I've heard that for people who are trying to add muscle, fasting is generally not recommended. I never really understood why, because conceivably you could get enough calories (say, 3000) with one huge meal per day. Also, doesn't fasting help your body secrete growth hormone? Wouldn't that help the cause?
The high-fiber high-protein paleo diet lends itself to a slow amino acid release that can make fasted training very effective.
Definitely check out this article over at leangains.com: "Fasted Training Boosts Muscle Growth?" http://www.leangains.com/2009/12/fasted-training-boosts-muscle-growth.html
Leangains has a system that takes advantage of the hormonal effects (increased growth hormone and insulin sensitivity). He advocates 16 hr fasts, uses amino acid supplementation to prevent protein breakdown during exercise, and high intensity exercise to boost GH.
If you browse his site, some of his articles are quite technical. And he is no way paleo, but I feel his approach adapts well well with a "modernized" paleo.