Development and Validation of a Photographic Method to Use for Dietary Assessment in School Settings

ObjectiveTo develop and validate a photographic method aimed at making assessment of dietary intake in school canteens non-obstrusive, practical and feasible.MethodsThe study was conducted in two elementary schools representing two different school canteen systems; main dish being served by canteen staff (Iceland), and complete self-serving (Sweden). Food items in serving and leftovers were weighed and photographed. Trained researchers estimated weights of food items by viewing the photographs and comparing them with pictures of half and full reference portions with known weights. Plates of servings and leftovers from 48 children during five school days (n = 448 plates) and a total of 5967 food items were estimated. The researchers’ estimates were then compared with the true weight of the foods and the energy content calculated.ResultsWeighed and estimated amounts correlated across meals both in grams and as total energy (0.853–0.977, pConclusionsThe photographic method provides acceptable estimates of food and energy intake in school canteens. However, greater accuracy can be expected when foods are served by canteen staff compared with self-serving.研究目的：本研究旨在开发并验证一种摄影评估方法，实现学校食堂膳食摄入评估的无干扰性、实用性与可行性。 研究方法：本研究在两所采用不同供餐模式的小学开展：其一为食堂工作人员分发主餐（冰岛），其二为完全自助取餐（瑞典）。研究人员对供餐餐盘与剩余食物进行称重并拍摄照片。经过培训的研究人员通过查看照片，并与已知重量的半份、整份参考食物图片进行比对，估算食物重量。本次研究共对5个上学日内48名儿童的供餐餐盘与剩余餐盘（共448份）以及总计5967个食物条目进行了重量估算。随后将研究人员的估算值与食物实际重量及计算得到的能量含量进行对比分析。 研究结果：各餐次的称重值与估算值在重量（克）及总能量层面均呈现显著相关性（相关系数区间为0.853–0.977，p）。 研究结论：该摄影评估方法可对学校食堂的食物摄入与能量摄入作出可接受的估算。不过，相较于自助取餐模式，当由食堂工作人员分发食物时，该方法的估算精度可得到进一步提升。