As for a city breakdown, the majority of Auckland and Dunedin residents also lied about the amount of physical activity, while those in Wellington, Christchurch, Hamilton and Tauranga were less likely to tell the truth about their alcohol intake.
Those surveyed also admitted to lying to their partner about the same issues - with men and women lying about their diet.
Southern Cross Health Society head of clinical operations Geoff Searle says if there's one person you should be truthful to "it's your doctor".
"You might think a white lie here and there won't hurt, but it could seriously hurt your chances of a long and healthy life."
The survey found that shame and embarrassment were the main factors stopping people from talking honestly and frankly with their doctors.
Lying about your exercise levels, how much you drink or smoke, or deliberately omitting some of your medical or family history will limit your doctor's ability to give you the best health treatment, advice and to screen appropriately for a number of problems, says Taradale Medical GP Dr Mark Peterson.
"Doctors with a bit of experience are not going to be shocked or embarrassed by a patient's admissions about their lifestyle -- we have come across most things before. It is much better to be upfront to begin with because the truth usually comes out in the end," Dr Peterson says.
"Our Code of Ethics means that anything you disclose to your doctor will remain confidential and will only be shared with other health professionals with your permission.
"What's important is putting aside any embarrassment and being honest about your health - this is the only way to make sure you'll get the timely advice and treatment you need."