Can We Predict Underreported Energy Intake And Evaluate Nutritional Status Accordingly?

Abstract

Energy expenditure (EE) was measured using the doubly labeled water (DLW) technique in this cross-sectional study of children with equal numbers of blacks and whites; boys and girls; with a wide range of body weights. Food records were kept for the entire 8-day study with nutritionists monitoring school lunch food consumption to improve the accuracy of parent-assisted, student-kept records. Reported energy intake (REI) and other nutrient information were derived from these records. Data were analyzed using ANOVA with the general linear models procedure. Post hoc t-tests were used to determine differences between means. Underreporting (EE - REI) was significant for black children (950±200kcal; p=0.0002). and there was a tendency for underreporting in white children (320±160kcal; p=0.0626). When students were divided into tertiles of body fat, the fattest group had the greatest underreporting of energy intake (1040±240 kcal; p<0.001). We evaluated data using three assumptions: (1) that only energy and micronutrients other than protein were underreported, (2) that the children could not identify portion sizes accurately and consequently, the composition of the diet should be increased proportionally to the percentage of the underreporting, and (3) that specific foods are underreported or eliminated and the potential incorporation of this “forgotten” food into the diet needs to be considered in the evaluation of nutritional status. Using assumption 1, intakes of calcium, magnesium, zinc, and vitamin A for the black students were below 70% of the RDA. Under assumption 2, intakes improved for black children with the exception of calcium which was still less than 75% of the RDA. For assumption 3, data looked similar to those described in assumption 1 and in this scenario vitamin A and calcium continued to be low. It is possible that the actual %RDA for blacks is more in line with whites when the additional 33–41% of energy is accounted for in the diet. Depending on what was not reported by the child, the macronutrient (and consequently the micronutrient) composition of the diet may differ significantly from that reported here. These data support the hypothesis that energy intake is consistently underreported in the obese and in blacks and is evident in pre-adolescent youth. While micronutrient status was of some concern in the black population, a general increase relative to the percentage of underreporting is only warranted if the type of misreporting can be identified. Our three assumptions for the evaluation of data with respect to the underreports shed a different light on the subject and will help to direct our future research endeavors to improve dietary assessment methods in adolescent populations. Efforts to confirm one of the above assumptions would greatly assist in developing useful guidelines for evaluation of nutrient intake in overweight and other sub-populations.