Differences in Resting Metabolic Rate between BodyMetrix™ and Indirect Calorimetry in South African Adults

ABSTRACT

Accurate assessment of resting metabolic rate (RMR) is necessary for calorie-based recommendations in diet and exercise training interventions. BodyMetrix™ is an ultrasound-based device that provides an estimate of RMR based on body composition, but has not been proven valid or reliable. Therefore, we evaluated the agreement between Katch–McArdle prediction equation used by BodyMetrix™, with indirect calorimetry, Harris–Benedict, WHO, and Sabounchi prediction equations of RMR. In total, 32 men and 22 women were measured for body composition via BodyMetrix™ and RMR via indirect calorimetry. All prediction equations demonstrated significantly lower RMR values (p < .001) relative to indirect calorimetry. Katch–McArdle equation strongly correlated with other prediction equations (p < .001), and had a moderate (r = .658, p < .001) correlation with indirect calorimetry. There was a tendency toward underestimation for obese individuals. Therefore, we suggest that estimates from BodyMetrix™ may be used as a relative, rather than an absolute measure of RMR.

KEYWORDS:

• Resting metabolic rate
• basal metabolic rate
• BodyMetrix™
• indirect calorimetry