Effects of front-of-pack labels on the nutritional quality of supermarket food purchases: evidence from a large-scale randomized controlled trial

TLDR

In-store surveys suggest that Nutri‑Score’s ability to attract attention and help shoppers rank products by nutritional quality may explain its performance. The study examined whether four front‑of‑pack nutrition labels improve food purchases in real‑life grocery shopping by applying 1.9 million labels to 1,266 products across 60 supermarkets and analyzing 1,668,301 purchases with the FSA nutrient‑profiling score. The authors applied 1.9 million labels to 1,266 products in 60 supermarkets and assessed the nutritional quality of 1,668,301 purchases with the FSA nutrient‑profiling score. Effect sizes were 17 times smaller than in laboratory studies, and only the Nutri‑Score label increased purchases of top‑third‑nutrition foods by 14%, improving the overall basket quality by 2.5 % (−0.142 FSA points); its performance rose with category‑quality variance but not mean.

Abstract

Abstract To examine whether four pre-selected front-of-pack nutrition labels improve food purchases in real-life grocery shopping settings, we put 1.9 million labels on 1266 food products in four categories in 60 supermarkets and analyzed the nutritional quality of 1,668,301 purchases using the FSA nutrient profiling score. Effect sizes were 17 times smaller on average than those found in comparable laboratory studies. The most effective nutrition label, Nutri-Score, increased the purchases of foods in the top third of their category nutrition-wise by 14%, but had no impact on the purchases of foods with medium, low, or unlabeled nutrition quality. Therefore, Nutri-Score only improved the nutritional quality of the basket of labeled foods purchased by 2.5% (−0.142 FSA points). Nutri-Score’s performance improved with the variance (but not the mean) of the nutritional quality of the category. In-store surveys suggest that Nutri-Score’s ability to attract attention and help shoppers rank products by nutritional quality may explain its performance.