Comment »Posted on Wednesday 16 December 2009 at 9:45 pm by Jacob Aron
In Health & Medicine

People restricted to watching half their usual amount of television burned more calories in a three-week period, according to a study published in the Archives of Internal Medicine. Researchers at the University of Vermont found that while cutting back on television didn’t affect the amount of food people ate, it did mean they were more active and burnt an average of just under 120 extra calories a day.

America’s rising obesity crisis has lead to many public health initiatives designed to get the nation eating well and exercising. The researchers suggest that smaller changes in behaviour, like watching less television, could actually have more of an effect on weight loss.

There’s certainly a lot to cut back on. The average US adult watches 5 hours of television a day, making it the most time consuming activity behind sleep and work. Watching TV has previously been associated with risk of obesity, diabetes, and heart disease, and it burns less calories than other low energy activities such as reading or talking on the phone.

To investigate the effects of cutting back on television, the researchers monitored the viewing habits of 36 adults with a BMI between 25 and 50. Each participant reported watching at least three hours of TV per day.

With a baseline set, 20 participants were random selected to have their viewing hours cut in half. A device attached to the television would switch it off once the week’s viewing limit had been reached, and not allow it to be switched back on until the timer reset a week later. Needless to say, the monitors were securely locked away to deter tampering! The other 16 participants served as a control group, continuing to watch the same amount of television.

The results showed a slight reduction in food intake for the 20 participants who had watched less TV, but this was not statistically significant. They did however significantly increase their energy expenditure, burning an average of 119 extra calories a day.

That might not sound like much, but it adds up. Over the course of a year, burning 119 calories a day would result in a weight loss of over five and a half kilograms. It seems that while watching TV won’t turn your eyes square, it does contribute to making your body round.

Otten, J., Jones, K., Littenberg, B., & Harvey-Berino, J. (2009). Effects of Television Viewing Reduction on Energy Intake and Expenditure in Overweight and Obese Adults: A Randomized Controlled Trial Archives of Internal Medicine, 169 (22), 2109-2115 DOI: 10.1001/archinternmed.2009.430

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