A fat-reducing agent includes a carotenoid-containing composition as an active ingredient, the carotenoid-containing composition including: a carotenoid component including at least one crystalline carotenoid, wherein at least 90% by mass of the crystalline carotenoid is in the non-crystalline state; and a (poly)glycerin fatty acid ester containing from 1 to 6 glycerin units and from 1 to 6 fatty acid units, and having at least one hydroxyl group in the glycerin units.