lbn 'Abbaas Radiyallahu 'Anhu reports that:
"Rasulullah Sallallahu 'Alayhi Wasallam and his family spent many consecutive nights without food, because there would be no supper. The bread of Rasulullah Sallallahu 'Alayhi Wasallam was mostly made of barley". (Sometimes bread made of wheat was also available). (DE)
English reference (DE): Book 24, Hadith 137 (DE)
Arabic reference (DE): Book 25, Hadith 145 (DE)