Affiliation:
1. Centres for Health Research, Princess Alexandra Hospital, The University of Queensland and The Translation Research Institute, Brisbane, Queensland, Australia
Abstract
Diet-induced thermogenesis (DIT) is energy dissipated as heat after a meal, contributing 5–15% to total daily energy expenditure (EE). There has been a long interest in the intriguing possibility that a defect in DIT predisposes to obesity. However, the evidence is conflicting; DIT is usually quantified by indirect calorimetry, which does not measure heat. Using gas exchange, indirect calorimetry measures total post-prandial EE, which comprises heat energy produced from brown adipose tissue (BAT) and energy required for processing and storing nutrients. We questioned whether DIT is reliably quantified by indirect calorimetry by employing infrared thermography to independently assess thermogenesis. Thermogenic activity of BAT was stimulated by cold and by a meal that induced a parallel increase in energy production. These stimulatory effects on BAT thermogenesis were inhibited by glucocorticoids. However, glucocorticoids enhanced postprandial EE in the face of reduced BAT thermogenesis and stimulated lipid synthesis. The increase in EE correlated significantly with the increase in lipogenesis. As energy cannot be destroyed (first law of thermodynamics), the energy that would have been dissipated as heat after a meal is channeled into storage. Post-prandial EE is the sum of heat energy that is lost (true DIT) and chemical energy that is stored. Indirect calorimetry does not reliably quantify DIT. When estimated by indirect calorimetry, assumed DIT can be a friend or foe of energy balance. That gas exchange-derived DIT reflects solely energy dissipation as heat is a false assumption likely to explain the conflicting results on the role of DIT in obesity.
Subject
Endocrinology,Endocrinology, Diabetes and Metabolism
Reference62 articles.
1. Glucocorticoids suppress brown adipose tissue function in humans: a double-blind placebo-controlled study;Diabetes, Obesity and Metabolism,2017
2. McCollum Award Lecture, 1995: diet, lifestyle, and weight maintenance;American Journal of Clinical Nutrition,1995
3. Infrared thermography in the detection of brown adipose tissue in humans;Physiological Reports,2014
4. Assumptions used in measurements of energy metabolism;Journal of Nutrition,1991
5. Thermal imaging to assess age-related changes of skin temperature within the supraclavicular region co-locating with brown adipose tissue in healthy children;Journal of Pediatrics,2012
Cited by
26 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献