Children do not understand that ads are designed to persuade them to buy a product until around age 8. 'Even when they understand it, they don't necessarily use that fact to assess the messages in an ad.'

The new report by the National Academy of Sciences is considered the most authoritative review to date of how junk food ads and marketing threaten the health of young children.

To help reverse that influence, the report recommends that food companies stop targeting children with "spokescharacters," such as SpongeBob SquarePants and Barbie dolls, to promote foods high in calories and low in nutrients.

Some food companies already have begun shifting their children's advertising to healthier fare. But the new report's call for government to consider additional regulation incensed advertising groups, which believe companies should be free to market to children so long as their ads are not misleading.

The study's authors -- including experts in psychology, nutrition, law and education -- said the standards for advertising must be higher for children.

Rising Childhood Obesity Rate

Studies have not proven conclusively that junk food marketing leads to childhood obesity, the authors conceded. The evidence does show that advertising causes children to eat more high-calorie foods, and that television viewing in general is linked with weight problems among children and teens.

"Current marketing practices are putting the diet-related health of children and youth in this country at great risk," said co-author Mary Story, a professor of epidemiology at the University of Minnesota's School of Public Health.

But if companies agree to market healthier foods, she said, "the food industry and food marketing can play a vital role in turning this around."

The industry's marketing tactics have drawn more attention as public health experts raised the alarm about America's rising childhood obesity rate. A Tribune special report in August detailed more than a decade of marketing efforts at Northfield-based Kraft Inc. that targeted children with some of Kraft's most fattening foods.

Kraft has changed course in the last year, focusing on marketing its healthier offerings to children under age 12. Yet the company still uses some techniques that the National Academy of Sciences panel criticized, including Internet "advergames" that promote brands such as Oreo cookies.

The new report won praise from some industry groups and public health advocates alike. Kraft spokesman Mark Berlind called the paper "an important milestone." Marion Nestle, a nutrition professor at New York University and frequent food industry critic, said the report is "a great compendium from a reliable source."

Violate Free Speech?

But the recommendations were ominous to Wally Snyder, CEO of the American Advertising Federation, a lobbying group whose 130 corporate members include food and beverage giants such as Kraft and PepsiCo. The group also represents numerous media companies, including Tribune Co.

Snyder pointed out that although the authors called for companies to focus their ads on healthier products, the report offered no clear definition of which products would qualify. Also, attempts by government to restrict how companies advertise could violate free-speech protections, he said.

"The proposition we have lived by in this country is that you can give information as long as it's truthful to consumers," Snyder said.

"I think companies are going to follow the course of action that's best for them, and I don't think the government needs to worry about that."

In recent years the US Supreme Court has made it more difficult for government to restrict what advertisers can do, according to the report, whose authors include Yale Law School professor Robert C. Post.

Yet the courts long have drawn a distinction between adults and children. The authors wrote, "Advertisements that are acceptable if addressed to an adult, might be deceptive, unfair, or misleading when directed to a child."

Children Perceive Ads Differently

Food ads on broadcast television may be easiest for Congress to regulate because the Supreme Court has held that the airways are a public resource. The Children's Television Act of 1990 requires broadcasters to limit all advertising in children's TV programming to no more than 10.5 minutes an hour on weekends and up to 12 minutes an hour on weekdays.

The status of food ads placed elsewhere, such as cable TV or the Internet, could hinge on whether children can understand the purpose of such messages. The new report suggests children perceive ads and other marketing techniques far differently than adults do.

Even pre-schoolers have some ability to distinguish television ads from other programs, said co-author Aimee Dorr, dean of the graduate school of education and information studies at the University of California at Los Angeles. But they do not understand that ads are designed to persuade them to buy a product until around age 8.

"Even when they understand it, they don't necessarily use that fact to assess the messages in an ad," Dorr said.

Several panel members said that before they embarked on the study last year, they had not fully grasped the extent of the industry's marketing and research aimed at children.

Opportunity to Change Children's Diets

TV ads are merely the biggest element of a broader effort that extends far beyond TV, the authors said. Food companies also pay for product placement on well-liked shows, beneficial shelf placement in grocery stores, special promotion events such as cookie-stacking contests and, recently, ads sent via mobile phones.

"One could say that food marketing is ubiquitous to children," said co-author Ellen Wartella, provost of the University of California at Riverside, who also is on Kraft's nutrition and wellness advisory committee.

The report describes a version of "viral marketing," in which a company "may hire young actors who sign a confidentiality agreement and then interact with unsuspecting consumers in a popular or public gathering spot."

It is unclear whether food companies widely use the technique, which is intended to build "buzz" around a product. At the least, such methods show how calibrated the industry's efforts can be, experts said.

"The industry is so much farther ahead in [its] understanding than anything going on in a university," said study co-author Lloyd Kolbe, a professor of applied health science at Indiana University.

That expertise could be an opportunity to change children's diets, the panel said.

'Works Brilliantly'

To increase the appeal of healthier foods, the board called on the food industry to share its knowledge about which marketing techniques work on younger audiences. Companies have been reluctant to share that knowledge, which they consider proprietary. But the study's authors said some companies indicated they may be open to sharing some of their marketing research in a database.

"We want them to use their tremendous creativity to market healthier foods," said panel member Sandra Calvert, director of the Children's Digital Media Center at Georgetown University. "They have two years to do it or else we have asked Congress to take action."

US Sen. Tom Harkin (D-Iowa) requested the report last year. Harkin, who has introduced legislation directing the Federal Trade Commission to closely monitor food marketing to children, said Tuesday he was not surprised by the findings.

"The industry doesn't spend $11 billion a year marketing junk food to kids in order to waste money," Harkin said. "They spend $11 billion a year marketing junk food to kids because it works brilliantly."

By Jeremy Manier and Delroy Alexander