How much do you really drink? Do you always use condoms? How many vegetables pass your lips in a day? If you don't always fess up to your less-than-perfect health habits, welcome to the club. Almost everyone stretches the truth at least a little when their doc asks about lifestyle habits. 

"For the most part patients don't want to lie to their doctors—they view it as 'sugarcoating' the truth or 'conveniently forgetting' details because they don't want to look bad or be embarrassed," said Dr. Kristine Arthur, an internist at Orange Coast Memorial Medical Center in Fountain Valley, CA. But these seemingly small fibs can have huge health implications.

Here, the 7 most common things folks lie about, and why they matter. (Lose up to 15 pounds in just 3 weeks by balancing your weight-gain hormones—here’s how!)

Their diet

"Often people with diabetes, high cholesterol, or obesity will say that they don't eat anything 'bad' and can't understand why their labs are still abnormal or they aren't losing weight," Arthur said. "When asked point-blank if they are eating saturated fats or processed sugars, for instance, they often say no even when their labs tell another story."

But it's imperative that you be upfront with your doctor whether you have high cholesterol or any chronic illness that requires a modified diet (if you have high cholesterol, these 12 foods can help you lower it naturally).

Their alcohol intake

"Nurses know that if someone says they have two to three glasses of wine per week, it's often two to three per day," said Teri Dreher, RN, a patient advocate in Chicago. "I've had hundreds of patients tell me they drink just a little bit here or there and their family tells me that they get drunk almost every day."

(Could you have a problem without knowing it? Here are 6 sneaky signs you’re drinking too much.) But if you're not honest about how much you're imbibing, it can lead to over-testing and possibly even dangerous drug interactions.

"If your liver test is abnormal and you deny alcohol use, it could trigger a workup that may be unnecessary," Arthur said. "Many medications also should not be taken with alcohol and it's important that we know that when prescribing them."

Severity of symptoms

When Kashif Ali, a medical oncologist with Maryland Oncology Hematology, starts a cancer patient on a treatment regimen, he discusses all the possible side effects that can occur, including life-threatening ones that would require stopping therapy.

"Unfortunately, patients sometimes lie and mask certain troubling side effects out of fear that I may discontinue that particular treatment," he said. "But oftentimes they can stay on the regimen, as long as I adjust the dose, or even switch to another treatment that's just as effective."

MORE: The 10 Most Painful Conditions

Or, the opposite: "Sometimes patients, especially older ones, feel the doctor will not pay attention to them unless they exaggerate their symptoms," Dreher said. "Often doctors seem rushed and don't make a lot of eye contact because they're also typing into a computer, so people worry that they won't get the doctor's attention unless what they say is very striking."

But crying wolf may just make your doctor less likely to take you seriously when something is really bothering you.

Their medications

This is a big one. "If you ask patients if they're taking their medication as prescribed, most of the time they'll automatically say yes," Arthur noted. "Upon further questioning, they may admit that they forget the evening pills or didn't get to the pharmacy for a couple of weeks to pick up their medication." Sometimes patients say they're taking their meds now, "however, it can take some digging to get the full story, which is that they stopped for a couple of months and only restarted them yesterday before their appointment." 

Your doctor would much rather be aware that you haven't taken your prescription so that perhaps it can be restarted with the hope that this time your labs, tests, and symptoms improve.

Ditto with other, non-drug treatments like physical therapy: If you don't fess up to your MD that you're not following the program, it can not only delay healing, it may lead your doctor to unnecessarily prescribe other, more aggressive treatments like medication or surgery, according to Dr. Steve Yoon, a physical medicine and rehabilitation physician at Kerlan-Jobe Orthopaedic Clinic in Los Angeles.

Unprotected sex

"One of the most common lies I hear among all my single sexually active patients, no matter what their age, is 'of course my boyfriend always wears a condom every time we have sex'," said Dr. Sherry Ross, an OB/GYN at Providence Saint John's Health Center in Santa Monica, CA. "But condoms are the best way to help prevent sexually transmitted infections, pregnancy, HIV infections, and HPV-related diseases such as genital warts and cervical cancer, no matter what decade you're in." (Here are 7 things you should never do before or after sex.)

Women who find themselves back on the dating scene in mid-life may be especially nonchalant about using condoms, in part because they're no longer worried about preventing pregnancy. But according to CDC data, rates of sexually transmitted diseases are on the rise across all age groups. In their 2014 survey, chlamydia was up 2.8 percent and syphilis was up 15 percent since 2013. 

Drug use

And we're not talking about Advil and Robitussin.

"I have some male patients who deny being on testosterone therapy, which is important to know because it reduces fertility," said Dr. Philip Werthman, director of the Center for Male Reproductive Medicine and Vasectomy Reversal in Los Angeles.

But testosterone therapy won't only mean shelling out thousands of dollars in out-of-pocket infertility expenses—research also suggests a link between taking T and heart disease.

The same holds true for other, recreational drugs like marijuana.

"People don't want the drugs on their official medical records for fear of repercussions from work or insurance companies if they were to ask for them, but they can also cause fertility related issues like low sperm count," Werthman said. 

Cosmetic surgery

"I'm always amazed at how many patients say 'no' when asked if they've ever had surgery, but then somehow it slips out at a subsequent visit," said Dr. Nieca Goldberg, medical director of NYU Langone's Joan H. Tisch Center for Women's Health.

Yes, you may be mortified at the idea that your physician knows you went under the knife, but it's important to learn if you had any post surgery complications or reactions to anesthesia, in case you ever require an emergency operation.

This article originally appeared on Prevention.com.