If you're not familiar with "Nutrition & Metabolism", it's an 
interesting publication. In their words, "an open access, 
peer-reviewed, online journal focused on the integration of nutrition, 
exercise physiology, clinical investigations, and molecular and 
cellular biochemistry of metabolism". I checked it out because Mary C. 
Vernon (the M.D. in Kansas who is very busy curing type 2 diabetes 
with low-carb diet) mentioned it in a video. Michael Eades and Richard 
D. Feinman are on the editorial board, so there's a lot of good stuff 
for paleo dieters.

Here is a link to an awesome article in the journal on protein 
requirements that's worthy of close consideration:

http://www.nutritionandmetabolism.com/content/6/1/12

Hilary