It is narrated from Sayyiduna Abu Umamah al-Bahili (may Allah be pleased with him); he said that whenever the Messenger of Allah (peace and blessings be upon him) ate food, he would say: "Al-hamdu lillahi hamdan kathiran tayyiban mubarakan fihi, ghayra makfurin wa la muwadda'in wa la mustaghnan 'anhu (All praise is for Allah, abundant, pure and blessed praise, which is not to be met with ingratitude, nor abandoned, nor can one ever be free of need of it)."
Hadith Referenceالمعجم الكبير للطبراني / باب الصاد / 7604