Most people lie to their doctors! That’s the upshot of a huge new study of 3,000 patients, doctors, and nurses. But experts say that lying – or omitting information about your symptoms and habits – can lead to a wrong diagnosis and treatment. And could even be fatal!.

Researchers found that patients regularly tell their doctors, “Sure I eat healthy and exercise! I take all my pills as prescribed!” But they don’t. Plus, patients regularly forget to tell their doctor about the supplements and alternative medicines they take, which can react badly to prescription drugs. Researchers also discovered that men lie twice as often as women.

So, why do patients lie? Experts say some people are too embarrassed to tell the truth. Others play up their symptoms – like back pain – to get controlled substances, like Vicodin, or a handicapped parking permit. While other patients play down their symptoms because they’re scared they’ll find out they’re really sick. Or they worry their insurance company, or the cops, will find out what they’re up to.

Know this: Whatever you tell your doctor is confidential. But the lies are so common, that no matter what a patient says about their alcohol, cigarette, and illegal drug consumption, doctors double it. And often adjust their treatment accordingly. Some doctors even look for signs of lying, including avoiding eye contact, long pauses, and anxiety. And doctors lie to their patients, too – 1-in-10 admit it. Half the time they tell a patient their diagnosis isn’t as bad as it really is. And 20 percent won’t admit a mistake.

So, it’s in your best interest to tell them the truth, and to ask the doctor to be straight with you, too. Otherwise, you’re wasting their time, your money. And putting your health at risk.

What do you think: Is it okay to fib to your doctor, if it’s just a small one? Have you ever done it?