Comparison of energy assessment methods in overweight individuals.

Practical methods of assessing resting energy expenditure (REE) could be useful in large populations of overweight and obese individuals during phases of weight loss and weight-loss maintenance to address weight regain. We compared predicted and measured REE using the MedGem handheld device and a traditional, indirect calorimeter in middle-aged men and women who were overweight and obese (body mass index ≥ 25.0 and <40.0). Each subject (n=88) completed traditional, indirect calorimetry and handheld calorimetry in random order. A subset of participants (n=10) completed each of these assessments at three different time points to examine their test-retest reliability. We found that MedGem estimates of REE were significantly greater than estimates with the traditional, indirect calorimeter and the predicted REE using the Harris-Benedict equation (P<0.01). Intra-class correlations were .70 (P=0.15) for repeated recordings with the MedGem and .84 (P=0.65) for traditional indirect calorimetry. The MedGem can overestimate REE in middle-aged overweight/obese individuals and has moderate test-retest reliability. Indirect calorimetry is the preferred measurement of REE in this population.