It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that the Prophet (peace and blessings be upon him) did not fast in the plain of Arafah; Sayyidah Umm al-Fadl (may Allah be pleased with her) sent him milk, which he drank.
Hadith Referenceمسند احمد / ومن مسند بني هاشم / 2517