Young Australians have a reputation for being fit and enjoying a sporty, outdoorsy lifestyle, but research released Monday found they are stacking on more weight than any other age group.
The alarming findings of the Australian Diabetes, Obesity and Lifestyle Study have raised concerns that by putting on so much weight in their 20s and 30s, Australians are at more risk of developing diabetes in middle age.
"The trend for greater weight gain amongst people aged 25-34 is very concerning and suggests Australia still does not recognise the serious health risks associated with being overweight or obese," said study co-chief investigator Jonathan Shaw.
"The health and well-being of a whole generation of young Australians is being compromised by a lifestyle rich in energy-dense foods and low on physical activity."
The study, which has tracked 11,000 respondents across the nation over 12 years, found that for all ages the average weight gain was 2.6 kilograms (5.7 pounds).
But those aged 25-34 when they first interviewed for the study in 1999 or 2000, had stacked on the most since then, with an average 6.7 kilogram gain.
"We've seen that over 12 years people are, on average, continuing to put on weight," said Shaw, who called for tough decisions from governments to improve health outcomes.
"On average 5.3 centimetres (2.1 inches) extra waist circumference across the whole population but particularly so in younger adults."
Waistlines for the original 25-34 group stretched 6.6 centimetres over the period.
The study revealed major discrepancies between participant's perceptions about how long they spent sitting and the actual amount of time in which they were sedentary.
Participants self-reported that they spent an average of 200 minutes a day sitting but measurement devices worn by them recorded an average 500 minutes a day spent sitting down.
The study is the largest Australian longitudinal population-based study of its kind and has tracked the 11,000 respondents for more than a decade to determine how many of the participants develop diabetes, obesity, kidney and heart disease.
The latest data, taken in 2011-12, found that living in the most socially disadvantaged areas doubled the risk of developing diabetes while the prevalence of depression was much higher in obese people.