The Prophet says that one of the major causes of the unaccepted supplication of the believer is that he eats foods that are unlawful.
عَنْ أَبِي هُرَيْرَةَ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ” أَيُّهَا النَّاسُ إِنَّ اللَّهَ طَيِّبٌ لاَ يَقْبَلُ إِلاَّ طَيِّبًا وَإِنَّ اللَّهَ أَمَرَ الْمُؤْمِنِينَ بِمَا أَمَرَ بِهِ الْمُرْسَلِينَ فَقَالَ { يَا أَيُّهَا الرُّسُلُ كُلُوا مِنَ الطَّيِّبَاتِ وَاعْمَلُوا صَالِحًا إِنِّي بِمَا تَعْمَلُونَ عَلِيمٌ} وَقَالَ { يَا أَيُّهَا الَّذِينَ آمَنُوا كُلُوا مِنْ طَيِّبَاتِ مَا رَزَقْنَاكُمْ} ” . ثُمَّ ذَكَرَ الرَّجُلَ يُطِيلُ السَّفَرَ أَشْعَثَ أَغْبَرَ يَمُدُّ يَدَيْهِ إِلَى السَّمَاءِ يَا رَبِّ يَا رَبِّ وَمَطْعَمُهُ حَرَامٌ وَمَشْرَبُهُ حَرَامٌ وَمَلْبَسُهُ حَرَامٌ وَغُذِيَ بِالْحَرَامِ فَأَنَّى يُسْتَجَابُ لِذَلِكَ.[1]
Abu Huraira reported Allah’s Messenger (may peace be upon him) as saying: O people, Allah is Good and He therefore accepts only that which is good. And Allah commanded the believers as He commanded the Messengers by saying, “O Messengers, eat of the good things, and do good deeds; verily I am aware of what you do”. And He said: ‘ Oh those who believe, eat of the good things that We gave you” He then made a mention of a person who travels widely, his hair disheveled and covered with dust. He lifts his hand towards the sky (and thus makes the supplication):” O Lord Lord,” whereas his diet is unlawful, his drink is unlawful, and his clothes are unlawful. He is nourished by unlawful. How can then his supplication be accepted?
Eating on a full stomach is the reason for so many impending threats to the body and soul. It is a threat to the body because it causes obesity and all related ills. It makes the man lazy and idle, thus preventing him from performing productive and fruitful activities. The authors pointed out five important risks one triggers by eating a full stomach.
Ibn al-Haaj said: Eating in and of itself falls into various categories: obligatory, recommended, permissible, disliked and forbidden.
That which is obligatory is that which will keep him going so that he can fulfil his obligatory duties towards his Lord, because that which is essential to doing something obligatory is also obligatory.
That which is recommended is that which will help him to do Naafil acts of worship, acquire knowledge and do other acts of obedience.
That which is permissible is that which enables one to fill one’s stomach in the manner prescribed in Shareea.
That which is disliked is that which is a little more than is enough to fill the stomach but does not harm one.
That which is forbidden is eating a great deal that is harmful to the body.
He taught his Ummah about protecting people from diseases caused by eating and drinking. He said:
مَا مَلأَ آدَمِيٌّ وِعَاءً شَرًّا مِنْ بَطْنٍ حَسْبُ الآدَمِيِّ لُقَيْمَاتٌ يُقِمْنَ صُلْبَهُ فَإِنْ غَلَبَتِ الآدَمِيَّ نَفْسُهُ فَثُلُثٌ لِلطَّعَامِ وَثُلُثٌ لِلشَّرَابِ وَثُلُثٌ لِلنَّفَسِ [2]
‘A human being fills no worse vessel than his stomach. It is sufficient for a human being to eat a few mouthfuls to keep his spine straight. But if he must (fill it), then one third of food, one third for drink and one third for air.’”