Almost two in three Australians are now overweight or obese, with Australians living outside major cities the most likely to have a body mass index (BMI) beyond the healthy range.
Australia is the fifth most overweight and obese among all OECD countries, with 11.2 million adults (63 per cent) and 1.2 million children (26 per cent) with a BMI 25 or higher.
Sydneysiders were among those least likely to be overweight or obese, according to the latest report from the Australian Institute of Health and Welfare (AIHW).
Northern Sydney had the lowest rate of overweight or obese adults in Australia (53 per cent), with Central and Eastern Sydney (57 per cent) and South-western Sydney (58 per cent) having the third and fourth lowest rates respectively.
Western Sydney (65 per cent) had the third-highest rate among metropolitan areas but only the 14th highest nationally, when regional areas were included.
Of the 10 Primary Health Networks (PHNs) with the highest rates of overweight or obese adults, nine were from regional areas. The only metropolitan area in the top 10 was the Nepean Blue Mountains area (66.9 per cent) which tied for ninth.
The stark difference between regional and metropolitan Australia also holds true for children. More than one-third (36 per cent) of children two to 17 in outer regional areas were overweight or obese compared to 22 per cent in inner regional areas and 25 per cent in major cities.
Released on Friday, the report provides an overview of several reports generated using 2014-2015 ABS data from each of the 31 PHNs areas in Australia.
"What we're aiming to do is bring together a range of data so that we have a comprehensive picture of obesity in one place," said Lynelle Moon, head of the health group at the institute. "It confirms what we've known; that obesity is a major public health issue and that it's become more common in recent decades."
Eastern Melbourne recorded the greatest increase in rates of overweight or obese adults, jumping from 58 per cent to 66 per cent since 2011-2012. Western NSW recorded the biggest drop, with overweight and obesity rates declining from 78 per cent to 71 per cent.
In a small number of age groups, there are signs of the situation improving.
Obesity rates had plateaued among 10 to 17-year-olds, but the rates of overweight adolescents was still on the rise, Dr Moon said.
Low socioeconomic status was associated with high BMIs. The most disadvantaged children were 1.5 times more likely to be overweight or obese compared to children from the most affluent areas.
The report also showed that the number of weightloss surgery hospitalisations has more than doubled in the past decade.
Obesity cost the economy an estimated $8.6 billion in 2011-12 and is predicted to eat up another $87.7 billion in the next 10 years, according to an analysis by PwC.
Highest rates of overweight and obese adults
Country South Australia
Western New South Wales
Darling Downs & West Moreton (QLD)
South-eastern New South Wales
Lowest rates of overweight and obese adults
Northern Sydney (NSW)
Perth North (WA)
Central & Eastern Sydney (NSW)
South-western Sydney (NSW)
Brisbane North (QLD)