Mu'adh bin Anas (May Allah be pleased with him) reported

Messenger of Allah (ﷺ) said, "He who has taken food and says at the end: 'Al- hamdu lillahi-lladhi at'amani hadha, wa razaqanihi min ghairi haulin minni wa la quwwatin (All praise is due to Allah Who has given me food to eat and provided it without any endeavour on my part or any power),' all his past sins will be forgiven."

[Abu Dawud and At- Tirmidhi].