The limits placed on marketers' licensed use of characters from Cartoon series will be on products that restrict calories, saturated fat, trans fat and sugar, among other ingredients.
All three networks made the similar announcements last week. They want to ward off lawsuits and government pressure, charging that they are contributing to widespread childhood obesity.
There has been some concern that such curbs might hurt ad revenues at the networks, but Nickelodeon has dismissed the idea. The net said it has had success attracting dollars from companies looking to market healthy foods. While perhaps unrelated, Time Warner has said Cartoon Network recently completed a poor upfront.
Cartoon's new restrictions will take effect Jan. 1.
The network also said it's collaborating with nutritionists to develop healthy-living messages that it can weave within its programming.
Of the three networks, Nickelodeon arguably has the most recognizable characters, such as SpongeBob and Dora the Explorer, that are subject to the new policies.
There are, however, exceptions to the policies at all three nets. Discovery will allow licensing on what it calls "special occasion sweets such as birthday cakes" and events related to holidays.