Effects of health star labelling on the healthiness of adults’ fast food meal selections: An experimental study

The addition of Health Star Rating (HSR) labelling to menus at fast food outlets is feasible, however how this would impact consumer menu selection remains unclear. The aim of this study was to test whether the addition of HSR labelling to kilojoule (kJ) labelling on menus at fast food outlets would prompt consumers to select healthier meals. Using a between-subjects experimental design, 1007 adults aged 18–49 were allocated to one of four menu labelling conditions: (i) no labelling; (ii) kilojoule labelling; (iii) HSR labelling; and (iv) kilojoule + HSR labelling. Respondents were presented with their assigned menu online and instructed to select an evening meal as they would at a fast food restaurant. The main analyses tested differences by menu labelling condition in the total mean kilojoule content and Nutrient Profiling Score (NPS) of respondents’ evening meal selections using one-way ANOVA. The mean kilojoule content of meals did not differ significantly by menu labelling condition. However, respondents in the kilojoule + HSR labelling condition selected healthier meals (lower mean NPS) than those who viewed menu boards with kilojoule labelling only (M = 2.88 cf. M = 3.78, p = 0.046). In addition, in a post hoc per-protocol analysis of respondents who reported using menu labelling to assist their meal selection, respondents shown kilojoule + HSR menu labelling selected meals with a significantly lower kilojoule content compared to those shown HSR labelling only (4751 kJ cf. 5745 kJ, p = 0.038). Findings provide evidence that adding HSRs to kilojoule labelling on menu boards at fast food outlets has the potential to assist adults to make healthier evening meal selections.