Branding apples with cartoon characters like Elmo could help school children to make healthier snack choices, a U.S. study finds.

In an experiment, researchers offered elementary school students apples or cookies at lunch that were branded with a cartoon sticker, such as the Sesame Street character Elmo, no sticker, or a sticker of an unknown character.

Mascots and characters can be used to build excitement around healthy foods. (Mike Derer/Associated Press)

The Elmo sticker led children to nearly double their apple choices, Brian Wansick, a marketing professor at Cornell University and his co-authors said in a letter published in this week's issue of the Archives of Pediatrics and Adolescent Medicine.

"We tend to associate mascots and characters with junk food, but they can also be used to build excitement around healthy foods," Wansick said in a release.

"This is a powerful lesson for fast food companies, food activists and people involved in school food service."

The study looked at 208 children aged eight to 11 in New York over five consecutive days during lunchtime.

After choosing their lunch, each child was offered an apple, a cookie, or both.

On some days, the snacks were offered without branding and on other days, either the cookie or apple came with an Elmo sticker.

There was no effect of the Elmo icon on cookie consumption, the researchers found.

"This study suggests that the use of branding or appealing branded characters may be benefit heathier foods more than indulgent, more highly processed foods," the study's authors concluded.

"Just as attractive names have been shown to increase the selection of healthier foods in school lunchrooms, brands and cartoon characters can do the same with preliterate children."

Last week, Canadian researchers reported that children are far more likely to pick a healthier fast-food meal when promotional toys are offered with those foods instead of the usual burgers, fries and a pop.