Australasia has world's fastest obesity rate

The largest increase in adult obesity in the world occurred in Australasia in the past 30 years rising by more than 80 percent, according to a new study.

Tonga, where 60 percent of the population is obese, is the world's fattest nation.

The Institute for Health Metrics and Evaluation at the University of Washington revealed that 2.1 billion peoplenearly 30 percent of the world's populationare either obese or overweight.

Overweight is defined as having a Body Mass Index (BMI), or weight-to-height ratio, greater than or equal to 25, while obesity is defined as having a BMI equal to or greater than 30.

In 1980 Australia ranked the 63rd in the world for obesity, but by last year this rating soared to 25th.

"Not only is obesity increasing, but no national success stories have been reported in the past 33 years. Urgent global action and leadership is needed to help countries to more effectively intervene," the report said.

In Australia the growth in obesity was 13 percent -- the same growth rate as the United States.

The study showed the rate of growth in obesity levels in Australia is the second highest level in the world.

Only in New Zealand, Saudi Arabia and Bahrain, where the growth rate in obesity was 14 percent since 1980, were rising higher.