Validation of Photography for Determining Food Intakes of High School Students

Abstract

PurposeTo determine if photography is a reliable data collection tool for measuring the food intakes of high school students who participate in the National School Lunch Program (NSLP). Secondly, to compare the energy and macronutrient content of the NSLP meals with meals eaten when not at school.MethodResearchers visited one high school in Illinois and measured the amounts of food consumed by the students using photographs of before and after food trays and weighed food wastes for comparisons. Three researchers not involved with the weighing of the food wastes, estimated the percentage wastes from the photographs. Estimated percentage wastes were converted into gram amounts by using the actual gram weight of the food items served. Actual wastes were weighed and compared with the estimated gram wastes. Students completed a demographic questionnaire and a three day food record which was used to determine the contribution of calories and macronutrients consumed when not at school. Twenty‐two students from grades 9‐12 participated in this pilot study, mean age was 16.41±1.30.Results High inter‐rater reliability was found for estimated and actual gram amounts of food consumed (r= 0.957, p<0.001). Paired samples t‐test of calories and macronutrients indicated significant differences (p<0.05) for meals eaten when not at school with those provided by the NSLP lunch meal. Overall, the NSLP meals provided fewer calories and macronutrients.ConclusionPhotography can be used to determine the food consumption of the NSLP participants in future studies. Contrary to earlier studies, the NSLP meals provided fewer calories and macronutrients than did the meals eaten when not at school. Future studies using a larger sample size are needed.