UCP1 and Atrophy: This revealed a gradual and significant decrease in Ucp1 levels along the advancement of aging (Figure S1A, Supporting Information), which is in consistent with previous study showing that aging leads to a programmed loss of thermogenic gene expression in murine iWAT.[11] In comparison, the enhancements in muscular atrophic gene MuRF‐1 expression in skeletal muscle only become apparent in late stage of life (Figure S1B, Supporting Information), suggesting that thermogenic fat function decline preceded muscle atrophy during aging.