Abstract: Objective To investigate the effect of resveratrol(RSV)and caloric restriction(CR)on hepatic steatosis in obese rats fed with high fat/sugar diet.Methods Forty Sprague-Dawley(SD)rats were randomly divided into a model and a control group and fed with high-fat/sugar and basic diet for 8 weeks.The obese rats with the average weight of 1.96 times standard deviation of the control group were picked out from the model group at the end of 8th week and then were randomly divided into obese,RSV(250 mg/kg)and CR(60%/d)groups.The improvements of hepatic steatosis of the rats were observed at the end of 20th week.Results At the end of 20th week,the mean body weight of rats in obese,RSV CR and control groups were 759.30±16.75,689.30±8.55,586.10±11.35,and 598.00±9.8 g,respectively,and the mean body weight of the obese group was higher than that of the control group(P<0.01)and that of RSV and CR group were lower than that of the obese group(P<0.05).Total energy intake in obese group was the highest,and that of the CR group was the lowest.The liver silent information regulator 1(Sirt1),peroxisome proliferator-activated receptor-coactivator 1α(PGC-1α)mRNA expression in obese,RSV,and CR groups were 0.42±0.04,0.79±0.16,0.88±0.06,and 0.67±0.19,1.26±0.34,2.35±0.37,respectively,and those in RSV and CR groups were higher than those of the obese group(P<0.01).The vacuolar accumulation was observed in liver cell of obese rats rats,and the rats in RSV and CR groups had relatively mild hepatic steatosis.Conclusion Resveratrol can simulate the energy restriction to reduce hepatic steatosis,and the mechanism may be related to the increased Sirt1 and PGC-1α mRNA expression and fatty acid β-oxidation function.