Musnad Ahmad 32:228

Abu Usamah narrated to us, Zakariya ibn Abi Za'idah informed us, from Sa'id ibn Abi Burdah, from Anas ibn Malik, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "Indeed, Allah is pleased with the servant who eats a morsel of food or drinks a drink, and then praises Allah for it."