The present invention provides a pharmaceutical composition and a food composition containing tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) as an active ingredient for prevention or treatment of metabolic diseases. The TRAIL according to the present invention can reduce blood glucose, neutral fat, cholesterol, and free fatty acid, and neutral fat in liver, and reduce the synthesis of fat, and promote the lipid metabolism, and thus can be effectively used for the prevention or treatment of metabolic diseases.
