The impact of the eco-score and the co-presence of Nutri-Score on sustainable food identification by consumers

Eco-labelling is a way to transparently communicate a product's environmental impact. A universal Eco-Score is under debate, and it remains unclear which form of eco-labelling best supports consumers in identifying sustainable food products, especially in combination with the Nutri-Score. The effectiveness of the Eco-Score on sustainability identification was assessed in two online choice tests (n = 1201, n = 938), by assessing: 1) Eco-Score vs. no label 2) the label design (letter vs. traffic light), 3a) the co-presence of Nutri-Score, and 3 b) similarity versus opposition between Nutri- and Eco-Scores. Results show that without Eco-Score, the overall mean correctness score was 52 % (the change rate of selecting the most sustainable food out of two). With Eco-Score, this improved to 72 % (p < 0.001). The single-letter version slightly outperformed the traffic light version (p = 0.018), particularly among lower-educated respondents. The co-presence of Nutri-Score reduced correct identification slightly (by 5 %), but only when the two scores showed opposite directions (p < 0.001). In conclusion, consumers benefit from a sustainability label to make informed food choices. The simpler letter format is at least as effective as the traffic light version. Although conflicting Nutri-Scores may slightly reduce sustainability identification, the overall positive effect of the Eco-Score remained strong. Adding a sustainability label like the Eco-Score alongside Nutri-Score offers complementary guidance on both health and environmental impact.