How could you? The idea of God by itself is just a weird metaphysical claim like "maybe we're all actually in the Matrix"--okay, I fully admit that possibility, but there's nothing I can do about it, by itself.

Which is why theistic religions don't stop with God. They say things like, "God exists, and he says don't eat pork. Seriously. DON'T EAT PORK." That's actionable.

To be fair about the Biblical food and health mentions, it was more a health guide for the ancient world than anything else. Deuteronomy 23:9-14 are about cleanliness and Leviticus 11 covers the food.

Yes, but the whole God thing is just to motivate people not to eat pork. Apparently, people are more willing to do what they're told if you claim the instructions are of supernatural origin.

I find it strange to separate philosophy from practicality. If your philosophy does not have practical implications, you're doing it wrong.

I'm also not a pagan nor a Christian, but I celebrate their Christmas holiday.

But that would be for either traditional or cultural reasons, not philosophical reasons.