It was a slow day at work, and going through my bookmarks, I found this article by Michael Pollan in the NYTimes magazine.
I generally avoid articles that tell you what you 'should be eating', and the dire dire consequences of not doing so, but I have been meaning to read his book, and had some time on my hands. And the gist of the article seems to be exactly what I am trying to do: eat mostly plants. He says:
Don’t eat anything your great-great-grandmother wouldn’t recognize as food. (Sorry, but at this point Moms are as confused as the rest of us, which is why we have to go back a couple of generations, to a time before the advent of modern food products.) There are a great many foodlike items in the supermarket your ancestors wouldn’t recognize as food (Go-Gurt? Breakfast-cereal bars? Nondairy creamer?); stay away from these.
Here's the picture I think of when I think of my great-grandmother Olga:

I get the feeling that great-grandma Olga, rocking the opera-length gloves in turn-of-the-century Budapest, probably ate a lot of things that I would not consider to be food. Organ meats? Cabbage? Dumplings stuffed with organ meats and cabbage?
I get what he's saying, though the five-ingredient limit would rule out things like granola and Tasty Bites, which I love.
The most recent picture I have of Olga is this one:

That's great-grandma Olga, grandma Gladys, mom Amy, and me, age one. I love that we are all gathered around my grandparents' dining room table. I imagine that we'll be eating soon.