Hey [@Framing A Moose], I'd say that regenerators can survive indefinitely without food, water, or oxygen. The way I write regeneration is it being a state of perfect cellular cohesion down to the subatomic level. 

This can always be rationalized as them converting ambient atomic matter into energy if it had to be explained, but yah, I'd say regeneration is on the upper tier of healing factors. Personally.

also, I don't want to come off as over familiar, but I'm sure whatever you've written is great, so don't worry too much about it.