Seems like quite a predicament.
I have not yet made or seen something like this yet,
though If no one responds:
Do some research on a all natural low sugar barbque sauce.
Try to buy a very lean part of the pig as certain cuts of pork are very fatty.
as for the bread, there are many alternatives available, such as pita bread and low glycemic index breads.
As I said, I do not know alot about this subject, but I hope that it helps you some