Musnad Abu Ya'la al-Mawsili 148:103

Muhammad ibn Bahr narrated to us, Muhammad ibn Ya'la narrated to us, 'Anbasah ibn 'Abd al-Rahman narrated to us, from Ibn 'Alaq, from Anas ibn Malik, who said: The Messenger of Allah (may Allah bless him and grant him peace) said: "Eat dinner, even if it is with a handful of dried dates, for leaving dinner is a cause of aging."