Effects of front-of-package nutrition labelling systems on understanding and purchase intention in Jamaica: results from a multiarm randomised controlled trial

Abstract

ObjectiveTo assess the effects of three different front-of-package labelling (FOPL) schemes on objective understanding and intention to purchase of products, in Jamaica.SettingSupermarkets in Jamaica.ParticipantsAdult supermarket shoppers in Jamaica (n=1206) aged 18 years old or older were included in the study, except for those visually impaired, or unable to give informed consent.DesignMultiarm parallel-group randomised trial.InterventionsParticipants were randomly allocated to one of the three intervention groups or the control group. They were exposed to two-dimensional images of 12 mock-up products presented in random and balanced order. Participants assigned to the intervention groups were exposed to one FOPL scheme: black octagonal warning labels (OWL), magnifying glass high-in single icon (MGG) or traffic-light labelling (TFL). The control group was exposed to the nutrition facts up front.Outcome measuresOR for correctly understanding nutritional information (correctly selecting the least harmful option, correctly identifying sugars, sodium and/or saturated fats found to be in excess) and choosing to purchase the least harmful option (purchase intention), more often.ResultsCompared with the control group, the odds for correctly selecting the least harmful option more often were 107% higher in the OWL group (OR 2.07, 95% CI 1.54 to 2.78; p<0.001), whereas the MGG (1.18, 95% CI 0.89 to 1.57; p=0.24) and the TFL (1.13, 95% CI 0.85 to 1.51; p=0.39) were inefficacious in improving such odds. OWL also resulted in the highest odds for correctly identifying a product with excessive amounts of sugars, sodium and/or saturated fats and for deciding to purchase the least harmful option or none of the options.ConclusionsOctagonal warning labels performed best at improving the ability of adult shoppers in Jamaica to understand the nutrition information and at encouraging them to purchase the least harmful option more often.

How Promising Are “Ultraprocessed” Front-of-Package Labels? A Formative Study with US Adults

“…If scanned, this code led participants to a website that explained what a QR code is. Labels were octagon-shaped, since this design has been shown to perform the most consistently at improving consumers' understanding of nutrient content and eliciting behavior change across a range of contexts [56][57][58][59][60]. The nutrient label used a black background with white text, mimicking the design used in countries like Chile and Mexico [44], while the "ultraprocessed" label used a white background with black text to distinguish processing level as a separate product dimension [49].…”