Using smart card technology to monitor the eating habits of children in a school cafeteria: 1. developing and validating the methodology.

OBJECTIVE: The aim of the study was to test the feasibility of using smart card technology to track the eating behaviours of nearly a thousand children in a school cafeteria. METHODS: Within a large boys’ school a smart card based system was developed that was capable of providing a full electronic audit of all the individual transactions that occurred within the cafeteria. This dataset was interfaced to an electronic version of the McCance and Widdowson composition of foods dataset. The accuracy of the smart card generated data and the influence of portion size and wastage were determined empirically during two 5-day trials. RESULTS: The smart card system created succeeded in generating precise data on the food choices made by hundreds of children over an indefinite time period. The data was expanded to include a full nutrient analysis of all the foods chosen. The accuracy of this information was only constrained by the limitations facing all food composition research, e.g. variations in recipes, portion sizes, cooking practices, etc. Although technically possible to introduce wastage correction factors into the software, thereby providing information upon foods consumed, this was not seen as universally practical. CONCLUSION: The study demonstrated the power of smart card technology for monitoring food/nutrient choice over limitless time in environments such as school cafeterias. The strengths, limitations and applications of such technology are discussed.