It's probably better to skip dessert, you tell yourself as the waiter brings the check, but let's just take a peek at the menu. Soon you're three spoonfuls into a bowl of vanilla ice cream, and there's a triple-fudge brownie waiting patiently for your attention. You smile in delight with each bite, then twinge with regret for your poor belly. Months from now you'll curse yourself as you sink into a dentist's chair and grasp an armrest with trembling fingers.