Family doctors think that most patients underestimate how much alcohol they drink, a small poll suggests.
More than seven in 10 GPs (71%) believe that less than half of their patients accurately represent how much alcohol they consume.
A survey of 191 doctors, including 183 GPs, found that on average, GPs apply a 1.6x multiple to the amount of alcohol their patients say they consume.
This includes 32% of GPs who believe that patients actually drink 1.5 times more than the amount they report, and 46% who estimate that patients drink twice the amount they say they do.
The survey, from Direct Line Life Insurance, has prompted leading GPs to urge patients to be honest with their doctor.
The company also surveyed 2,000 British adults and found that 14% admitted that they did not tell the truth about their alcohol consumption because they did not feel it was relevant and the same number were worried their doctor would judge them.
Others said they did not keep track of how much they consume.
Commenting on the poll, Professor Helen Stokes-Lampard, chairwoman of the Royal College of GPs, said: "Over-consumption of alcohol can have a huge negative effect on our health and wellbeing, so being honest with your GP or other healthcare professional, as well as yourself, about how much you drink is an important first step in understanding how it could be impacting your life.
"GPs understand that it might sometimes be difficult for people to keep track of how much alcohol they drink, and that some patients might not want to disclose the amount because they're embarrassed or worried about being judged by their doctor.
"But patients should be reassured that GPs are medical professionals, highly trained to have sensitive, non-judgmental conversations about anything that might be affecting their overall health and wellbeing."
Jane Morgan, business manager at Direct Line Life Insurance, said: "Most of us enjoy a drink from time to time, but no matter how much alcohol you consume it's important to be honest with your doctor about it. Without all the correct information about your lifestyle you may not get the right diagnosis or treatment.
"You should not only ensure you are honest with all medical professionals but if you're asked about how much you drink when purchasing a health or life insurance policy it's important to be truthful on your application so you can ensure you have the cover that's right for you."
Helen Clark, deputy director of drugs, alcohol and tobacco at Public Health England, added: "It's all too easy for the amount of alcohol you drink to creep up on you. That's why it's important people try to keep track of how much they're drinking.
"The Chief Medical Officer's advice is not to regularly drink more than 14 units a week. Some glasses of wine can contain as many as three units of alcohol. Our One You Drink Free Days app is a simple and easy way to help track and reduce your drinking."