If you're gearing up for an enema after this year's holiday feasts, you might want to think twice, says columnist Virginia Coren in the Observer. A new study says they don't do much good and may do a lot of harm. But why on earth did we every think they did? "Facials don't give you better skin. Seaweed wraps don't make you thinner. Electric shocks don't melt your cellulite." So why do we follow the back-and-forth articles, promising and then debunking? "What we seem reluctant to accept is that nobody can make you beautiful. Except perhaps a surgeon, and that's debatable."