Rampant, completely unsubstantiated speculation that is probably contradicted by the evidence: I wonder if we'd be even more fat if we didn't switch. Switching slows down your eating, and I know that there is data to show that slower eating means you eat less. I guess the foods we eat too much of that are really bad for you, like snacks, sandwiches, and sodas, don't take a fork and knife at all.

That said, my wife and I are eating out French tonight, so I'll try to put down my guilt and manners and not switch hands!