Abstract Provided is an oil/fat composition comprising 60 to 100 wt. % of a diglyceride wherein the diglyceride has, as the fatty acid constituent thereof, 15 to 90 wt. % of an .omega. 3-unsaturated fatty acid having less than 20 carbon atoms and a cis .omega. 3-unsaturated fatty acid/(cis .omega. 6-unsaturated fatty acid+saturated fatty acid+trans unsaturated fatty acid) at a weight ratio of 1 to 6. The composition is excellent in visceral fat burning property, body fat burning property and stability against autoxidation.