Effects of dual front-of-pack nutrition and sustainability labelling on consumer understanding, purchase intentions, food choices and willingness to pay: A systematic literature review

Dual front-of-pack (FoP) labelling (i.e., presence of both nutrition and sustainability labels) can guide consumers towards healthier and more sustainable food choices. Despite growing interest, evidence on behavioural outcomes remains limited. This study aimed to review existing literature to understand the effects of dual FoP labelling on consumer behaviour. We searched seven databases for experimental studies published until May 2024 that assessed dual front-of-pack labels as interventions. Eligible studies measured the following outcomes: objective understanding, purchase intention, food choice, and/or willingness to pay (WTP). Risk of bias was assessed using the RoB 2 tool. Seven studies examined five nutrition and five sustainability labels, with three reporting on purchase intention, three on food choice, and one on WTP. None of the studies assessed objective understanding. Risk of bias assessment rated five studies as high quality, one moderate, and one low. Five studies testing congruent dual labelling (positive nutrition & sustainability scores) using interpretive formats (e.g., warning labels, Nutri-Score, Eco-Score) reported favourable effects of dual labelling. Two studies assessing congruent text-based or certification labels showed unfavourable outcomes. Incongruent labelling (positive nutrition & negative sustainability, and vice versa) produced mixed results, suggesting conflicting information may confuse consumers. Understanding how consumers respond to combined nutrition and sustainability information is essential for transitioning to healthy and sustainable food systems. This review shows that dual labelling can influence choices, but its effectiveness depends on label format and message framing, highlighting the need for careful design to avoid unintended effects and support informed decision-making.