Children's dietary reporting accuracy over multiple 24-hour recalls varies by body mass index category

This secondary analysis investigated the influences of body mass index (BMI) category and sex on reporting accuracy during multiple 24-hour dietary recalls. On 3 occasions, each of 79 children (40 girls; 39 boys) was observed eating school meals and then interviewed the next morning about the previous day's intake, with 25 days or more between any 2 consecutive occasions for a child. Using age/sex BMI percentiles, we categorized 48 children as having a healthy weight (≥5th but <85th percentile), 14 as at risk of being overweight (≥85th but <95th percentile), and 17 as overweight (≥95th percentile). A repeated-measures analysis was conducted for each of 5 outcomes (number of items observed eaten, number of items reported eaten, omission rate, intrusion rate, and total inaccuracy). For items observed, the BMI Category × Trial interaction was marginally significant (P = .079); over trials, this outcome was stable for children with a healthy weight, decreased and stabilized for children at risk of being overweight, and stable and decreased for overweight children. This outcome was greatest for overweight children and least for children with a healthy weight (P = .015). For items reported, no significant effect was found. For omission rate (P = .028) and intrusion rate (P = .083), the BMI Category × Trial interaction was significant and marginally significant; over trials, both decreased for children with a healthy weight, decreased and stabilized for children at risk of being overweight, and increased and stabilized for overweight children. Total inaccuracy decreased slightly over trials (P = .076); this outcome was greater for boys than for girls (P = .049). The results suggest that children's dietary reporting accuracy over multiple recalls varies by BMI category. Validation studies with adequate samples for each BMI category, sex, and race are needed.