God's laws for the Jєωs before Jesus dealt with a lot of things to do with purity.
Off the top of my head there are the laws of, no sex when one's wife is on period, not eating certain foods because of uncleanliness (impure), not using 2 fabrics in one clothing item, etc.
These cultural laws God gave the Jєωs a lot of time dealt with purity- but these laws were fulfilled (although it looks like they were abolished) by Jesus- One of the reasons why (according to my understanding) is that these are pure on a material level, not a spiritual one.
There are benefits and negatives to pretty much any food, pigs are dirty and unclean-but that is why we cook meat, we wash away the toxins or diseases.