I'm not familiar with Body By God, but it sounds as though it may be similar to The Maker's Diet? I haven't read that yet either, but my friend that gave me the kick start to eating real food was quite enamored with it for awhile.
I consider myself a WAPFer, though I mostly eat in line with Primal (lacto-paleo). I don't consider grains to be inherently evil- but most of us have become so damaged over the years that grains certainly do us no favors. We no longer properly prepare grains to reduce their anti-nutrients, we blast them with nasty pesticides and herbicides and many are gmo, and our modern wheat is not what they ate in Biblical times (they ate Emmer wheat- aka Farro- and Einkorn, which have a different sort of gluten and much lower amount, spelt is actually after the Bible, though not long after). I never liked legumes except for peanuts, and avoiding sugar isn't hard if you're not eating baked goods. :-)
As for problems when discussing Paleo with your religious friends, I recommend sticking to the science of it, rather than the evolutionary principle. When my mother brought up the argument of grains being eaten in the Bible, I said something along the lines of "Wine is in the Bible too, but you wouldn't tell a recovering alcoholic that they can have wine because it's Biblical, would you? There are some things that are fine for healthy people, but I'm not healthy."
If you know why you eat the way you do, stick to those reasons. The name is just a convenient way to sum up how you eat. "I'm Paleo", "I'm vegetarian", "I'm meatatarian", "I'm a Real Foodie". If you aren't sure why you're eating paleo, then I recommend doing a little experimenting to find out what your body responds best to. Cut out one element for 2 weeks to a month, no cheating at all, then re-introduce it. You may find that you do better on The Perfect Health Diet, or following this Body By God. Or, maybe you do better on strict Paleo or Primal. Once you know for certain how your body reacts to certain foods, it'll be a lot easier to explain to friends. "Oh no, black beans and rice really screw up my digestion! Please pass the Kerrygold and marrow!"