A method for screening a substance for treating visceral adiposity syndrome comprises: (1) extracting a total RNA fraction from skeletal muscle collected from non-human mammals of a group to which a predetermined amount of the test substance has been administered and from non-human mammals of a group to which the test substance has not been administered; (2) quantifying the expression quantity of mRNA in the total RNA fraction extracted that encodes a glucose transporter gene by a specific method; and (3) comparing and analyzing the quantity of the test substance ingested, the body weight gain, and the expression quantity of RNA encoding the glucose transporter gene during the administration period for the non-human mammals of the test substance-administered group to these quantities for the non-human mammals that constitute the test substance-unadministered group to thereby determine the effect of the test substance on the metabolic syndrome.