A Systematic Review of Methods to Assess Children's Diets in the School Context.

To evaluate the impact of school-based nutrition interventions, accurate and reliable methods are needed to assess what children eat at school. The primary objective of this study was to systematically review methodological evidence on the relative accuracy and reliability of dietary assessment methods used in the school context. The secondary objective was to assess the frequency of methods and analytical approaches used in studies reporting in-school dietary outcomes. Three health databases were searched for full-text English-language studies. Twenty-two methodological studies were reviewed. For school meal recalls, the majority of studies (n = 8 of 12) reported poor accuracy when accuracy was measured by using frequencies of misreported foods. However, when energy report rates were used as a measure of accuracy, studies suggested that children were able to accurately report energy intake as a group. Results regarding the accuracy of food-frequency questionnaires (FFQs) and food records (FRs) were promising but limited to a single study each. Meal observations offered consistently good interrater reliability across all studies reviewed (n = 11). Studies reporting in-school dietary outcomes (n = 47) used a broad range of methods, but the most frequently used methods included weighed FRs (n = 12), school meal recalls (n = 10), meal observations by trained raters (n = 8), and estimated FRs (n = 7). The range of dietary components was greater among studies relying on school meal recalls and FRs than among studies using FFQs. Overall, few studies have measured the accuracy of dietary assessment methods in the school context. Understanding the methodological characteristics associated with dietary instruments is vital for improving the quality of the evidence used to inform and evaluate the impact of school-based nutrition policies and programs.