Digital photography as a tool to measure school cafeteria consumption

BACKGROUND: Assessing actual consumption of school cafeteria meals presents challenges, given recall problems of children, the cost of direct observation, and the time constraints in the school cafeteria setting. This study assesses the use of digital photography as a technique to measure what elementary-aged students select and actually consume from school cafeteria meals. METHODS: Before and after still digital photographs were taken of labeled trays for every lunch served to elementary students over 4 lunch periods. Two analysts visually estimated the amount of each item consumed from every tray, and those estimates were compared to evaluate interrater reliability. RESULTS: Collection of photographic data was rapid and did not disrupt the busy elementary cafeteria setting. Analysts' estimates of consumption levels of meal components (main and side dishes) were within 10% of each other in 92% of the cases. Only 0.2% of items could not be analyzed due to children playing with food or otherwise obstructed photographs. CONCLUSIONS: Digital photography offers researchers and school food service personnel a highly accurate and cost-effective tool to measure actual consumption of school cafeteria meals. Data collected through this method can be evaluated by simple counts of servings of produce or other food groups or by more detailed analyses of nutritional composition.