Which? carried out research showing that 77% of people think that using kids' favourite cartoon characters on the packaging of foods that are high in fat, salt and sugar makes it difficult for parents to say no to their children.
It has singled out characters including DreamWorks' 'Shrek', who was used to promote Nestle's Mud and Worms breakfast cereal; Twentieth Century Fox's 'The Simpsons', whose name has been licensed to a range of Tayto corn snacks; and Hasbro's Action Man, licensed to tinned pasta shapes in tomato sauce made by HP.
Disney also comes under fire for licensing the characters from 'The Incredibles' to another Nestle breakfast cereal, The Incredibles Nestle Golden Nuggets, which is high in sugar and salt.
Nick Stace, campaigns and communications director at Which?, said: "Too many characters loved by children are being used to promote foods high in fat, sugar and salt, leaving their parents feeling powerless to say no."
It is calling on the Food Standards Agency to establish a standard for responsible food promotion to children, and also for the companies that own the characters to be more responsible about what foods they endorse.
According to The Independent, Twentieth Century Fox has said it was reviewing its policies on product endorsements. Warner Brothers, which owns Scooby Doo, has argued that it works with many branded food partners that develop products with signficant nutritional value.
The FSA has already considered the issue of the way cartoon characters are used to market foods impacts on what children eat, as part of a wider investigation into the problem of obesity.
The Department of Health White Paper on the issue, published last November, fell short of calling for a ban on junk food ads or celebrity endorsements, but it did call for curbs. However, this does not extend to non-advertising promotions of food.
Last year, the Advertising Standards Authority ruled against Kellogg for a Frosties ad featuring Tony the Tiger. The watchdog said it must not use the claim "eat right" again in ads for Frosties, because Frosties have a high sugar content and the ad, showing children playing football, implied the product was healthy.
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