Sayyiduna Abu Barzah al-Aslami (may Allah be pleased with him) said: The Arabs used to say: "Whoever eats bread will become fat." When we conquered Khaybar, we drove them away from their bread. I sat down on it and ate from it until I was full. Then I kept looking at my body (to see) whether I had become fat.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب السير / 17998