Fourth graders' reports of fruit and vegetable intake at school lunch: does treatment assignment affect accuracy?

Dietary interventions with children often use self-reported data to assess efficacy despite that objective methods rarely support self-report findings in validation studies. This study compared fourth graders' self-reported to observed lunch fruit and vegetable intake to determine if the accuracy of self-reported intake varied by treatment condition.

Matched randomized follow-up design examined three treatment groups (high and low intensity interventions and control) post-intervention.

Three hundred seventy-nine middle-school children participating in a randomized controlled trial of a school-based fruit and vegetable intervention were observed during school lunch one day and asked to recall intake the following day.

Food items were coded as: "match," "omission," or "intrusion." Students were classified as accurate if all food items matched, otherwise inaccurate. Matched foods' portions were compared for accuracy. Servings were computed for total fruit and vegetable intake.

Accuracy for fruits and vegetables were compared in separate analyses and tested for multiple potential associates: treatment condition, sex, race, body mass index, subsidized meal eligibility, school district, fruit/vegetable availability, age, and test scores. Fitted multivariable regression models included variables found to be significant in univariate or chi(2) analyses.

Variables found to be significant for fruit item accuracy were availability at lunch, body mass index, and subsidized lunch eligibility. For vegetable item accuracy, availability at lunch was significant. No differences were found for food portions or for efficacy of the intervention between the two methods of dietary data collection: observation and self-report.

Condition assignment did not bias recalled fruit and vegetable intakes among fourth graders.