The present invention provides a method of reducing body fat, comprising administering a composition comprising an effective amount of Lactobacillus paracasei or a metabolite thereof to a subject in need thereof. The Lactobacillus paracasei or the metabolite thereof can effectively convert the fatty acid into conjugated linoleic acid, inhibit the accumulation of fat and promote the decomposition of fat in fat cells, and can effectively reduce the percentage of body fat, waist circumference, and hip circumference, and simultaneously increase the muscle mass of the subject.
