A person who recognizes after eating food (or drink) that he/she has eaten a haram meal, in case there was no likelihood of the food (drink) being harām and there were signs indicating that it was halal, for instance, he/she had received the food from a Muslim person or restaurant, like a person has not committed a sin and he/she is not counted to be sinful. However, if the food had been doubtful such as when he or she received this food from a non-Muslim individual (or at a restaurant…), in which position, it is his/her duty to conduct an investigation to make sure that the food or drink is halal. This is not permissible to eat food unless one is sure that it is halal. In case there isn’t any sign indicating that the food or drink is halal or not, the general principle applicable to meat is that it is considered as harām and impure. Hence, one who intends to eat it must make sure that it is halal.
Imam Sadeq (a.s.) says about the destructive impacts of sins:
"The effect of this sin is that it deprives [the sinner] of
worshipping. Sometimes, a man commits a sin at day time as a result of
which he becomes deprived of staying awake and offering Night Prayers
1 except for when he repents after his iniquity and reforms
1 - Javadi Amoli, Abdullah, Stages of Morality in the Quran, pg.153.
 - Al-Maedah: 39
On the whole, I recommend you to read the reference below completely to be more informed regarding the issue.