A Which? report published last week, Childcatchers - the tricks used to push unhealthy food to children, found more than 40 different examples of ways food companies market products to children.
The group said that while some techniques are obvious, such as TV advertising, there are many more 'underhand' methods. Examples include websites, video games and mobile phones.
The report cites the Neopets website, which includes a game in which children earn points to maintain the health of an online virtual pet by playing a Pepsi World game.
Children are also being targeted through 'text 2 win' competitions, such as one run by Fanta in 2003 to win a mobile phone, the report says.
Computer games include some versions of The Sims in which players running a McDonald's kiosk earn points for eating burgers.
Which? chief policy adviser Sue Davies said it was difficult for parents to protect their children from such techniques.
'While at home, shopping, playing and at school, children are constantly bombarded with calculated messages encouraging them to eat more junk food.
Such reckless marketing undermines efforts to improve children's diets.
Irresponsible marketing of foods high in fat, sugar and salt to children has to stop. This is crunch time for the industry. If it fails to act, the Government must stick to its pledge to legislate.'
The report is available online at www.which.co.uk.
