This excerpt is taken from Sheikh Abu Hamza Abdul Khaliq Siddiqi's book Sahi Fazail-e-Amaal.
Allah Almighty says: ﴿وَإِذْ تَأَذَّنَ رَبُّكُمْ لَئِن شَكَرْتُمْ لَأَزِيدَنَّكُمْ ۖ وَلَئِن كَفَرْتُمْ إِنَّ عَذَابِي لَشَدِيدٌ﴾
"And when your Lord proclaimed: 'If you give thanks, I will surely increase you [in favor]; but if you deny, indeed, My punishment is severe.'"
Reference: (14-Ibrahim:7)
عن أنس بن مالك قال: قال رسول الله صلى الله عليه وسلم: إن الله ليرضى عن العبد أن يأكل الأكلة، فيحمده عليها، أو يشرب الشربة، فيحمده عليها
It is narrated from Sayyiduna Anas (RA) that the Messenger of Allah (SAW) said: "Indeed, Allah is pleased with the servant who, when he eats, praises Allah for it, or when he drinks, praises Allah for it."
Reference: Sahih Muslim, Book of Remembrance and Supplication, Chapter on the Recommendation of Praising Allah after Eating and Drinking, Hadith No: 2734.
Benefit:
It is thus understood that the person who says Alhamdulillah after eating is granted more by Allah Almighty. And He bestows His pleasure upon him. So, whoever attains the pleasure of the Lord, and the Lord becomes pleased with him, what greater blessing can there be than this? The people of Paradise will not be as happy and delighted by entering Paradise as they will be by receiving the pleasure of Allah. May Allah Almighty grant us His pleasure and satisfaction. Ameen!