Longevity & AgingFasting for Longevity: What the Science Actually Supports
This comprehensive 2025 review in Endocrine Reviews examines the biology of fasting across three dimensions: the adaptive physiological response to starvation, potential longevity mechanisms, and the clinical evidence from human trials. The authors cover glycogenolysis, gluconeogenesis, lipid mobilization, ketogenesis, and hormonal adaptations including leptin-driven reductions in energy expenditure. They analyze caloric restriction data from model organisms showing consistent lifespan extension, then critically evaluate human randomized controlled trials of intermittent fasting and time-restricted eating. While cardiometabolic signals of benefit emerge, the review flags bone fragility as a serious and underappreciated risk of fasting-associated weight loss, cautioning that benefits may not be independent of weight loss itself.
