The findings of this study highlight the novel role(s) for skeletal muscle Bmal1 in regulating tissue glucose metabolism (i.e., decreased GLUT4 and glycolytic enzymes), substrate utilization (i.e., changes in citrate to isocitrate within the TCA cycle), as well as system homeostasis (i.e., hyperglycemia in the non-fasting condition, glucose intolerance, and altered body composition). The gene discussed is HK1; the disease is Glucose intolerance.