IMPACT OF THE NEW ZEALAND HEALTH STAR RATING SYSTEM: RCT RESULTS AND EVALUATION OF ROLL-OUT

Background: Interpretive, front-of-pack (FOP) nutrition labels may encourage healthier food choices by consumers and healthier reformulation of foods by industry. Objective: We aimed to evaluate the effects of the Health Star Rating (HSR), a voluntary interpretive FOP labelling system on (1) consumer food choices, and (2) industry food reformulation. Design: Study 1. In a parallel-group randomized controlled trial, we enrolled household shoppers across New Zealand who owned smartphones and were aged >18 y. Participants were randomly assigned to receive either Traffic Light Labels (TLL), HSR, or a control [Nutrition Information Panel (NIP)]. Smartphone technology allowed participants to scan barcodes of packaged foods and receive allocated labels on their smartphone screens. The primary outcome was the mean healthiness of all packaged food purchases, measured using the Food Standards Australia New Zealand Nutrient Profiling Scoring Criterion (NPSC). Study 2. Annual surveys of packaged food labelling and composition were undertaken in supermarkets before and after adoption of HSR in New Zealand i.e. 2014 to 2016. Product data were linked with nationally representative household food purchasing data to obtain estimates of effects weighted by annual purchasing volumes. Outcomes assessed were uptake HSR by food group; composition of products displaying HSR compared with unlabelled products; and composition of products displaying HSR labels in 2016 compared with their composition prior to the introduction of HSR. Results: Study 1. 1357 eligible shoppers were randomly assigned to TLL (n = 459), HSR (n = 443), or NIP (n = 455) labels. There was no significant difference in the mean transformed NPSC scores (healthiness) for the TLL group compared with the NIP group (P = 0.60), or for HSR group compared with NIP (P = 0.12). However, in a per-protocol analysis of participants who used the labelling intervention more often than average (n = 423, 31%), those assigned to TLL and HSR had significantly better NPSC scores than those assigned to NIP (P = 0.04 and 0.01 respectively). Study 2. Two years after adoption of the voluntary system, 5.3% of packaged foods surveyed displayed HSR labels (7.2% weighted by annual purchase volumes). Food groups with highest rates of uptake were cereals, convenience foods, packaged fruit and vegetables, sauces and spreads, and 'other' products (predominantly breakfast beverages). Products displaying HSR labels had significantly lower mean