You should start the excerpt earlier to explain what is meant by EOC:
The starting point of the heuristic is to pose the evolutionary optimality challenge:
(EOC) If the proposed intervention would result in an enhancement, why have we not already evolved to be that way?
Gwern discusses these on his drug heuristics page.
I recently came out against paleo in the open thread, and realized that I probably haven't yet heard the strongest arguments in favor of a paleo diet. So, what are said arguments?
EDIT: Or more generally, why should I eat less carbohydrates and more protein / fat?