Hadith: The Messenger of Allah (may Allah's peace and blessings be upon him) used to spend consecutive nights with an empty stomach, and his household would find no supper, and their bread was mostly made of barley

عن عبدالله بن عباس رضي الله عنهما قال: كان رسول الله صلى الله عليه وسلم يبيت الليالي المتتابعة طَاوِياً، وأهلُهُ لا يجِدُون عَشَاءً، وكان أكثر خبزهم خبز الشعير.
[صحيح] - [رواه الترمذي وابن ماجه وأحمد]

‘Abdullāh ibn ‘Abbās (may Allah be pleased with him) reported: The Messenger of Allah (may Allah's peace and blessings be upon him) used to spend consecutive nights with an empty stomach, and his household would find no supper, and their bread was mostly made of of barley.
[Authentic hadith] - [Narrated by Ibn Majah - Narrated by At-Termedhy - Narrated by Ahmad]

Explanation

The Prophet (may Allah's peace and blessings be upon him) as well as his wives and dependents, used to go to sleep for several nights in a row without eating because they would not find any food for supper. Most of their bread was from barley, which was cheaper than wheat and other grains.