This invention provides the use of a microorganism capable of improving both lipid metabolism and sugar metabolism. Specifically, the invention relates to: a lipid metabolism and/or sugar metabolism improver comprising, as an active ingredient, a bacterial cell selected from bacteria belonging to the genus Lactobacillus and the genus Bifidobacterium, a treated product of the bacterial cell, or a mixture thereof, having dual-agonistic activities to peroxisome proliferator activated receptor (PPAR)α and peroxisome proliferator activated receptor (PPAR)γ; to a food or a beverage comprising the improver; and to a pharmaceutical composition comprising the improver.