Objective:‘Traffic-light’ nutrition labelling has been proposed as a potential tool for improving the diet of the population, yet there has been little published research on the impact of traffic-light nutrition labelling on purchases in a supermarket environment. This study examined changes to online consumer food purchases in response to the introduction of traffic-light nutrition information (TLNI).
Methods: The study consisted of a 10-week trial in a major Australian online grocery store. For the duration of the trial TLNI in the form of four colour-coded indicators representing the products’ relative levels of fat, saturated fat, sugar and sodium content, was displayed on the product listing page of 53 of the retailer's own-brand products in five food categories (milk, bread, breakfast cereals, biscuits and frozen meals). The changes in sales before and after the introduction of TLNI were examined both within the intervention store and in a comparison store.
Results: TLNI had no discernible impact on sales, with the change in sales in the intervention store corresponding to changes in sales in the comparison store. No relationship was observed between changes in sales and the relative healthiness of products.
Conclusion and implications: This limited, short-term study found no evidence to support the notion that TLNI is likely to influence behaviour change. Further research is needed to examine the impact of providing TLNI in different contexts, for a longer duration and on more products, with and without complementary awareness and information campaigns.