New Australian research predicts that children who are fat can expect to die four years earlier than their thinner peers.
The research by scientists at the University of Western Australia has found that Australians with a body mass index over 30, will live for between 3.5 and 4.5 years less.
They say the obesity epidemic will attribute to so many deaths that the average life expectancy of the entire Australian population will decrease by two years.
At present the life expectancies for Australians are 80 years for men and 84 for women.
Even the overweight with a BMI between 25 and 30, have a six-month shorter than average life expectancy.
Professor Mike Daube, director of the Perth-based Public Health Advocacy Institute which commissioned the report, says the situation was "a public catastrophe" which calls for tough action.
Professor Daube says governments must be willing to take on the vested interests of groups such as the junk food industry.
Daube says Australians live in a country with one of the longest life expectancies on earth and should be increasing it, not reducing it.
It is estimated that as many as 9,500 Australian premature deaths are because of excess weight and currently almost a quarter of Australian children and adolescents are estimated to be overweight, with one in four who are obese.
Experts believe that if the obesity trends continue, a generation of men now aged 20 can expect to lose 1.72 years from their life expectancy, while women will average 2.17 years less.
Professor Daube has praised the Victorian Government for leading the way on tobacco controls and seatbelt laws and he hopes state and federal governments will work together for long-term answers to a new generational epidemic.
Pediatricians say the findings support international research and emphasise the need for cultural change.