biostudies-literatureUnknown9Grundler FFasting provokes fundamental changes in the activation of metabolic and signaling pathways leading to longer and healthier lifespans in animal models. Although the involvement of different metabolites in fueling human fasting metabolism is well known, the contribution of tissues and organs to their supply remains partly unclear. Also, changes in organ volume and composition remain relatively unexplored. Thus, processes involved in remodeling tissues during fasting and food reintroduction need to be better understood. Therefore, this study will apply state-of-the-art techniques to investigate the effects of long-term fasting (LF) and food reintroduction in humans by a multi-systemic approach focusing on changes in body composition, organ and tissue volume, lipid transport and storage, sourcFrontiers in nutrition951000https://www.ebi.ac.uk/biostudies/studies/S-EPMC9713250biostudies-literatureLong-term fasting: Multi-system adaptations in humans (GENESIS) study-A single-arm interventional trial.PMC9713250Hofer SJCroisille PRuscica Mvon Schacky CMadeo FGrundler FMesnage RMitchell SJViallon MWilhelmi de Toledo FfalseLong-term fasting: Multi-system adaptations in humans (GENESIS) study-A single-arm interventional trial.Fasting provokes fundamental changes in the activation of metabolic and signaling pathways leading to longer and healthier lifespans in animal models. Although the involvement of different metabolites in fueling human fasting metabolism is well known, the contribution of tissues and organs to their supply remains partly unclear. Also, changes in organ volume and composition remain relatively unexplored. Thus, processes involved in remodeling tissues during fasting and food reintroduction need to be better understood. Therefore, this study will apply state-of-the-art techniques to investigate the effects of long-term fasting (LF) and food reintroduction in humans by a multi-systemic approach focusing on changes in body composition, organ and tissue volume, lipid transport and storage, sourc2022-01-01T00:00:00Z20222026-05-28T01:10:35.129Z2025-04-19T22:47:36.771ZS-EPMC97132503646642310.3389/fnut.2022.951000