Large waistlines could be a result of having spent too many hours glued to television, a new study says.

Study authors also point out how children need to be spending more time playing rather than watching television, something that experts have been saying for years.

"We already knew that there is an association between preschool television exposure and the body fat of fourth grade children, but this is the first study to describe more precisely what that association represents," Dr. Linda Pagani, from the University of Montreal, senior author of the study explained.

The study results are based on analysis of more than 1,300 children and their parents from the Quebec Longitudinal Study of Child Development database. The researchers found that 15 percent of the children aged around 4 years old were watching more than 18 hours of television per week.

The researchers then analyzed waist size of the children. The results showed that children who watched more than 18 hours of television per week, when they were around 4 years old, had larger waist size by the time they were 10 years old.

The children who watched 18 hours of television had a larger waistline by .76 centimeters, or around 0.3 inches, because of their lifestyles at 4 years of age. The children who watched, on average, around 8.82 hours of television had an added .41 centimers, or .16 inches, to their waistline by the age of 10.

"Parents were asked about their child's TV habits. Trained examiners took waist measurements and administered the standing long jump test to measure child muscular fitness. We found, for example that each weekly hour of TV at 29 months of age corresponds to a decrease of about a third of a centimeter in the distance a child is able to jump," Dr. Pagani said.

Previous research has shown than kids are spending a lot of time indoors rather than playing outside. Experts recommend that kids require an hour of physical activity every day and no more than 2 hours of television per day.

"The pursuit of sports by children depends in part on their perceived athletic competence. Behavioral dispositions can become entrenched during childhood as it is a critical period for the development of habits and preferred activities. Accordingly, the ability to perform well during childhood may promote participation in sporting activities in adulthood," said Dr. Caroline Fitzpatrick, lead author of the study.

Center of Disease Control and Prevention (CDC), says that 12.5 million children and teens are affected by obesity which is nearly 17 percent of children in U.S. According to the agency, children are getting heavier than ever. In the past few years childhood obesity has almost has tripled.

Researchers say that people all over the world have started eating unhealthy processed food. Recent studies have shown that spending too much time watching television can reduce a person's age by almost two years.

"Across the occidental world, there have been dramatic increases in unhealthy weight for both children and adults in recent decades. Our standard of living has also changed in favor of more easily prepared, calorie-dense foods and sedentary practices. Watching more television not only displaces other forms of educational and active leisurely pursuits but also places them at risk of learning inaccurate information about proper eating…," the researchers said in a statement.

A recent study had suggested that watching TV can decrease self-esteem in black boys, black girls and white girls but increase self-esteem in white boys.

"The bottom line is that watching too much television – beyond the recommended amounts – is not good," Dr. Pagani said.

The study was published in the International Journal of Behavioral Nutrition and Physical Activity.