Ultra-processed foods are of poor nutritional quality in French consumers' representations; a categorization study of images of food products without information

This study investigated how consumers categorize food according to its nutritional quality and degree of processing through two online questionnaires. Two hundred French consumers used a directed sorting task to categorize 21 images of food products by nutritional quality and degree of processing. The images contained no information about these two characteristics or any other properties. Two multinomial logit regression analyses revealed that (1) without any access to established values for degree of processing or nutritional quality, participants' categorizations of food images closely mirrored these established values; (2) participants' categorization of food products by nutritional quality was also influenced by non-nutritional properties; (3) participants linked nutritional quality to degree of processing in their categorizations. Possible reasons are proposed for this link and the cognitive mechanisms involved, such as a learned association resulting from the overly simple messages conveyed by dietary guidelines, the use of heuristics to overcome the difficulty of estimating the nutritional quality of food products in the absence of information, and the health halo effect.