That IS interesting! p119 of the book...he very clearly states that USDA organic is preferable to grassfed, primarily I think because grassfed has no legal definition or verification?
I just bought 1/4 grassfed cow. Not organic, but from a small farmer who I believe practices organically just doesn't want to go through the expense of certifying. So knowing the source, I feel confident that it's better than any grain fed USDA organic. And I think I feel the same buying from reputable places like Whole Foods. So I'll stick with grass fed, but now with more thought to WHERE it's coming from.
Zone diet on and off for several years....worked, but too much focus on exact meal composition
Primal since July 2010...skinniest I've ever been and the least stressed about food