Immunity-Based Evolutionary Interpretation of Diet-Induced Thermogenesis.
Diet-induced thermogenesis (DIT) has often been argued to be a physiological defense against obesity, but no empirical proof of its effectiveness in limiting human body weight gain is available. We here propose an immune explanation of DIT-i.e., that it results from the coevolution of host and gut microbiota (especially Firmicutes) that ferment ingested food and proliferate, causing periodic, vagally mediated increases in thermogenesis aimed at curtailing their expansion. Because of this evolutionary adaptive significance related to the immune system, DIT is not effective as an "adaptation" to maintain a certain body mass. Were DIT an effective adaptation to prevent obesity, the current obesity epidemic might not have occurred.
Physiology and Behavior Laboratory, Department of Health Sciences and Technology, ETH Zurich, 8603 Schwerzenbach, Switzerland; Institute of Anatomy, University of Zurich, 8057 Zurich, Switzerland. Electronic address: wan-hui-liao@ethz.ch.
Wan-Hui
WH
Liao
Institute of Evolutionary Medicine, Medical Faculty, University of Zurich, 8057 Zurich, Switzerland; Biological Anthropology and Comparative Anatomy Unit, University of Adelaide, Adelaide 5005, Australia.
Maciej
M
Henneberg
Physiology and Behavior Laboratory, Department of Health Sciences and Technology, ETH Zurich, 8603 Schwerzenbach, Switzerland. Electronic address: wolfgang-langhans@ethz.ch.
Wolfgang
W
Langhans
D000818:Animals; D005075:Biological Evolution; D004032:Diet; D004734:Energy Metabolism; D006801:Humans; D007109:Immunity; D008954:Models, Biological; D022722:Thermogenesis