The PPARα agonists (Wy-14643 and GW7647) and endogenous PPARα agonists (oleoylethanolamide) treatment reduced the body weight gain and improved the hyperlipidemia via appetite-suppressing effect (within a day) in an obese animal model wherein the hyperlipidemia was mainly due to the high food intake [18–21]. The gene discussed is PPARA; the disease is hyperlipidemia.