The present invention provides a fat accumulation inhibitor, an anti-fat precursor differentiation agent, an agent for reducing visceral fat, and a food or beverage for reducing visceral fat, comprising as an active ingredient a chicken egg containing 4.2 mass ppm or more of iodine. The present invention also provides a visceral fat reducing agent which is used as an active ingredient which is an egg yolk extract of avian eggs containing an iodinated peptide and which is administered as an amount of iodine of 300 μg or more per day.４．２質量ｐｐｍ以上のヨウ素を含有する鳥卵を有効成分とする、脂肪蓄積抑制剤、脂肪前駆細胞の分化抑制剤、内臓脂肪低減剤、及び内臓脂肪低減用飲食品を提供する。また、ヨウ化ペプチドを含有する鳥卵の卵黄抽出物を有効成分とし、１日当たりのヨウ素量として３００μｇ以上投与されるように用いられる内臓脂肪低減剤を提供する。
