels to beverages in round 2 corresponded with a significant decrease in the selection of SSBs (p<0.001) and 100% fruit juice (p<0.05) and a significant increase in the selection of ASBs and waters (p<0.001). Adding a HSR icon in conjunction with warning labels in round 3 corresponded with a further, albeit non-significant, reduction in SSB selection, but a statistically significant increase in 100% fruit juice selection (p<0.001) from round 2 to 3.
Conclusions and implications: Results indicate that warning labels can be used in conjunction with HSR icons to discourage SSB beverage consumption in settings with real decision-making stakes. However, further research on non-SSB drink selection preferences following exposure to both warning labels and HSR icons is warranted.