Ba'al Shem Tov, Kuntres Meirat Einayim 10/בעל שם טוב על התורה·קונטרס מאירת עינים י׳

1I heard that when Rabbi Dov Ber saw the Baal Shem Tov eat, it seemed that he ate like an angel, and not a human being. And once, he saw that he wasn’t eating like an angel, because he saw him eat like a human being.Ohr HaChochma, Beshalach