When it comes to healthful eating, teenagers follow their stomachs and not their heads, a nutritionist says.

Johanna Dwyer, director of the nutrition center at Tufts University, says more than half the kids surveyed in a 1989 Harris poll said they thought nutrition was important.On the day the survey was conducted, 25 percent of the teenage boys surveyed had eaten a hamburger, said Dwyer. Among the younger boys, pizza was the most popular food that day, she said.