Do you tell your doctor you are a marathon runner, even though you only run to the refrigerator from the couch?
Researchers studied more than 4,500 responses to a national survey and 60 to 80 percent say they have lied to their doctor.
More than a third reported not speaking up when they disagreed with their doctor's recommendation.
The biggest reasons given for lying included fear of judgment for bad behavior and being embarrassed to tell the truth.
Researchers say a doctor's style of communication may be why some patients are hesitant to open up.
Younger women who self-reported to be in poor health were more likely to report stretching the truth.
The study consisted of responses from online surveys from two populations: 2,011 people whose average age was 36 and 2,499 whose average was 61.
The researchers say they would like to repeat the study and talk with patients immediately after a doctor's appointment.
The study was conducted by researchers at University of Utah Health, Middlesex Community College in Massachusetts, University of Michigan and University of Iowa and published in JAMA Network