Here's the truth behind those kitschy sayingsMaybe you had a granny whose raspy voice you still hear rattling around your head every time you feel a cold coming on: "Feed a cold, starve a fever." Or, wait, is it the other way around? Family physician Dr. Jeffrey Cain, president-elect of the American Academy of Family Physicians, offered the truth behind such "folk wisdom":

"Feed a cold; starve a fever." This one has medieval roots, first appearing in print in a 1574 dictionary. It's basic common sense: "When people have a fever, they don't want to eat," Cain says. "There's no science behind it, but there's no harm behind it either. The most important thing, though, is to give your body a rest; let it heal."

"Sweat it out." "Sometimes when someone has a fever, they think that if they pile on the pajamas and get under lots of blankets, they will sweat out the virus. There's no science to it. When you break a fever, you will sweat, and as your fever goes down, you'll get chills. But you can't sweat out a virus," Cain says.

"Walking is the best exercise." This goes back to Hippocrates, who claimed walking was "man's best exercise." Says Cain: "When people ask, what's the best exercise, the answer is, 'The one you'll do.' Walking is great, it's easy and you don't need any equipment. Its two special benefits are that it's almost as good for you as jogging, but it won't hurt joints."

"An apple a day keeps the doctor away." "We know Americans don't get enough fruits or vegetables," Cain says, "so I'm all for an apple a day. If you want to take it up a notch, try, 'Be sure your plate is filled with lots of colors, flavors and textures.' Stick to whole foods, in forms as close to all-natural as you can get."