Food companies have hijacked new technology such as the internet and text messaging to promote sugary and fatty food to children, a report on junk food's "marketing tricks" claims today.
An investigation by the consumers' association Which? found sophisticated use of mobile phones and computers were among 40 "underhand" ways of advertising unhealthy snacks and meals to children.
Aware that 75 per cent of teenagers have home access to the internet, Pepsi sponsored a computer game on a pet website and Masterfoods created a breezy Starburst site carrying showbusiness news. Cadbury received five million responses to a text-messaging competition to win £1m.
Other, low-tech promotions used by firms included star endorsements, games on packaging and the selling of a McDonald's children's play set containing plastic burgers and chicken nuggets.
Publication of the report, Child Catchers, comes amid rising concern about the level of obesity in children. In England, one in seven children under the age of 11 and one in five aged between 12 and 16 are obese, putting them at future risk of diabetes, cancer and heart disease. A consumer backlash has begun in the past 12 months with millions of pounds wiped off sales of the least healthy chocolate bars and crisps.
Britain's biggest crisp-maker Walkers, which lost £30m sales last year, announced yesterday that it is cutting saturated fat in its products by up to 70 per cent. The Pepsi subsidiary will launch a £20m advertising campaign fronted by Gary Lineker.
Television advertising is a controversial issue for the manufacturers. The regulator Ofcom is currently considering banning junk food adverts from children's television - a move that is supported by 70 per cent of parents.
In its report, Which? found evidence that food marketing aimed at children had become more "inventive and integrated" in the internet age.
In an attempt to capture the Net-savvy generation of teenagers, food companies have turned to sponsoring internet games. Visitors to the neopets site, for example, earn points for the health of a virtual pet by taking part in branded contests.
In the Pepsi World game - now withdrawn from the site - a character raced to serve "thirsty" customers "delicious" Pepsi in a Pepsi palace. Nestlé's Lion bars promoted a competition based on The Incredibles film with the prize of a visit to Pixar's animation studios, that could be entered online or by text message.
A competition to win a mobile phone - a popular prize with adolescents - was promoted by Fanta. One product website, mouthwateringtv.co.uk, which is advertised regularly in teen magazines, carries showbiz gossip and competitions. It also has "plenty of Starburst mentions" - a reference to sweets made by the website's owner, Masterfoods. Competitions generate e-mail addresses for future promotions.
Among the less technological methods are the use of puzzles, pictures and games. A game inside a packet of Cadbury Mini Rolls - 46g of sugar per 100g - encouraged children to use the mini rolls as a trading token to get out of doing chores, such as "eating your greens".
Product placement was still popular in films, such as Burger King in Scooby Doo II and Coca-Cola in Madagascar.
Sue Davies, of Which?, said: "While at home, shopping, playing and even at school, children are constantly bombarded with calculated marketing messages encouraging them to eat more junk food. Such reckless marketing undermines efforts to improve children's diets."
She said that the Government should legislate against irresponsible promotion unless the industry drastically improved its performanceReuse content