I have some good and bad news for you. The good news is, that's it's really easy to stay healthy and lose weight. Eat less, exercise more. The bad news is, to lose weight and stay healthy, you've got to eat less, and exercise more. There's really no other way to do it, no matter how many times you read Eat Right for Your Blood Type. Today, we're talking to Deirdre Barrett about her book "Waistland," the evolutionary reasons for the current obesity crisis, and she's got some interesting info for you. In her history of human health, she details the idyllic life of a hunter-gatherer... more fresh salads, more time with the kids, and tons of fulfilling leisure activities. In any case, if you're...er...human, you've probably experienced that crisis of brain and belly: brain shouting "spinach" and belly growling "steak sandwich, please."