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COUCH potatoes can take heart from a new study which reveals that watching
television uses up 20 per cent more energy than lying in bed doing nothing.
What鈥檚 more, as far as burning calories is concerned, TV is just as good for
you as more cerebral activities, such as reading or writing.

Researchers at Meharry Medical College and Vanderbilt University in
Nashville built a mock-up of a bedsit inside a giant calorimeter, and sealed
volunteers inside to watch as much TV as they wanted during two 24-hour
periods. Sensors monitored the volunteers鈥� every movement, and the researchers
calculated their energy expenditure by comparing their calorie and oxygen
intake with how much carbon dioxide and urine they produced. The results show
that watching TV uses up around 93 kilocalories an hour 鈥� about the same
amount as other sedentary 鈥渁ctivities鈥� 鈥� compared with the 77 kilocalories
expended while lying motionless in bed.

But that鈥檚 where the good news ends. Even extremely light physical
activity, such as walking at only half a metre a second, uses up 131
kilocalories. 鈥淲atching TV doesn鈥檛 help you lose weight, that鈥檚 for sure,鈥�
says Maciej Buchowski, who led the research. 鈥淚t鈥檚 not an exercise.鈥� In
reality, most of the energy used up while 鈥渨atching TV鈥� goes on associated
activities, such as getting up to put the kettle on during the commercial
breaks or zapping the remote control, he says.

Around 20 per cent of the body鈥檚 energy consumption is taken up by the
brain, even when resting. Thinking does not use up much more than resting,
warns the team. If you replace half an hour鈥檚 TV with a very light stroll
every day for a year, you might avoid putting on 3 kilograms in weight, they
claim in the current issue of the International Journal of
Obesity.