PART I: What Should I Eat?
RULE #8 - Avoid food products that make health claims.
This sounds counterintuitive, but consider: For a product to carry a health claim on its package, it must first have a package, so right off the bat it's more likely to be processed rather than a whole food. Then, only the big food manufacturers have the wherewithal to secure FDA-approved health claims for their products and then trumpet them to the world. Generally, it is the products of modern food science that made the boldest health claims, and these are often founded on incomplete and often bad science. Don't forget that margarine, one of the first industrial foods to claim it was more healthful than the traditional food it replaced, turned out to contain transfats that give people heart attacks. The healthiest food in the supermarket - the fresh produce - doesn't boast about its healthfulness, because the growers don't have the budget or the packaging. Don't take the silence of the yams as a sign they have nothing valuable to say about your health.
"Eat food. Not too much. Mostly plants."