Yo-Yo Dieting

This episode challenges the common belief that weight gain in middle age is caused by a slowing metabolism, asserting that adult metabolism generally remains stable until after age sixty. Instead, it explains that weight gain is primarily driven by lifestyle factors, such as reduced physical activity and increased caloric intake. It details how the body mounts a powerful biological defense against weight loss, interpreting caloric restriction as a threat and triggering adaptive thermogenesis, which suppresses metabolism and increases hunger. Consequently, repeated cycles of weight loss and regain, known as weight cycling, become progressively more difficult and may disrupt metabolic health. The episode concludes that the most effective strategy for lifelong weight management is preventing weight gain through consistent lifestyle adjustments rather than relying on restrictive dieting after weight has accumulated.Sources:Herman Pontzer, Yosuke Yamada, Hiroyuki Sagayama, Philip N. Ainslie, Lene F. Andersen, Liam J. Anderson, Lenore Arab, Issaad Baddou, Kweku Bedu-Addo, Ellen E. Blaak, Stephane Blanc, Alberto G. Bonomi, Carlijn V.C. Bouten, Pascal Bovet, Maciej S. Buchowski, Nancy F. Butte, Stefan G. Camps, Graeme L. Close, Jamie A. Cooper, Richard Cooper, et al. Daily energy expenditure through the human life course. Science, 373(6556):808–812, 2021. doi:10.1126/science. abe5017.Allyson K. Palmer and Michael D. Jensen. Metabolic changes in aging humans: current evidence and therapeutic strategies. The Journal of Clinical Investigation, 132(16):e158451, 2022. doi:10.1172/JCI158451.Xiaotao Shen, Chuchu Wang, Xin Zhou, Wenyu Zhou, Daniel Hornburg, Si Wu, and Michael P. Snyder. Nonlinear dynamics of multi-omics profiles during human aging. Nature Aging, 4:1619–1634, 2024. doi:10.1038/s43587-024-00692-2.Paul S. MacLean, Audrey Bergouignan, Marc-Andre Cornier, and Matthew R. Jackman. Biology’s response to dieting: the impetus for weight regain. Amer- ican Journal of Physiology-Regulatory, Integrative and Comparative Physiology, 301(3):R581–R600, September 2011. doi:10.1152/ajpregu.00755.2010.