Being physically active may not offer protection against type 2 diabetes if you are already overweight, new research shows.
The research -- to be presented at the Sax Institute's 45 and Up Study annual meeting in Sydney on Tuesday -- found that people who were obese, but were highly active and spent little time sitting still, had five times the risk of developing type 2 diabetes compared to people who were of normal weight
"The findings of our study are clear; if you want to avoid developing type 2 diabetes, being physically active is not enough if you are also overweight or obese," said researcher Binh Nguyen in a statement.
Nguyen conducted the study with colleagues from the University of Sydney's Prevention Research Collaboration.
"Those who were overweight and physically active had twice the risk of developing type 2 diabetes as people who were of normal weight, and less active. The odds of developing type 2 diabetes were even greater among people who were overweight or obese, and inactive," Ms Nguyen said.
Researchers investigated levels of physical activity and sitting time in 29,572 men and women enrolled in the 45 and Up Study, of whom 611 developed type 2 diabetes over the course of nearly three years.
· Diabetes is the fastest growing chronic condition in Australia
· Around 1.7 million Australians have diabetes
· More than 100,000 Australians have developed diabetes in the past year alone.
· Total annual cost impact of diabetes in Australia estimated at $14.6 billion
· Globally, diabetes accounted for 5.1 million deaths in 2013.
There has been considerable scientific debate about whether it is possible to be metabolically healthy while being overweight.
Scientific Director of the 45 and Up Study, Professor Emily Banks, said that the findings clearly demonstrated the value of Big Data research tools like the 45 and Up Study in addressing scientific controversies such as the "fat and fit" theory.
"The data tells us that being overweight or obese remains the major factor in developing type 2 diabetes and while being active is important, it's not a 'get out of jail free' card for people carrying excess weight. Maintaining a healthy weight by adopting healthy lifestyle behaviours, including a healthy diet, is the best way to prevent type 2 diabetes."
Sax Institute CEO Professor Sally Redman said that more than 650 researchers and policy makers from a wide range of organisations had used the 45 and Up Study in their work.
"Each year, the Study data gets richer and grows in value as a national research resource," she said.