The latest food policy index report found variations in plans across state and federal governments was hindering efforts to improve the health of Australians.
While NSW leads the way in developing health plans, Obesity Policy Coalition executive manager Jane Martin said strategies needed to be put in place across Australia.
Last year, the Council of Australian Governments agreed to develop a national obesity strategy.
"Tasmania is certainly falling behind there ... so I think looking to other states and applying those same policies would certainly be an improvement," Ms Martin told AAP.
"You may not get a decrease in overweight and obesity in time, but you'll potentially see a slowing down.
"Governments are starting to sit up and take notice of one of the biggest public health challenges of our time.
"Good policies exist, but they are not being implemented in a coordinated way."
Ms Martin said the biggest gap between states and territories exists with the different ways they market junk food to children.
"Children are flooded with junk food ads for unhealthy food on their walks to school, when they're waiting for the train and when they're watching sport on TV," she said.
"It's time that all levels of government take the steps required to protect our children from this relentless push to consume junk food."
NSW has been monitoring food served in schools, while the ACT has removed junk food advertising from Canberra's bus network.