Fasting substrate oxidation at rest assessed by indirect calorimetry: is prior dietary macronutrient level and composition a confounder?
- Miles-Chan, Jennifer L. Division of Physiology, Department of Medicine, University of Fribourg, Switzerland
- Dulloo, Abdul G. Division of Physiology, Department of Medicine, University of Fribourg, Switzerland
- Schutz, Yves Division of Physiology, Department of Medicine, University of Fribourg, Switzerland
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14.04.2015
Published in:
- International Journal of Obesity. - 2015, vol. 39, no. 7, p. 1114-1117
English
Indirect calorimetry, the measurement of O₂ consumption and CO₂ production, constitutes an invaluable tool as the most common method for analyzing whole-body energy expenditure, and also provides an index of the nature of macronutrient substrate oxidation—namely, carbohydrate (CHO) versus fat oxidation. The latter constitutes a key etiological factor in obesity as this condition can only develop when total fat oxidation is chronically lower than total exogenous fat intake. The standardization of indirect calorimetry measurements is essential for accurately tracking the relative proportion of energy expenditure derived from CHO and fat oxidation. Here we analyze literature data to show that the average fasting respiratory quotient typically shifts from approximately 0.80 to 0.90 (indicating a doubling of resting CHO oxidation) in response to a switch in dietary CHO intake (as % energy) from 30 to 60%. This underscores the importance of taking into account dietary macronutrient composition prior to indirect calorimetry studies in the interpretation of data on substrate utilization and oxidation.
- Faculty
- Faculté des sciences et de médecine
- Department
- Département de Médecine
- Language
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- English
- Classification
- Biological sciences
- License
- License undefined
- Identifiers
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- RERO DOC 255880
- DOI 10.1038/ijo.2015.29
- Persistent URL
- https://folia.unifr.ch/unifr/documents/304440
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