the Prophet (may Allah's peace and blessings be upon him) said: ''Whoever eats food and says: 'Praise be to Allah who fed me and provided me with this food through no might or power on my part', his past sins will be forgiven. [Ibn Maajah]

مَنْ أَكَلَ طَعَامًا، فقال: الحمدُ للهِ الذي أَطْعَمَنِي هَذَا، وَرَزَقْنِيهِ مِنْ غَيرِ حَوْلٍ مِنِّي وَلَا قُوَّةٍ، غُفِرَ له ما تَقَدَّمَ مِنْ ذَنْبِهِ». حسن.] - [رواه أبو داود والترمذي وابن ماجه وأحمد.]