The present invention provides metabolic improvers containing rare fatty acids such as hydroxylated fatty acids and oxo fatty acids, and foods, pharmaceuticals and the like containing the metabolic improvers.本発明は、水酸化脂肪酸、オキソ脂肪酸等の希少脂肪酸を含む代謝改善剤、さらに、当該代謝改善剤を含む食品、医薬品等を提供する。