Some children like to read Dr. Seuss books, others prefer the Berenstein Bears. But 6-year-old Ishai Melamed likes to read food labels.
And not only does he read the labels, he understands them. Melamed is one of about a dozen kindergartners who participate in an Ad Busters class, an after-school program at Public School 321 in Brooklyn, New York.
Once a week, journalist and mother Susan Gregory Thomas collects her charges from school, and they head to the Key Foods supermarket three blocks away.
Thomas wants to teach these children to be critical of what they eat, and of how food is marketed to them.
"One child in my class, James, after we took a field trip to a local grocery store, he sort of gravitated immediately for the 'Dora' soup," Thomas told "Nightline," referring to the popular cartoon character.
"The next time he went into the store with his mother he said, 'Let's read that label, Mom. We're not sure if it's gonna be too much saturated fat in it for us,'" she said.
By profession, Thomas is an investigative journalist. In her latest book, "Buy, Buy Baby," she examined how products are sold to kids and their parents. Thomas said putting animated characters, like Dora the Explorer and Shrek, on everything from sugary cereals to macaroni and cheese has made it more difficult for parents at the supermarket.
"Well, I think oftentimes ... children are going to be gravitating to the licensed products," she said. "You know, they're gonna want the 'Dora' soup over the organic chicken stew."
And, said Thomas, the problem is evolving. Another difference, she said, is that older symbols like Tony the Tiger were confined to cereal. Modern characters sell everything, and they're also perceived as educational models..
"One of the things that is really difficult for children," said Thomas, "especially under the age of 8, is understanding the difference between advertising and reality. They just don't understand the persuasive tactics."
"They fall for it every time, and they don't understand that they are being led down a garden path in a deliberate way," she said.
The idea for the Ad Busters class came from conversations Thomas had with her own child, who's nicknamed Zuzu. She's 6 years old and a very discerning member of the class.
"Whenever we went into a store and saw Dora or Clifford or sort of any of these guys on a product," said Thomas, "I began to ask her, 'I wonder why Dora is on that mac and cheese box? Why do you think so? And she would say, 'Well, I think it's because kids would like it.'"
But they are, after all, just 5 and 6 years old. They may have the best intentions, but as any parent knows, it takes a strong will -- and a guiding hand -- to keep them from gravitating to the characters they know and love.
Thomas' guiding hand seems to be working. "Is [saturated] fat good for your body?" she asked the group. "No," the kids replied in unison. "Why," she asked. "'Cause it could clog up your brain," answered one boy. "No, it can clog up your heart," she said.
OK, so they're not medical students, but they're learning to be more aware of what they eat, and how it's sold to them.
"You know what the companies call it?" said Thomas. "They call it pester power. You know what that means?"