title: Comparison of the GEM and the ECAL indirect calorimeters against the Deltatrac for measures of RMR and diet-induced thermogenesis.
abstract: The Deltatrac™ II Metabolic Monitor (Datex-Ohmeda Inc.) is considered the standard reference machine in indirect calorimetry; however, it is no longer commercially available thus there is a need for new machines. The gas exchange measurement (GEM; GEM Nutrition Ltd) and the ECAL (Health Professional Solutions) are alternative measuring systems. The aim of this study was to compare the ECAL and GEM with Deltatrac for measures of RMR and the GEM to the Deltatrac for measures of diet-induced thermogenesis (DIT). Twenty healthy participants were tested on test day 1 (T1) and test day 2 (T2). RMR was measured in a randomised order for 30 min on the Deltatrac, the GEM and the ECAL. Following this, a 1553 kJ meal was consumed and DIT was measured on the Deltatrac and the GEM in alternating 15 min intervals for 4 h. The GEM reported consistently higher values than the Deltatrac for VO2, VCO2, RMR and fat oxidation (P < 0·005). The ECAL was significantly higher than the Deltatrac for measures of VO2, RMR, carbohydrate oxidation (T2) and respiratory quotient and fat oxidation (T1, T2) (P < 0·05). There were no significant differences within repeated RMR measures on the ECAL, the GEM or the Deltatrac. DIT measures were consistently higher on the GEM (T1) (P < 0·005); however, there were no significant differences between repeated measures. The findings suggest that while the GEM and the ECAL were not accurate alternatives to the Deltatrac, they may be reliable for repeated measures.
authors.affiliation: Department of Sport and Health Sciences , Faculty of Health and Life Sciences , Oxford Brookes University , Functional Food Centre , Gipsy Lane , Oxford OX3 0BP , UK.
authors.forename: S
authors.initials: S
authors.lastname: Kennedy
authors.affiliation: Department of Nutrition and Dietetics , Faculty of Medicine , Nursing and Health Sciences , Monash University , 264 Ferntree Gully Road , VIC 3168 , Australia.
authors.forename: L
authors.initials: L
authors.lastname: Ryan
authors.affiliation: Department of Sport and Health Sciences , Faculty of Health and Life Sciences , Oxford Brookes University , Functional Food Centre , Gipsy Lane , Oxford OX3 0BP , UK.
authors.forename: A
authors.initials: A
authors.lastname: Fraser
authors.affiliation: Department of Sport and Health Sciences , Faculty of Health and Life Sciences , Oxford Brookes University , Functional Food Centre , Gipsy Lane , Oxford OX3 0BP , UK.
authors.forename: M E
authors.initials: ME
authors.lastname: Clegg
keywords: CHO, carbohydrate; DIT, diet-induced thermogenesis; Deltatrac; Diet-induced thermogenesis; ECAL; EE, energy expenditure; GEM; GEM, gas exchange measurement; MCT, medium-chain TAG; RMR; RQ, respiratory quotient; T1, test day 1; T2, test day 2