If you want a kid to choose an apple over a cookie as a snack, slap a picture of a cartoon character on the apple.

It really works, at least pretty often, according to a new study just published in the Archives of Pediatric and Adolescent Medicine. The researchers found that 37 percent of children chose an apple over a cookie when the apple was branded with a sticker of Sesame Street idol Elmo. Only 9 percent picked the apple when it wasn’t Elmo branded.

The researchers note that it’s like fighting fire with fire. Sugary products for children are often decorated with cheerful pictures of cartoon characters.