In a step toward improving the diets of America's youngest consumers, 11 big food companies will stop advertising certain cereals, snacks and other items on children's TV unless they can lower the products' sugar, fat and calories. The voluntary move is aimed at heading off a government crackdown prompted partly by an increase in childhood obesity (abnormally high weight).

Affected products include Trix, Cap'n Crunch, Foot Loops and Apple Jacks cereal, as well as Pop-Tarts and Bubblicious gum. If they can't change the ingredients to meet nutrition guidelines, food makers will replace ads for so-called junk foods with spots for healthier alternatives. 'We want to help families make good choices,' said an executive at General Mills, a major cereal brand. Another company, McDonald's, said its national kids' ads will feature only balanced meals of 600 calories or less.

Advertisers spend an estimated $900 million each year to influence children under 12 watching Nickelodeon, ABC Family, the Disney Channel, Cartoon Network and other channels. The voluntary limits exclude ads on 'family entertainment,' such as American Idol or the Animal Planet and National Geographic cable networks.

Food executive says: 'Food advertisers can and should be part of the solution, and this is an important step forward by our industry." -- David Mackay, president and chief executive officer of Kellogg Company.

Critic says: 'This is great public relations for the companies, but it doesn't go nearly far enough. It is going to be impossible to monitor if the companies are actually doing what they say.' -- Susan Linn, co-founder of Campaign for a Commercial-Free Childhood, a parents' group in Boston

Congressman says: 'I would like the media industries to come forward with their own set of voluntary commitments. Children's television is supposed to be an oasis for kids in the vast wasteland of television. Food marketers setting standards is half the battle, but unless the media companies also set standards, junk-food ads will keep popping up to pollute the oasis." -- Rep. Edward Markey, D-Mass., chairman of House telecommunications subcommittee