It is intended to provide a peroxisome proliferator-activated receptor (PPAR) activator, which is free from the problem of side effects, can be taken over a long term and has no characteristics taste. .beta.-cryptoxantine is employed as a PPAR activator. .beta.-cryptoxantine, which is contained in a large amount in the pulp of citrus fruits (in particular, mandarin-type citrus fruits) such as satsuma oranges, for example, has been consumed for many years. Thus, it is free from any problem in safety and has a low calorie content. Therefore, it can be taken over a long term. Because of being tasteless and odorless, moreover, .beta.-cryptoxantine would not damage the unique taste when added to a food. Therefore, it can be added to foods and taken.