It's well known that watching television the whole day can make you couch potato. But, a latest research has revealed that just one hour of television daily is associated with weight gain in children.

Research found that in comparison to their peers who watched television for less than a hour daily, kindergartners and first-graders, watching as little as one hour of television a day were more likely to be overweight or obese.

According to the US Centers for Disease Control and Prevention (CDC), childhood obesity is a nationwide epidemic, and in the last 30 years it has more than doubled in children and quadrupled in adolescents. In 2012, over one third of children and adolescents were overweight or obese.

As per the previous studies children who watch TV in excess are at risk for being overweight. But, these studies didn't look specifically at the link between TV watching and obesity among kindergartners.

To carry out the study, researchers analyzed data from the Early Childhood Longitudinal Survey of 11,113 children who were in kindergarten during the 2011-2012 school year.

The team looked onto factors, including the number of hours of television children watched on weekdays and weekends and how often they used computers. Further they also measured their height and weight.

After a year, they measured 10,853 of the children's height and weight again, and asked their parents about their child's TV habits.

As per the results, US kindergartners watched an average of 3.3 hours of TV per day. Researchers found that both kindergartners and first-graders who watched 1-2 hours or over two hours daily had considerably higher BMIs as compared to the ones who watched less than 30 minutes or 30-60 minutes a day.

Researchers were surprised to see that in both kindergarten and first grade, children who watched just one hour of TV daily were 50-60% more likely to be overweight, and 58% to 73% more likely to be obese than the ones, who watched less than an hour.

Overweight means having a body mass index (BMI) between 25 and 29.9, while obese is defined as having a BMI of 30 or higher.