Disclosed is a ligand for peroxisome proliferator-activated receptor (PPAR) which originates in a safe food material. Specifically disclosed is a PPAR ligand which comprises, as the active ingredient, a Luffa acutangula L. extract or a novel compound contained in the Luffa acutangula L. extract. This PPAR ligand is efficacious in preventing and/or ameliorating obesity and obesity-related disorders such as insulin resistance, hyperlipemia, hypertension, diabetes, etc.