FKBP51-KO mice fed RD and HF diet exhibit altered substrate oxidation and elevated energy expenditure with reduced motor activity. Five-month-old WT and KO mice were subjected to indirect calorimetry to assess RERs, energy expenditure (heat), and motor activity. A, WT (n = 6) and KO (n = 6) mice on RD. B, WT (n = 7) and KO (n = 8) mice fed a HF diet for 4 weeks. Data shown are mean ± SEM; *, WT vs KO.