According to a new study, obesity decreases the amount of physical activities a person can indulge in over time.

While many studies have been conducted in the past on how physical activities influence obesity, no studies have been conducted on the reverse action, i.e. to see how obesity effects physical activity.

Larry Tucker, a professor from Brigham Young University conducted a study to analyze the other side of the equation and found that obesity, like everyone assumes, does indeed decrease the amount of physical activities a person indulges in with time.

"Most people talk about it as if it's a cycle," Tucker said, senior-author on a study appearing online ahead of print in the journal Obesity. "Half of the cycle has been studied almost without limit. This is the first study of its kind, in many ways, looking at obesity leading to decreases in physical activity over time."

Tucker conducted his research with the help of an accelerometer, which is used to measure physical movement and intensity of activities. This accelerometer was attached to 254 female participants.

"Roughly 35 percent of the population reports that they're regularly active," Tucker said. "When you actually put an accelerometer on adults and follow them for many days, only about 5 to 7 percent are actually regularly active. We used an objective measure so we could determine genuine movement, not just wishful thinking."

Out of these 254 female participants, 124 were considered obese. These obese participants were asked to wear the accelerometer for seven successive days at the beginning of the study, and then again for an additional week, 20 months later, at the end of the study. It was found that over the course of 20 months, the accelerometer recorded an 8 percent drop in physical activities of these obese participants.

"It's not rocket science, and it's very logical," Tucker said. "It just hasn't been studied using high quality measurement methods and with a large sample size. This provides scientists with more ammunition to understand how inactivity leads to weight gain and weight gain leads to less activity. This cycle, or spiral, is probably continuous over decades of life."