Zombie Physics

Dislike supernatural explanations?
Prefer Zombies that can starve to death?
Does constant disregard for the first law of thermodynamics distract you from enjoying your show?

You're in luck, this is an attempt to provide a fictional "fig leaf" for how the Zombies of The Walking Dead could keep shambling around years later. It's not meant to be a serious attempt at explaining the undead, just enough to give a nitpicker something to handwave away problems.