EUGENE, Ore. - Anyone with a teenager knows telling them what to do doesn't mean they'll do it.

Turns out this concept is also true when it comes to eating disorders.

Scientists at the Oregon Research Institute are helping teens improve their body image and preventing eating disorders by letting them figure it out themselves.

Kelsey Hertel is a happy, healthy Sheldon High School student.

Judging by her trim physique, you probably wouldn't guess that she hasn't always loved the way her body looks.

"I knew that my self image was iffy just like all girls are," Hertel said.

Many young women have body image issues. Ask anyone on a high school or college campus and they'll tell you about the constant media assault to be thin.

"There's still pressure to be thin, small, tan, blond," said University of Oregon student Arielle Kane said.

For about 8 percent of young women, that pressure turns into dangerous eating disorders.

But researchers said telling young people what to do isn't preventing eating disorders.

"Just educating people don't seem to change behavior so we decided to try something completely different," said Eric Stice of ORI.

Stice developed a program published in this month's Journal of Clinical Psychology.

It's based on the persuasion principal: If you're asked to argue for something, you're more likely to believe it.

"We do look at the images, and they tell us how deceptive they are, how it's rare to have bodies like that, but it's important for it to come from their mouths, not ours," Stice said.

The girls dissect the thin ideal images they're bombarded with and form their own opinions.

Kelsey Hertel, research participant, said she learned a lot in the program.

"What are we supposed to think and what do we think and then we finally came to the conclusion of why are we wasting our lives looking at ourselves as less of a person," she said.

And changed opinions lead to changed behaviors. After three years the girls in the study showed a 61 percent decrease in eating disorders.

For Hertel, the experience left her feeling better about her body and herself.

"I am way cooler of a person than the culture tells me I am," she said.

Some 450 local teens are currently in this program at area high schools.