Authentic Supplication Number 207.

The Messenger of Allah  said: Whoever would eat some food, and then say: 'Al-hamdu lil-lahi 'al-lathee 'at`amanee hatha, wa razaqaneehi min ghayri hawlin minnee wa la quwwatin (223), his previous sins would be forgiven.

Footnotes.
(223) All praise be to Allah Who has fed me this, and provided me with it with neither ability on my part nor strength.

Reporters.
Reported by At-Tirmidhi who said it was comely. Al-Albani said that he agreed with At-Tirmidhi, that so did Al-Hafith Ibn Hajar, and that Abu Dawood and Ibn Majah also reported it. Al-Albani included this hadeeth in The Authentic of Good Sayings as #148.