A new report discovers a reduction in television time among adults leads to burning more calories.
Although caloric intake did not change, the increased energy burn and replacement of a sedentary behavior with an active lifestyle bodes well for a sustainable long-term approach to combat obesity.
The study is reported in the current issue of Archives of Internal Medicine.
The average adult watches almost five hours of television per day, according to background information in the article.
Efforts to prevent and reduce obesity have focused on modifying diet and physical activity, but newer strategies have involved reducing sedentary behaviors such as TV watching.
Switching a sedentary behavior to an active endeavor may also improve sleep and indirectly combat obesity.
In the study, Jennifer J. Otten, Ph.D., R.D., and colleagues conducted a randomized controlled trial of 36 adults who had a body mass index between 25 and 50 and reported watching at least three hours of TV per day.
Between January and July 2008, all participants underwent a three-week observation period during which their daily TV time was assessed.
A group of 20 individuals was then randomly assigned to receive an electronic device that shut off the TV after they had reached a weekly limit of 50 percent of their previously measured TV viewing time. An additional 16 participants served as a control group.
As assessed by an armband measuring physical activity, those with the television lockout systems burned 119 more calories per day during the three-week period. In comparison, the control group burned 95 fewer calories per day during the intervention than during the observation period.
Energy balance—energy intake minus energy expenditure—was negative in the intervention group (by 244 calories per day) but positive in the control group (by 57 calories each day); however, this difference did not reach statistical significance.
“A recent task force report supports small behavior changes as a more sustainable, long-term approach to help address the obesity epidemic,” the authors write.
“It has been estimated that combined increases in energy expenditure and decreases in energy intake equaling only 100 calories per day could prevent the gradual weight gain observed in most of the population.”
Previous research with children has found that screen time reductions reduce calories consumed but do not increase calories burned, producing a similar change in energy balance but through a different mechanism, the authors note.
“This suggests that adults may differ from children in how they respond to reductions in sedentary behaviors,” they conclude.
“To our knowledge, this is the first study to measure the effects of a TV reduction intervention in adults. Reducing TV viewing should be further explored as a method to reduce and prevent obesity in adults.”