The present invention relates to a method for preventing or treating obesity, diabetes, dyslipidemia, fatty liver or insulin resistance syndrome, comprising: administering to a mammalian subject in need thereof a therapeutically effective amount of a composition comprising adipic acid. The present composition containing adipic acid as an active ingredient is very effective in preventing or treating obesity, diabetes, dyslipidemia, fatty liver (preferably, non-alcoholic fatty liver) or insulin resistance syndrome. The composition of the present invention useful as pharmaceuticals compositions or functional food compositions has therapeutic efficacies for obesity, dyslipidemia or fatty liver, and also induces significant decrease in fasting glucose level and blood insulin level to improve type 2 diabetes, insulin resistance and related metabolic diseases.
