Children consume nearly as many calories as are in a packet of crisps with every hour they spend watching television, according to US research.
Watching TV also encourages children to eat more junk foods, particularly soft drinks and takeaway fast food, the researchers found.
The study is the first to demonstrate that watching television directly influences intake of calories. Its main author, Jean Wiecha, said the survey showed that excessive TV viewing was in itself a health risk.
"The food industry spends billions of dollars on advertising because they know it is effective," she told Guardian Unlimited.
"They talk about fighting for your child's dollars, and the result is additional food going in your child's mouth. The intensity of the viewing looks like it's really driving up intake of the foods being advertised."
The study followed 550 children aged 11 to 13 over a period of 20 months. For each hour they spent watching television, their food intake was found at the end of the period to have increased by 167 calories a day. (A packet of crisps contains around 180 calories, while a can of Coke has 140).
Figures from the communications regulator, Ofcom, show that British children watch 10,000 TV commercials every year, including nearly 3,000 ads for soft drinks, foods and fast food chains.
Ofcom found that British advertisers spend £522m a year on commercials targeted specifically at children, who watch commercial TV for 588 hours each year - the equivalent of 24 days.
Numerous scientific studies have shown that children who watch more TV have a higher calorie intake, but advertisers argue that this is a result of their more sofa-bound lifestyle rather than of the adverts they are watching.
Dr Wiecha, however, said her work contradicted this. "Although children and youth are encouraged to watch what they eat, many youth seem to eat what they watch," the report's authors wrote.
"We've shown that as kids watch more television, they eat fewer fruits and vegetables. Television viewing influences children's diets."
The Guardian reported last week that government manifesto plans to restrict children's food advertising had been watered down after sustained lobbying of Ofcom by advertisers and broadcasters.
TV commercials aimed at children younger than 12 have been banned in Sweden and Quebec, and similar restrictions apply in Belgium, Denmark and Greece.
But a range of proposals Ofcom published last month failed to recommend any restrictions on food advertising to children older than nine, and campaigners said the restrictions for younger children were minimal.
Dr Wiecha's report was published in this month's issue of the medical journal the Archives of Paediatric and Adolescent Medicine.
A study in the same issue found that children exposed to more than two hours of television per day were more likely to be overweight than those who were not.
Source:http://www.buzzle.com/editorials/4-25-2006-94440.asp