To provide a pharmaceutical product or food which has an excellent fat-accumulation-inhibiting activity and/or fat-metabolism-improving activity and which is effective for inhibition or improvement of obesity, fatty liver, etc. The present invention provides an agent for preventing or ameliorating obesity containing, as an active ingredient, cells of a lactic acid bacterium belonging to the genus Pediococcus, a cell culture thereof, or an extract of any of these.本發明提供一種醫藥品或食品，其係具有優異之脂肪堆積抑制及/或脂質代謝改善作用，對肥胖之抑制或改善、脂肪肝等有效。本發明之肥胖預防或改善劑係以屬於小球菌屬(Pediococcus)之乳酸菌之菌體或菌體培養物、或者該等之萃取物作為有效成分。
