To prepare a medicine capable of reducing body fat storage and mitigating insulin resistance, hyperinsulinism, hyperglycemia and type II diabetes by resetting the daily rhythm of prolactin in a human, etc., at that of a thin and healthy human, etc.

This medicine comprises a prolactin-inhibiting compound such as bromocriptine and is capable of resetting the daily rhythm of prolactin in an animal or a human at that of a thin and healthy animal or human. Furthermore, the dose of the prolactin-inhibiting compound such as a dopamine antagonistic agent is preferably within the range of 3-20μg based on one pound (454g) body weight when treating the human.