Kansas City Star
Any restriction on something as basic and fundamental as eating for an entire community has, however, certain consequences for those who observe these laws. It transforms not only the eating, but the preparation of food into a sacred act that binds the individual and the community . Preparation of food, including the ritual slaughter of animals are all performed within a devotional context. In fact, Maimonides, when writing his 14-volume code of Jewish law, places the laws of forbidden foods within the volume that is called Kedusha (Sanctity).
These rules, like many others, became a foundation for a culture that transcends the boundaries of nations and holds together a people that had been in exile for 2,000 years, when our only homeland was the Torah.
In contemporary life these strictures are still relevant because sanctity never goes out of style and changing realities don't change one's relationship to the Creator. The dietary laws remind us of who we are and that sustenance is an opportunity for devotion.
In the Bible, we can find that of the “beasts of the earth,” you may eat those that have cloven hooves and chews a cud.
Of the things in the waters, you may eat anything that has fins and scales, but not shellfish. Someone might claim those are Old Testament, so don't apply to Christians.
But Matthew said in the New Testament: “Do not think I came to destroy the law or the prophets … till heaven and earth pass away, one jot or one tittle will by no means pass from the law.”
In Islam the Quran specifies a prohibition against eating swine and all pork byproducts, animals slaughtered in dedication to false gods, predatory creatures, animals that have been strangled, struck by an object or killed by a fall, or that are already dead.
Many view such restrictions, which also ban alcohol, as primitive and out-of-date, but following the holy books can have many benefits to the mind, the body, and the quality of life today.
There is no doubt that the body's arteries and heart appreciate a diet that cuts out bacon and ham. And notice, trichinosis, a parasite picked up from pigs, is far from eradicated.
Regardless of such benefits, the main reason that people of faith follow dietary restrictions of the holy books is simply because God said so.