The children's television network Nickelodeon is to curb the use of its characters on the food packaging of items that are deemed not healthy enough.

The network, which is owned by Viacom, said that any new licensing deals for its characters, which include SpongeBob SquarePants and Rugrats, will have to meet dietary requirements based on governmental guidelines.

The policy will become effective with deals from January 2009.

The move was announced in a letter from Viacom executive Cyma Zarghami to Rep. Edward Markey, a Massachusetts Democrat and chairman of the House telecommunications committee.

According to the letter, the company has not ruled out using its licensed characters on holiday treats.

The announcement comes in the same week as news that US food group General Mills has launched a healthy-eating educational programme for children around its Green Giant brand under the banner Mighty Giants, in association with Nickelodeon.

The company said the iniative is designed to help parents get their children to eat healthily. A special website has been created to support the programme at www.mightygiants.com, while new children-friendly products and packaging have been introduced featuring Nickelodeon characters.