Comparison of self-reported, measured, metabolizable energy intake with total energy expenditure in overweight teens

Abstract

Background: The accuracy of dietary energy assessment tools is critical to understanding the role of diet in the increasing rate of obesity.

Objectives: The purposes of our study in overweight adolescent boys and girls were 1) to assess the energy reporting bias of diet records against the referent of total energy expenditure (TEE) and 2) to compare the methods of determining energy needs by using measured metabolizable energy intake (MEI) and TEE.

Design: Twenty girls [12-15 y, body mass index (in kg/m2) = 33.0 +/- 5] and 14 boys (12-14 y, body mass index = 27.4 +/- 4) participated in 2- to 3-wk metabolic balance studies. TEE was measured by using doubly labeled water (TEE(DLW)), and MEI was measured by bomb calorimetry of composite daily diet, urine, and fecal collections. Food records were collected before each study.

Results: Food records underreported TEE(DLW) by 35 +/- 20%. Underreporting of energy intake was correlated with all macronutrient intake concentrations (g or kcal) (P < 0.0001). A multiple regression model showed that 86.4% of the variance in underreporting error was explained by dietary fat (g), BMI, and sex. The intrasubject CV was 3.9% for TEE(DLW) and 9.9% for MEI. MEI for weight stability (MEI(wtstb)) averaged 99 +/- 11% of TEE.

Conclusions: The increased underreporting of dietary intake with increasing body weight in teens may explain in part previous reports noting that there has been an increased incidence of obesity, although energy intakes have not appeared to increase. MEI(wtstb) and TEE(DLW) gave similar estimates of energy needs. This trial was registered at clinicaltrials.gov as NCT 00592137.

Trial registration: ClinicalTrials.gov NCT00592137.

FIGURE 1

Mean (±SD) reported energy intake from diet records (solid bars), average weight-adjusted metabolizable energy intake (MEI_wtstb; open bars), and total energy expenditure (TEE) by doubly labeled water (hatched bars) in overweight boys and girls [energy intake (EI) expressed as % of total energy expenditure measured by doubly labeled water (TEE_DLW)]. *Reported energy intake significantly differed from MEI and TEE_DLW by paired t test, P < 0.05. Average weight-adjusted MEI was not significantly different from TEE_DLW as evaluated by paired t tests (P > 0.05).

FIGURE 2

Relation between BMI and underreporting as determined by linear regression (underreporting = BMI, sex, r² = 0.18, P = 0.05). Girls are represented by circles and the dashed line, and boys are represented by squares and the solid line.