I keep seeing things about how fasting isn't paleo because the paleolithic was an environment of abundance. So? So is Brooklyn, that doesn't mean we eat all the time.
Ever just not feel like cooking? Ever plan your day badly and end up skipping breakfast? I wouldn't be surprised if hunter-gatherers did the same. After all, butchering animals IS tough work.
So I'll just reference one of my old posts on Daniel Everett's book Don't Sleep There Are Snakes, which is about the Pirahã tribe: "They have no food preservation methods and simply eat when they have made a kill. Apparently being hungry is no obstacle to exerting themselves: "I have seen people dance for three days with only brief breaks, not hunting, not fishing, or gathering -- and without stockpiled foods."
So fast if you want to, but the idea that fasting is inhuman and damages your metabolism seems bunk to me. Lean Gains has a good post about it. That said, I think fasting is for HEALTHY people. If you are trying to repair your body, eat well and then fast when things are normalized a little better. I also think that fasting should never feel bad. If you are healthy and fasting properly you should be perfectly functional, not obsessed with food, and in a good mood. If you aren't those things...maybe you need to take a step back and nourish yourself first.