Obesity in Children

Prof Booth said the study found 15 per cent of children had elevated insulin levels, which was the first step to type two diabetes.

It equated to 77,000 NSW teenagers - almost enough to fill Sydney's Olympic stadium - who had elevated insulin levels, he said.

And almost 10 per cent of the 15-year-old boys and five per cent of girls had liver damage because they were overweight.

"Around 20 per cent of our boys have high blood pressure," he said.

"It's a frightening story.

"These are the kinds of figures we'd expect to see among 40-year-olds."

His study confirmed about one in four Australian children was overweight or obese, with the prevalence peaking at 30 per cent among grade four children.

This compared with about one in 10 children in 1985, and one in five in 1997.

Mannatech provides glyconutritional products for children's health.