A comparison of energy expenditure equations for basal-equivalent activities

Introduction: Resting energy expenditure (REE) represents the largest component of total energy expenditure and is a major contributor to energy balance. Over the past several decades, numerous REE equations have been developed targeted to different population groups. However, the generation of standardized equations for predicting energy expenditure, to be applied to every healthy individual, is still subject to research. Purpose: This study aims to test existing predictive equations for basal energy requirements and based on a comparison of their results and measured values, to determine the most appropriate to the characteristics of the studied group. Methodology: Thirty participants (age 30,37 ± 5,50) performed a sequence of five activities chosen to represent basal, light and moderate intensities. The included three basal-equivalent tasks were analyzed in this study. During each trial, oxygen consumption was measured by a portable metabolic system (K4b2). From a previously developed literature research, equations were selected to estimate energy requirements. Calculations and values obtained from oximetry were compared. Results and Discussion: Retrieved predictive equations were filtered to 21 relevant equations from 15 authors. When observing general results, most participants showed the equation proposed by Korth (based on weight, height, sex, and age) to be the one predicting values with a better approximation to K4b2, followed by the Haaf&Weijs’ equation, based on fat-free mass (FFM). From the individual analysis, Korth’s equation proved to work well for men in most cases and poorly for women. Correspondingly, Haaf&Weijs equation gave better results for females. Specifically, better approximations were obtained within males participants. Finally, the associated deviations from measured values indicate more reliable results than a Level 1 (two with better accuracy than a Level 2) of the assessment approaches, for energy consumption while working, referred in the ISO 8996:2004 standard. Conclusions: Through this study, Korth (based on weight, height, sex, and age) and Haaf&Weijs (based on FFM) equations proved to be the most accurate. As a result, since body composition measurement is not always possible, the equation of Korth is advised for use in a young subjects’ sample with similar overall characteristics to the sample hereby presented. Future studies should be developed to test equations within bigger samples and propose a new regression model that better adapts to the studied population.