Chronic alcohol consumption contributes to fatty liver disease. My studies revealed that hepatic circadian clock is disturbed in the alcohol-induced hepatic steatosis, and effects of chronic alcohol administration upon the clock itself may contribute to steatosis. My studies also found that chronic alcohol consumption and liquid diet can differentially modulate the daily rhythmicity of locomotor and feeding behaviors; aspects that might contribute to disturbances in the circadian timing system and development of hepatic steatosis. Inhibitor of DNA binding 2 (ID2) is a helix-loop-helix transcriptional repressor. My studies have demonstrated that Id2 null mice have sex-specific enhancement of insulin sensitivity and elevated glucose uptake in skeletal muscle and brown adipose tissue. Furthermore, I extend my studies on the characterization of the Id2 null mouse metabolic phenotype under energy-rich diet challenge in sex-specific context. These data provides insights into the impact of Id2 deficiency on metabolic homeostasis of mice in sexspecific manner.