The influence of physical characteristics on the resting energy expenditure of youth: A meta-analysis.

Objective To examine the literature on resting energy expenditure (REE) of youth and determine the influence of age, sex, BMI, and body composition on REE. Methods A literature search was conducted using PubMed, BIOSIS Previews, NTIS, EMBASE, MEDLINE, and Pascal databases for studies with data on resting metabolic rate, REE, resting oxygen uptake (or VO₂) in healthy children, youth, or adolescents (age = 1-18 years). Over 200 publications were identified; sixty-one publications met criteria and were included in the meta-analyses, resulting in 142 study population estimates (totaling 5,397 youth) of REE. Results Pooled mean was 1414 kcal·day⁻¹ with a significant and moderate-to-high between-study heterogeneity [ Q(140) = 7912.42, P < 0.001; I² = 98.97%]. A significantly greater ( P < 0.001) pooled mean kcal·day⁻¹ was estimated for studies with male participants (1519 kcal·day⁻¹) comparing to studies with female participants (1338 kcal·day⁻¹). Age, height, and body mass resulted in the highest R² of 86.4 for males and 83.9% for females. Fat free mass and body mass index (BMI) did not improve total R². Conclusions These data suggest that using a linear equation including age, height, and body mass to estimate REE based on kcal·day⁻¹ is more accurate than estimates based on body mass kcal·kg⁻¹·h⁻¹. Further, if kcal·kg⁻¹·h⁻¹ is used, including a quadratic component for the physical characteristics improves the predictive ability of the equation. Regardless of the metric, separate equations should be used for each sex. [ABSTRACT FROM AUTHOR]