Unless you eat them quickly enough you will find that your bores will glaze. The NHS is not particularly geared up to this obscure form of self abuse, so use Senna or ex-lax to combat it. Or a left-handed 12mm reaming tool.
Hope this helps,
Dave
Body fat's much more useful for soap making though. I've used the grill pan leavings for making soft soap with the kids, and I doubt human fat's much different from pork fat.