Fast food companies are dominating television programming for toddlers, suggests a study published in the October issue of the journal Pediatrics.

Susan Connor, a research manager for Cleveland's Rainbow Babies & Children's Hospital, said she was inspired to study the effects of advertising on toddlers when her three-year-old toddler began humming the McDonald's jingle.

"He had absorbed that from watching TV," said Connor. "It would be a marketer's dream to know they were that successful."

The study found that messages for high-fat, high-sugar foods abounded on the child-targeted Nickelodeon specialty channel, the Disney Channel and on certain child-focused shows such as Sesame Street on the Public Broadcasting Service.

Both Disney and PBS, which promote their policy of ad-free programming, show corporate sponsor messages. Connor's study found that high-fat foods account for 82 per cent of sponsor messages on PBS preschool programming and 36 per cent on Disney's shows for toddlers.

"The majority of child-oriented food advertisements viewed seemed to take a branding approach, focusing on creating lifelong customers rather than generating immediate sales," the study noted. Connor also suggested that the advertisements adopted similar approaches, linking food with fun and happiness.

Last week, the U.S. Federal Communications Commission announced plans to examine ties between advertisements, viewing habits and the rise of childhood obesity.

The commission cited reports indicating that the average child watches two to four hours of television per day and views about 40,000 TV ads every year. The majority of these ads are for cereal, candy, toys and fast food.

Diane Levin, a professor of education at Wheelock College and a co-founder of the Campaign for a Commercial-Free Childhood, said Disney and PBS had violated viewers' trust.

"PBS has a special responsibility," Levin told the Associated Press. Levin, who was not involved in the study, noted that PBS has had to seek out new revenue because of unstable federal funding.

PBS spokeswoman Lea Sloan defended the sponsors' messages, saying that the messages don't run longer than two minutes, 17 seconds per hour. PBS also doesn't allow price information, product comparisons, or superlative claims, she said.

"The content of these messages is either in support of public television or around learning, education and social development," Sloan told AP. "Licensed characters or mascots often reinforce a positive educational message and their appearance is limited to five seconds."

Meanwhile a Nickelodeon spokesman said the channel has reduced food ads by 20 per cent during children's programming. 

A Disney representative said sponsor messages are aired only when they are tied to a "pro-social" message.

With files from the Associated Press