What is the “paleo” diet — is it healthy?

DEAR DOCTOR K: My daughter and several of her college friends are on the "paleo" diet. What is that? Is it healthy?
DEAR READER: The paleo diet, short for "Paleolithic" diet, restricts what you eat to foods the hunter-gatherers of the Stone Age ate 10,000 years ago. While the diet doesn't require you to live like a caveman, it does require you to eat like one. Here's an example of what you can and can't eat on the paleo diet: