Zadhan narrates from Sayyiduna Salman (may Allah be pleased with him) that it was in the Torah that there is blessing in performing wudu before eating. I mentioned this before the Prophet (peace and blessings be upon him), and he (peace and blessings be upon him) said: "Performing wudu before and after eating is a blessing."
Qays bin al-Rabi' is not a strong narrator, so washing the hands before eating is not established by any hadith.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصداق / 14604