It really helps to read both books all the way through. If you want easy to undestand reasearch and dietary guidelines, chack out Weston A Price's website. He researched primitives and their diets all over the world and his findings are amazing in what they reveal about the secrets to life and longevity.
YES there is a difference between 'free range' 'organic' and 'grass fed'!
Yes, it's more expensive, but worth it. But DON'T waste your money at the health food store unless it specifically states 'grass fed'!
I'm going to start a topic about this because no one seems to know the difference. I'll leave you with some links to pages that show the difference between grass fed and grain fed, and links to online meat stores.