Almost one million Australians have become obese over the past three years.
Australia has "completely failed" to address its obesity crisis, with migrant and Indigenous communities particularly "hard hit".
A report released by the Collective for Action on Obesity on Wednesday found around 900,000 additional Australians had become obese over the last three years.
The report said at a government level, "no lasting comprehensive action [has] flowed from previous strategies and, as a result, Australia has gone backwards at an alarming rate".
It found the number of children living with obesity has increased by 60 per cent since 2011-12 from 249,000 to 396,400, or 24,500 additional children each year.
Nicole Turner of the Collective for Action on Obesity said the recent spike in the number of obese Australians was "shocking".
"It's very alarming, especially [when you consider] the cost to the government and productivity," she told SBS News.
The report said the cost of obesity in 2017-18 was $11.8 billion, made up of $5.4 billion in direct health costs and $6.4 billion in indirect costs.
Migrant groups and Indigenous Australians
Ms Turner said many migrant communities in Australia were "missing out" on obesity prevention efforts.
"Programs have to be culturally adapted to a community. You can't just run a mainstream program and put it in any community," she said.
Ms Turner encouraged the government to work closer with migrant groups to reassess obesity prevention.
Specifically, Ms Turner said programs could promote "access to cultural foods" and make these as available as "very quick takeaway cheap food".
Wednesday's report also said obesity contributes to 16 per cent of the health gap for Indigenous Australians.
As such, Ms Turner said addressing obesity in Indigenous communities will dramatically improve other health outcomes
"An [Indigenous] community with high obesity has higher mortality and mobility rates and very high chronic disease rates," she said.
"Then there's mental health issues ... If you're sick it affects your whole well-being, not just your body".
Looking forward, the report found at current rates, more than 40 per cent of the Australian adult population will be living with obesity within a decade.
Ms Turner said this numbers showed "there needs to be lots of changes around how the money is spent and where the money is going to".
Last October at a Council of Australian Governments Health Council meeting, ministers agreed that a new National Obesity Strategy would be developed.
A National Obesity Summit was then held last month which promoted "fresh thinking in terms of our approach to obesity prevention and control".
"It is obvious that the challenge of obesity is getting bigger and clearly some of the old approaches just aren’t working," Minister for Regional Services and Sport Bridget McKenzie said at the event.