Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) says: It is the Sunnah that you eat something before going out (for the Eid prayer), even if it is only one date.
Al-Bazzar recorded it, and al-Tabarani in al-Mu'jam al-Awsat and al-Mu'jam al-Kabir. His wording is: "It is the Sunnah that on the day of Eid al-Fitr you do not go out until you have given sadaqat al-fitr and eaten something before going out." The chain of al-Tabarani is hasan (good), and the chain of al-Bazzar contains a narrator whom I do not know.