Efforts to keep insurance premiums down have led one in four people to tell lies about their lifestyle habits, according to insurer Axa.
Previous medical conditions, weight, alcohol consumption, smoking, depression and minor back problems are all high on the list of subjects to avoid.
While half said they had been too embarrassed to reveal such personal information, 17% admitted they thought their application would be rejected if they were honest.
And it was fear of hefty premium increases that kept most people quite about such things as high blood pressure, high cholesterol and past drugtaking.
Iain Mallon, head of protection at AXA, said: "Most people quite rightly assume that insurance premiums are based on medical histories and certain lifestyle elements.
"What people wrongly assume is that these criteria are based on those of a perfect person, one with a healthy lifestyle and no medical problems.
"In the UK, 53% of people are overweight, one in five suffer from depression, 80% suffer from some form of back pain and 50% of people have high cholesterol, which shows that the perceived perfection is not necessarily the average upon which insurance comparisons are based."
© The Press Association 2008