If you think SpongeBob puts junk in your kids' heads, then you need to pay closer attention to the commercials.

A new study finds that about one-fifth of commercials kids are likely to see on late-afternoon and Saturday morning television are food-related, and of those, 70 percent advertise fast-food restaurants, sugary food, chips, crackers and sugar-added beverages.

Fruits, vegetables, and juices were advertised in only 1.7 percent of the commercials. Only one nutrition-related public service announcement was found for every 63 food ads.

Highly processed foods are known to contribute to poor diets, obesity and a soaring diabetes problem in the United States.

The study, announced Wednesday, examined 5,724 commercials on 12 networks, including all the usual suspects your kids watch.

When compared to television for a general audience, children's networks in this study exposed young viewers to 76 percent more food commercials per hour than did the other networks, with the Saturday morning 7-10 a.m. time slot being more saturated with food commercials, the researchers explained in a statement.

You can assume your kids see a food commercial every 8 minutes, sandwiched presumably between Bendaroos and, oddly, the Sham Wow guy.

It doesn't get any better as the little tykes grow up. Eighty percent of MTV food commercials were for fast food restaurants, sugar-added beverages, and sweets.

The study, detailed in the November/December issue of the Journal of Nutrition Education and Behavior, covered both English and Spanish-language networks and programs.

"Study after study has documented the adverse health effects of food advertising targeting children and adolescents," write Robert A. Bell and colleagues at the University of California, Davis. "Greater awareness of the potential influence of industry may immunize young people from food advertising's deleterious effects."