Which raises the question … if Mr. Tumnus were a Jewish fawn - could he eat his own legs, and keep kosher? 
But the hindquarters aren’t kosher, so you could only eat his top half.
This brought a few more questions to mind. What kind of digestive system do centaurs have and do they chew their cud?
Given that horses have no cud, and thus do not chew cud, and centaurs are supposed to be half-horse, centaurs likewise would not have cud nor chew cud.
As for digestion - that varies from source to source. In the Narnia books at one point it is explained that their centaurs have two digestive systems, a horse one and a human one, and they eat food for both, which accounts for them getting up very early in the morning to start breakfast as they require both a horse breakfast of things like hay and oats and a human breakfast of whatever humans normally eat in the Narnia books.
Given that, despite what the rest of the digestive system may be, they still have only a human mouth with which to chew and ingest both meals, I suspect the horse breakfast is even more difficult and time-consuming for the centaur than it would have been for the horse to eat. I also have to wonder how the plumbing hooks up - is the system in series or parallel?
Donna Barr explores the issues of centaur anatomy in her wonderful comic books series Stinz. An excerpt
Human doctor “Don’t you do autopsies? Cut up the dead?”
Centaur “Maybe you do such things, but we’re Catholic!”
On the other hand, though, unicorns are sometimes described as having goat-like hooves, and it’s at least plausible that they might chew cud, too.
Unicorns are frequently considered avatars of Christ, so presumably everybody celebrating Mass this morning can be considered to be drinking unicorn blood and eating 'corn steak.
Hmmmm…that kinda adds a new dimension to the thing about how only female virgins can ride a unicorn…
Discussed in a thread of mine from a while back. There’s a couple of ways to look at it, but I don’t wish to hijack this thread further.
The book in question, by the way, is the best of the Chronicles, The Silver Chair. Someone is explaining to Jill why Centaurs take so long to eat breakfast and why asking one to stay the weekend is such a major thing. As the whole thing is a set-up for a joke, I’m not sure if even the character is serious.
Maybe that’s where unicorn as avatar of Christ comes from? I don’t know, I get the lion, pelican, & lamb analogies, but the unicorn analogy is unfamiliar & strange to me.
Tell you what. If you really want to eat Mr. Tumnus, do it. I wont tell.
It’s not polite to eat persons without their permission!