Recently I was with someone I know at a health care facility for treatment for a minor issue. During the normal intake process the medical assistant reviewed the patient's health history, current medications and symptoms. When the medical assistant asked the patient if they smoked I was shocked when the patient said no. I had seen this person smoking a cigarette just an hour before. Sadly, it is not uncommon for patients to be "less than truthful" to doctors and other healthcare providers.
Sometimes it may be tempting to lie to your doctor. This is especially true for things that the patient knows they should not be doing like smoking or eating an unhealthy diet, or something they should be doing like exercising more or following a specific care plan. It can be hard to admit that you didn't do what you know you were supposed to do. However, lying, exaggerating or withholding information from your healthcare providers is just a bad idea.
First and foremost, not telling the truth could allow a physician to prescribe a medication or order a test or treatment that is dangerous for that patient. A physician could easily misdiagnose something without understanding the full picture. Plain and simple: if the doctor doesn't have an accurate understanding of the patient's history and current facts they can't effectively treat them. Furthermore, depending on the lie, they may know that the patient isn't telling the truth. For example, there is a good chance when the doctor examined that patient who lied about being a smoker he noticed the smell of smoke in the patients clothes, hair and breath. Test results and other symptoms may also lead the doctor to discover the truth. It's better not to undermine your credibility and make the doctor guess the truth.
Sometimes patients choose not to tell the truth because they fear that they will be scolded or lectured by the healthcare provider. This is a legitimate concern. If you already feel badly about the issue you can feel worse if you have to talk about it with your healthcare provider. This is especially true if you've already discussed it multiple times.
As I've written before, you don't have to participate in a conversation with any healthcare provider if you don't want to. While it is generally a good idea to listen to and engage in conversation with your healthcare providers when they make recommendations, you can simply say "I'm not going to discuss this with you right now". If you feel you already have the information you need and/or the conversation is disrespectful or uncomfortable for you it might be appropriate to stop the conversation. You have that right. However, consider that it may be an opportunity to discuss the problem more deeply with your healthcare provider, and to look at why you have not complied with the recommendation and find a new approach to help you comply. Whichever way the conversation goes it is better for your health and well being to let the doctor know the facts so that you can receive the best care possible for your situation.
Remember that there is a reason why healthcare information is kept confidential. There are special laws in place to protect patients from having their information shared or used against them. The interaction between patient and healthcare provider must be safe for it to be effective. If there is a part of your healthcare history that you find particularly sensitive you can request additional confidentiality protections through the medical records department at a facility. It is your right and obligation to be as truthful as possible with your providers and their obligation to evaluate the facts make sure your information remains confidential.