New research released in American Samoa shows that over 80 percent of girls and around 70 percent of boys aged between 15 and 18 are either obese or overweight.
The study also shows that around half the children between 6 and 11 years old are overweight.
Professor Stephen McGarvey of Brown University in the United States interviewed 600 children in 2002 as part of the research.
He believes the increase in obesity is a result of a move away from traditional foods and an increase in the consumption of sodas and pre-packaged foods.
Earlier today Professor McGarvey presented his research to a number of doctors in American Samoa who he says were grateful for his research.
"They are concerned, they were alarmed, they recognise these things have been going on and then we talked a lot about prevention programmes, both the early prevention of overweight in children and young adults, and also prevention of the complications of obesity in adults like hypertension and controlling of diabetes and things like that."
Professor Stephen McGarvey of Brown University.