Outside the classroom the former Devonport author was emotional.

Eating disorders still have an ugly stigma attached and the hardest thing is to ask for help.

Ms Hanson had been speaking at a Fit Club health and wellbeing forum at Wynyard High School.

"It was years after I went to America on a tennis scholarship and developed an eating disorder myself that I found out about how an eating disorder took the life of a woman I knew in Grade 11," Ms Hanson told the students.

"When I had my ED (eating disorder) I lost the plot. I didn't have an ounce of energy left to play tennis but we were a group of tennis girls and we were pretty much all the same - obsessed with food, diet and calories."

The more she talks about body image issues, the more she discovers those suffering in silence.

Three articulate Grade 8 girls told Ms Hansen and Fit Club dietitian Gaye Rutherford of the pressures kids feel every day just getting ready for school.

"When it was primary school you had a shower and ran fingers through your hair a bit, but at high school it's like you have to live up to some standard," Olivia Kittle said.

"It's weird ... people can pick out the tiniest thing wrong with your appearance," Samantha Flight said.

Ms Rutherford gave a power point presentation that talked about the adverse effect of dieting for image and the unreal ideal of cover girls and models.

She ran a Dove advertisement of a normal looking blonde woman transformed with computer enhancement to the unobtainable air brushed cover model.

It had an audible impact on the students as it was shown.

"That picture was changed so much you wouldn't recognise her at all," Ally Hubbard said.

The three students agreed they looked at magazines and wanted to be the same as the women featured.

"It's just fake but we look at them and think we should be like that," Ally said.

Ms Rutherford's presentation also highlighted how commenting on a person's weight was the last acceptable form of discrimination in society.

"We still make comments like `look at that wide backside she'd need two chairs to sit on'," she said.

"What if the person heard you, what if a few months ago she weighed a lot more and had been working hard to lose weight?"