Haha, its hilarious to hear paleo people state that they can't have a bowel movement when they're eating "low carb". Well, hmmm, let's think about it...fiber is a carb, so low carb means low fiber.
But they brush it aside as a low toxic load and the body absorbing everything, so there is nothing to eliminate.
Others even state that you merely need more fat. This does nothing for the intestinal flora. You need carbs to feed and keep the flora healthy.
But Paleo can actually be a decent diet if done properly in my opinion. You just have to consume ample amounts of fruit to make up for the oil calories that you should not be consuming.