Just in time for New Year’s resolutions, a new study in the prestigious Archives of Internal Medicine has reported on the relationship between our TV habits and weight (Otten JJ, et al. Arch Intern Med. 2009 Dec 14;169(22):2109-15). The average American adult watches 5 hours of TV per day. This is kind of astonishing when I think about all the people I know who watch very little (or no) TV, so to get that “average” number of 5 hours per person it means that lots of folks must be watching a lot more than 5 hours a day! While a number of previous studies have shown that the more hours of TV you watch, the higher your risk for being overweight, this study is one of the first to actually study what happens when people deliberately cut down on their TV watching.

The study took overweight adults who reported watching at least 3 hours of TV daily and randomized them to a control group (observation only) or an intervention group that had their baseline TV watching cut in half by an enforced electronic “TV lock” system. The study reported that people in the intervention group increased the number of calories they were burning each day and slightly decreased how many calories they ate, thus decreasing their overall energy balance by over 200 calories per day. Because they were burning more calories than they were eating, they lost weight and dropped their BMI by 0.25 points, even though the study was a very short 3 weeks in length. All this just by reducing TV time by 50%!

It is astonishing how much just a small change in “calories in” or “calories out” can make in your long term weight balance. A mere 100 calories a day more than what you need to maintain weight and you’ll gain ~7-10 pounds per year. On the other hand, if you burn an extra 100 calories per day (maybe by turning off that TV set) and don’t change what you eat, you’ll lose ~7-10 pounds in a year. So, if weight loss or being more active is your goal, consider turning off the TV on a regular basis. And when you do have the TV on, make sure you stand up and do some quick exercises during every commercial break! Evidence now suggests you’ll likely be very happy with the results.