The cereal that the character promotes, Sugar Puffs, has been banned from claiming it contains 'honey goodness' – as honey is just as bad for the body as sugar.
The Advertising Standards Authority ruled that the boast amounts to a bogus health claim.
Sales of honey are soaring, apparently because of the belief that as a natural product it is better for you. But health experts point out that once honey is consumed it behaves the same way in the body as sugar.
The advert on the cereal's website carried the claims: 'Yummy Honey Goodness For A Monsterfied Breakfast... 20% More Honey'.
This idea that the cereal – which contains 8.6 grams of sugar per 30g serving – was full of goodness was backed up by claims that it was low in fat and salt and a good source of fibre, vitamins and iron.
The ruling came after a complaint by the Children's Food Campaign, which said there was no specific authorised health claim to back up the honey goodness line.