The Feasibility of the Human Centipede?

Yes, I know what I'm asking is ridiculous, but watching this movie got me thinking: is it possible for a person to survive on feces? My understanding has always been that digestion, at that point, has taken the bulk of the nutrients from what was first ingested, and it seems difficult to fathom that being able to sustain a person- much less after it's been digested twice. Thanks for humoring me on this one!