In the study, led by Tracy Oliver, MEd, RD, LDN, a Lead Health Services Specialist at Temple's Center for Obesity Research and Education, compared the amount of activity reported by the women to the actual amount of activity as measured by an accelerometer.
Accelerometer is a device that measures movement and acceleration over the course of a year.
The researchers observed that, at the first measurement, and second three months later, obese women most accurately reported the amount of physical activity they were getting.
However, at 12 months, all three groups were reporting on their activity levels more accurately.
"The ability to estimate the amount of minutes engaged in physical activity is a difficult task for many, however the accuracy of this estimate can increase with education and participation in physical activity over time," said Oliver.
The study will be presented at The Obesity Society's annual meeting.