Generally speaking I agree. It's best to stick with "fruits of the earth" which to me includes herbs that grow naturally. (As long as we stay away from the poisonous plants!).

I don't agree with the part about Amish food though. I avoid meat and dairy. And the Amish use far too much Sugar / heavy desserts in their cooking.

Personally I rely on what I read / study and my instincts. I think if we listen to our "inner voice" that it will tell us what we need.