Statistical analysis
Data were analysed using IBM SPSS v28 (IBM, Armonk, NY, USA, 2021). Descriptive analyses on participants characteristics were conducted. For each food, data were excluded if participants reported that they did not consume a particular food item. Reported perceived portion size norms from two methods were compared using cross-classification and intra-class correlation coefficients (ICC, two-way mixed model, average measure). Data were classified as a correct match (described as selecting the same image option as the real food), an adjacent match (described as selecting the portion size image one option away from that selected for the real food option), or gross mismatch (described as selecting the portion size image four or more options away from that selected for the real food option) [