AimTo investigate the role of the acyl-coenzyme A∶cholesterol acyltransferase-2 (ACAT-2) 734 C/T polymorphism on ratios of serum lipids and its interactions on the ratios with a high-carbohydrate/low-fat (HC/LF) diet in a young healthy Chinese population.MethodsAfter a washout diet for seven days, fifty six young healthy subjects were given the HC/LF diet for six days.The serum lipid profiles were analyzed using the twelve-hour fasting venous blood samples collected in the mornings of the first, the eighth and the fourteenth days.The ratios of TG/HDLC, log (TG/HDLC), TC/HDLC and LDLC/HDLC were calculated.The ACAT-2 734 C/T polymorphism was analyzed by restriction fragments patterns after amplified by polymerase chain reactions.ResultsAt baseline, the female carriers of the T allele had significantly lower log (TG/HDLC) than the female subjects with the CC genotype.The male subjects