Validity of the BodyGem calorimeter and prediction equations for the assessment of resting energy expenditure in overweight and obese Saudi males

ABSTRACT

To assess the accuracy of resting energy expenditure [REE] measurement in a sample of overweight and obese Saudi males, using the BodyGem device [BG] with whole room calorimetry [WRC] as a reference, and to evaluate the accuracy of predictive equations. Thirty-eight subjects [mean +/- SD, age 26.8 +/- 3.7 years, body mass index 31.0 +/- 4.8] were recruited during the period from 5 February 2007 to 28 March 2008. Resting energy expenditure was measured using a WRC and BG device, and also calculated using 7 prediction equations. Mean differences, bias, percent of bias [%bias], accurate estimation, underestimation and overestimation were calculated. Repeated measures with the BG were not significantly different [accurate prediction 81.6%;%bias 1.1 +/- 6.3, p>0.24] with limits of agreement ranging from +242 to-200 kcal. Resting energy expenditure measured by BG was significantly less than WRC values [accurate prediction 47.4%;%bias 11.0 +/- 14.6, p=0.0001] with unacceptably wide limits of agreement. Harris-Benedict, Schofield and World Health Organization equations were the most accurate, estimating REE within 10% of measured REE, but none seem appropriate to predict the REE of individuals. There was a poor agreement between the REE measured by WRC compared to BG or predictive equations. The BG assessed REE accurately in 47.4% of the subjects on an individual level