Whole-Room Indirect Calorimetry in the Study of Obesity, Insulin Resistance and Metabolic Flexibility: A Narrative Review
- 1Second Department of General and Gastroenterological Surgery, Medical University of Bialystok, 15-089 Bialystok, Poland
- 2Doctoral School, Medical University of Bialystok, 15-089 Bialystok, Poland
Abstract
Obesity and insulin resistance are characterized by substantial heterogeneity in energy expenditure and substrate utilization. Whole-room indirect calorimetry (WRIC) enables continuous assessment of oxygen consumption, carbon dioxide production, energy expenditure, respiratory exchange ratio (RER), and substrate oxidation under controlled conditions. This narrative review examines the physiological interpretation, methodological strengths, limitations, and applications of WRIC in obesity, insulin resistance, metabolic flexibility, and weight-loss interventions. By enabling prolonged observation during resting, postprandial, exercise, and sleep periods, WRIC complements short-term indirect calorimetry and free-living energy expenditure measurements obtained using doubly labeled water. Validation studies generally demonstrate high technical accuracy and reproducibility for respiratory gas exchange and 24 h energy expenditure measured using WRIC. In contrast, estimates of the thermic effect of food, short-term changes in RER, and substrate oxidation are more sensitive to protocol design, energy balance, physical activity, and analytical procedures. Available studies demonstrate substantial interindividual variability rather than a uniform metabolic pattern associated with obesity or insulin resistance. Direct WRIC evidence concerning contemporary anti-obesity pharmacotherapy and metabolic and bariatric surgery remains limited. Standardized protocols and complementary assessments of body composition, insulin sensitivity, and free-living energy expenditure are needed to improve the comparability and interpretation of findings across studies.
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BibTeX
@article{zahorodnii2026wholeroom,
title = {{Whole-Room Indirect Calorimetry in the Study of Obesity, Insulin Resistance and Metabolic Flexibility: A Narrative Review}},
author = {Andrii Zahorodnii and Alicja Jelska and Paulina Głuszyńska and Layth Majeed Mhayyal Almltashe and Hady Razak Hady},
journal = {Nutrients},
year = {2026},
month = oct,
doi = {10.3390/nu18193287},
url = {https://europepmc.org/article/PMC/PMC13667147},
note = {CC BY},
}
RIS
TY - JOUR
TI - Whole-Room Indirect Calorimetry in the Study of Obesity, Insulin Resistance and Metabolic Flexibility: A Narrative Review
AU - Andrii Zahorodnii
AU - Alicja Jelska
AU - Paulina Głuszyńska
AU - Layth Majeed Mhayyal Almltashe
AU - Hady Razak Hady
PY - 2026
DA - 2026/10/01
JO - Nutrients
DO - 10.3390/nu18193287
UR - https://europepmc.org/article/PMC/PMC13667147
AB - Obesity and insulin resistance are characterized by substantial heterogeneity in energy expenditure and substrate utilization. Whole-room indirect calorimetry (WRIC) enables continuous assessment of oxygen consumption, carbon dioxide production, energy expenditure, respiratory exchange ratio (RER), and substrate oxidation under controlled conditions. This narrative review examines the physiological interpretation, methodological strengths, limitations, and applications of WRIC in obesity, insulin resistance, metabolic flexibility, and weight-loss interventions. By enabling prolonged observation during resting, postprandial, exercise, and sleep periods, WRIC complements short-term indirect calorimetry and free-living energy expenditure measurements obtained using doubly labeled water. Validation studies generally demonstrate high technical accuracy and reproducibility for respiratory gas exchange and 24 h energy expenditure measured using WRIC. In contrast, estimates of the thermic effect of food, short-term changes in RER, and substrate oxidation are more sensitive to protocol design, energy balance, physical activity, and analytical procedures. Available studies demonstrate substantial interindividual variability rather than a uniform metabolic pattern associated with obesity or insulin resistance. Direct WRIC evidence concerning contemporary anti-obesity pharmacotherapy and metabolic and bariatric surgery remains limited. Standardized protocols and complementary assessments of body composition, insulin sensitivity, and free-living energy expenditure are needed to improve the comparability and interpretation of findings across studies.
SN - 2072-6643
ER -