If there's anyone you should be honest with, it's your doctor. But according to a recent survey, one-third of Americans lie to their doctors.

Of course, keeping secrets can be dangerous - especially if the information you're holding back leads to a wrong diagnosis.

So, if you're going to lie, at least be smart about it. Here's a rundown of some lies you should never tell your doctor:

"I never smoke." -- Even if you smoke just a couple times a month, you need to 'fess up. Smoking causes many physical complications that your doctor needs to be on the lookout for.

"Nothing has changed since my last visit." -- When your doctor asks "What's new?" he or she doesn't mean only medically. A change in your relationships or stress about work or money are all big, important things to share.

"I'm not taking anything." -- Even if it's just vitamins or herbal supplements, your doctor needs to know what you're ingesting.

"I feel fine." -- About one in eight women struggle with depression at some time, but recognizing that you need help isn't easy. Be sure to tell your physician about any changes in your mood, thinking or behavior that affect your ability to function at home, at work or with your friends.