Two-thirds of Australia's adult population are overweight or obese, a key study has found, with rates continuing to climb despite a drop in smoking and drinking.
The Australian Bureau of Statistics (ABS) said people were continuing to pile on the kilos despite other findings indicating a switch to healthier habits.
The study found 63.4 per cent of the population are now classified as overweight or obese - an increase of more than two percentage points from four years ago.
"The proportion of overweight adult Australians has increased by more than two percentage points, meaning that nearly two-thirds of the population are now classified as overweight or obese," said ABS statistician Paul Jelfs.
The figure compares to 56.3 per cent in 1995 and 61.2 per cent in 2007-08.
Jelfs said the 2011-12 Australian Health Survey of 33,500 people found that 70.3 per cent of men and 56.2 per cent of women were losing what he called the "battle of the bulge", with one-quarter of children also classed as overweight.
The survey, described by ABS as the "largest check-up on the nation's health ever undertaken", calculated whether or not people were too heavy using the Body Mass Index system.
The formula for calculating a person's BMI is weight in kilograms divided by height in metres squared. The resulting number then tells researchers whether the individual is overweight for their height.
Australia is ranked fifth among advanced nations in terms of obesity after the United States, Mexico, New Zealand and Chile, according to the OECD.
Despite the worrying trend for increasing obesity, Jelfs said the survey did throw up some heartening findings.
The number of daily smokers fell almost three percentage points in the past four years, to 16.3 per cent, or 2.8 million smokers, out of a population of nearly 23 million.
The rate was 18.9 per cent in the 2007-08 survey and 22.4 per cent back in 2001.
Australia won a High Court battle with major cigarette firms this year to become the first country in the world to mandate plain packaging for tobacco products in a bid to curb smoking and related health costs.
It is also trying to reduce binge-drinking through a combination of shock advertising campaigns and taxation, with a government report due to be released in coming weeks on the potential introduction of a floor price on alcohol.
Jelfs said the number of adults consuming more than two standard drinks a day had dropped 1.4 percentage points in four years, but was still a relatively high 19.5 per cent.
Australian guidelines recommend having no more than two standard drinks a day to reduce the long-time risk of harm from alcohol-related disease or injury.