The impact of calorific screening thresholds and weight status when validating UK supermarket transaction records in dietary evaluation: FIO-STRIDE

Objective To assess whether calorific screening thresholds improved the agreement between objective consumer purchase data, from supermarket transaction records, and self-reported dietary intake, from a Food Frequency questionnaire (FFQ), for people living with (PLWOw/Obwith) and without (PLWOw/Obwithout) overweight/obesity. Design Participants were recruited across a one-year period (1st June 2020 – 31st May 2021). Six screening thresholds were employed, using the estimated number of calories purchased for the individual, to filter participant data. Bland-Altman analyses were compared between PLWOw/Obwith and PLWOw/Obwithout for energy, sugar, total fat, saturated fat, protein and sodium. Setting Partnered with a large UK retailer. Participants Participants (N=1788) were recruited via the retailer’s loyalty card customer database. Participants with completed FFQs, shared transaction records, height, weight and household composition data were included for analysis (N=642). Results Agreement was found between objective purchase data and self-reported dietary intake at ≥1000 Kcal/day (energy, sugar, total fat and saturated fat) and ≥1500 Kcal/day (protein and sodium). PLWOw/Obwith consumed greater energy (19%), sugar (36%), total fat (22%) and saturated fat (25%) than they were estimated to have purchased at the retailer. PLWOw/Obwithout only consumed greater sugar (19%). Conclusions The application of screening thresholds based on estimated individual calories purchased may provide a valuable preprocessing step within the analysis of consumer purchase data, allowing agreement to be found for absolute nutrient values. Differences in bias between PLWOw/Obwith and PLWOw/Obwithout show that insights into purchase and consumption patterns can be identified using consumer purchase data.