Impact of fasting on the AMPK and PGC-1α axis in rodent and human skeletal muscle: A systematic review

Based primarily on evidence from rodent models fasting is currently believed to improve metabolic health via activation of the AMPK-PGC-1 alpha axis in skeletal muscle. However, it is unclear whether the skeletal muscle AMPKPGC-1 alpha axis is activated by fasting in humans. The current systematic review examined the fasting response in skeletal muscle from 34 selected studies (7 human, 21 mouse, and 6 rat). From these studies, we gathered 38 unique data points related to AMPK and 47 related to PGC-1 alpha. In human studies, fasting mediated activation of the AMPK-PGC-1 alpha axis is largely absent. Although evidence does support fasting-induced activation of the AMPK-PGC-1 alpha axis in rodent skeletal muscle, the evidence is less robust than anticipated. Our findings question the ability of fasting to activate the AMPK-PGC-1 alpha axis in human skeletal muscle and suggest that the metabolic benefits of fasting in humans are associated with caloric restriction rather than the induction of mitochondrial biogenesis.