Perceived healthiness of food items and the traffic light front of pack nutrition labelling: choice-based conjoint analysis and cross-sectional survey.

Despite a lack of knowledge about the recommendations underpinning the TLL criteria, decisions made by participants concerning the healthfulness of food products were significantly influenced by sugar content. TLL appears to guide consumer beliefs in the absence of deep knowledge. The dominance of sugar in decision making is unsurprising in the current public health climate.