Immunity-Based Evolutionary Interpretation of Diet-Induced Thermogenesis

• Published in: Cell metabolism Vol. 23; no. 6; pp. 971 - 979
• Main Authors: Liao, Wan-Hui, Henneberg, Maciej, Langhans, Wolfgang
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 14.06.2016
• Subjects: Animals; Biological Evolution; Diet; Energy Metabolism; Firmicutes; Humans; Immunity; Models, Biological; Thermogenesis
• ISSN: 1550-4131; 1932-7420
• DOI: 10.1016/j.cmet.2016.05.002

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. •DIT has evolutionary significance in gut immunity and not energy homeostasis•Thermogenic Firmicutes bacteria outgrow other gut bacteria on cafeteria diets•Firmicutes-dominated microbiota compromise the intestinal epithelial barrier•DIT empowers immunity to curb diet-induced expansion of Firmicutes bacteria Liao et al. probe the physiological role of diet-induced thermogenesis (DIT) from an evolutionary point of view and suggest it results from coevolution of host and gut Firmicutes bacteria. DIT improves gut immunity and restricts the growth of Firmicutes bacteria, which boom on cafeteria diets to become potential health threats.