Yes, I knew someone would catch me out in this aspect and it's a very good question.
I suppose a person could just eat all the non-human ingredients which would negate the need for cannibalism which is probably just as well although i think this post would not have been as fun to write if I'd not added in the human-food element.
Fortunately I'm not starving and there's small chance of it happening...although there was this one time between breakfast and lunch when I was so hungry I could have eaten the ass out of a low flying duck.
Fortunately I found some cookies and ate them instead.
RE: All the human good bits