The Messenger of Allah ﷺ said, "Food enough for one is enough for two, and food enough for two is enough for four."
حدثنا عفان قال حدثنا حماد بن سلمة عن علي بن زيد عمن
أن رسول الله ﷺ قال طعام الواحد يكفي الاثنين وطعام الاثنين يكفي الأربعة
Its isnad is daif, as it contains a narrator who is not named, but the hadith is sahih. Muslim reported it (3/1630, no. 2059) in the chapter on food and drink, on the virtue of sharing food, as did Tirmidhi (4/267, no. 1820) in the chapter on foods, on what has been said about the food of one person, Ibn Majah (2/1084, no. 3254) with similar wording, Darimi (2/136, no. 2044), and Abdul-Razzaq (10/418, no. 19557).