People who spend more time on computers are more likely to be obese—even if they exercise weekly, according to a study published in the Journal of Medical Internet Research and reported by Rodale.

Researchers surveyed 2,650 Australian adults about their physical activity, Internet and computer use and other sedentary activities. (Internet use and physical activity were divided into three categories none, low and high.)

Investigators found that individuals with the highest computer usage were 1.5 times more likely to be overweight and 2.5 times more likely to be obese. These study participants also reported doing less physical activity and engaging in more sedentary activities.

“People who use the Internet a lot also engage more in other sedentary behaviors, and that is likely the main cause of their being more likely to be overweight,” said Corneel Vandelanotte, PhD, a postdoctoral research fellow at the Institute for Health and Social Science Research at Central Queensland University.

But results also showed that participants who had high computer use and high levels of physical activity were still almost twice as likely to be overweight or obese than people who didn’t spend any time on the computer.

How is this possible?

“If I go running three times a week for one hour, but watch TV the rest of my time, I will still be very sedentary,” Vandelanotte said. “I might be fit, which is definitely a good thing, but it might also be that I’m still not spending enough energy on a daily basis.”

The American College of Sports Medicine recommends 2.5 hours of exercise a week to avoid gaining weight and 4 hours a week to lose weight.

Oh, and turn off that computer.

Find out why nearly half of all African-American adults are obese here.