The pork issue has been coming up a lot in my life, too.
I've read that pigs do not have a built in toxic dispenser like other animals (cows have four stomachs, etc.) and they are basically garbage disposals and build up waste in their systems.
When Jesus told the story about the prodigal son, I think it was basically to signify how very LOW he had fallen (living and eating with pigs, the most unclean animal in the bible) for his shortsightedness and dishonor of his father and inheritance. And also to show that no matter how far we stray from our heavenly Father, that He will gladly welcome us back when we're ready to repent.
Shellfish are likewise garbage disposals or "bottom-dwellers": if you watch catfish, shrimp, lobster, oysters, etc., in a fish tank, you'll notice they're cleaning the bottom of the tank (eating the leftovers and poop of the other fish). IMHO, they really can't have too many beneficial nutrients in their systems.
We don't bring any of these kinds of foods into our house. My take is that if God forbade them to his chosen people, there must be some good in avoiding them.
That said, we do have an occasional pizza or piece of shrimp when we're eating out. But since i have been avoiding pork, I ALWAYS get bad gas when I do eat it!!
The clean versus unclean foods that people are talking about on 3FC are mostly processed, added sugar, added this or that, versus they way God put food on the planet to be eaten. The healthiest way to eat something is when you can easily figure out how it got from the vine/tree to your mouth. Eating a whole, fresh tomato is better than eating tomato sauce, and eating tomato sauce is better than eating ketchup. The closer it looks to the way it did at the beginning, the healthier (i.e. "cleaner") it is. The less added sugar, fat, etc, there is, the better. Hope this helps!
