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Updated: May 14, 2026
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Using a Combination of Indirect Calorimetry, Infrared Thermography, and Blood Glucose Levels to Measure Brown Adipose Tissue Thermogenesis in Humans
Published on: June 2, 2023
Adaptive thermogenesis with weight loss in humans
1Institut für Humanernährung und Lebensmittelkunde, Christian-Albrechts-Universität zu Kiel, Düsternbrooker Weg 17, 24105 Kiel, Germany. mmueller@nutrfoodsc.uni-kiel.de
Obesity (Silver Spring, Md.)
|February 14, 2013
Summary
Adaptive thermogenesis (AT) is a drop in energy expenditure during weight loss, independent of body changes. Its existence and clinical significance in humans remain debated due to inconsistent findings and varied research methods.
Area of Science:
- Human metabolism and energy balance
- Nutritional physiology
- Obesity research
Background:
- Adaptive thermogenesis (AT) describes a decrease in energy expenditure during weight loss, irrespective of body weight or composition.
- The existence and clinical significance of AT in humans have been inconsistently demonstrated, leading to ongoing debate.
Purpose of the Study:
- To clarify the definition and measurement of AT, addressing discrepancies in existing research.
- To investigate the development time course and quantify the magnitude of AT under controlled underfeeding conditions.
Main Methods:
- Controlled underfeeding protocols to assess energy expenditure changes.
- Analysis of hormonal and metabolic factors potentially influencing AT, including sympathetic nervous system activity, tri-iodothyronine (T3), and leptin.
- Differentiation of AT from diet-induced and cold-induced thermogenesis, examining organ contributions and mechanisms.
Main Results:
- AT development requires over two weeks of underfeeding.
- AT averages 0.5 MJ (120 kcal) but shows significant inter-individual variation.
- The resting and non-resting energy expenditure components of AT differ in their mechanisms and organ contributions.
Conclusions:
- AT characterization requires detailed analysis of energy expenditure components, body composition, and mathematical modeling.
- Further research is needed to establish the biological basis of AT and the influence of factors like age, sex, obesity, stress, and inflammation in humans.
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