Musannaf Ibn Abi Shayba 16:321

Abu Bakr narrated to us, he said: Abu Mu'awiyah narrated to us, from al-A'mash, from Abu Sufyan, from Jabir, who said: The Messenger of Allah (may Allah bless him and grant him peace) said: "The food of one is sufficient for two, and the food of two is sufficient for four."