Comparison of energy expenditure estimated by IDEEA and doubly-labelled water in free-living individuals

Energy expenditure (EE) is one of the predictors of weight-loss maintenance in the DiOGenes project. This was measured over three-days in free-living subjects using the Intelligent Device for Energy Expenditure & Activity monitor (IDEEA, MiniSun, CA). The IDEEA is primarily a laboratory device for use under controlled conditions and over short measurement periods (<24 hours). This pilot study compared estimated EE from the IDEEA to that measured simultaneously using doubly-labelled water (DLW) in free-living subjects. Seven females and four males (mean age 38y, BMI 24.2kg·m-2) wore an IDEEA for 14 consecutive days during the waking hours. Apart from two, 24-hour periods when they were resident in a whole body calorimeter, subjects were free to undergo their normal activities. Compared to the DLW values, the IDEEA overestimated EE by 2MJ per day (9.5MJ ± 2.1MJ and 11.5MJ ± 2.3MJ respectively, p <0.001). The difference between the two EE values was associated negatively with subject's age (R2 = 0.408, p = 0.034), but there were no significant associations with subject's sex, height, weight or BMI. Replacing the IDEEA system's estimated values for resting metabolic rate, and the EE of sitting and standing, with measured values reduced the overestimate to 0.7MJ per day (p = 0.033). The IDEEA over-estimated EE compared to DLW, but the discrepancy can be reduced by using measured calibration values for sedentary activities instead of estimated ones. Acknowledgement DiOGenes is funded under the Sixth Framework Programme for Research and Technological Development of the European Union.