Public health campaigns targeting people with obesity are often useless and could be doing more harm than good, according to leading international experts who say the Federal Government needs to do much more to tackle the chronic disease.

Key points: Calls for the Federal Government to overhaul its approach to preventing obesity

Calls for the Federal Government to overhaul its approach to preventing obesity Health experts say public campaigns targeting obesity are effectively useless

Health experts say public campaigns targeting obesity are effectively useless Academics warn children with weight stigmas are more likely to put on extra weight

The experts warn that obesity is the most serious chronic disease of modern times but the approaches to date have failed.

"They've looked at obesity as being really just about either eating or just about exercise, and if obesity was really that simple I wouldn't have a job," said Dr Fatima Cody Stanford an obesity specialist at Massachusetts General Hospital.

The failure of obesity ads sits in contrast to the power of other public health campaigns.

The "Slip, Slop, Slap" ads are linked to a decrease in the prevalence of melanoma over the last three decades, while Australia's graphic "Every cigarette causes you damage" campaign was also linked to a significant reduction in smoking among Australian adults.

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"When we target just one thing of maybe thousands of things, the likelihood we'll have a shift in status is minimal in best. That's why we really haven't seen any major shifts with many of these campaigns that have had a single focus," Dr Stanford said.

She said the campaigns were not only ineffective, they could also be harmful.

"This idea of shame and blame — it leads to worse outcomes," Dr Stanford said.

"The toughest critics of people who have obesity are people who have obesity, because they've been taught their entire life, as they've struggled their entire life, that they're not worthy of anything positive in their life.

"They've been told they're just not valuable, and that's reflected in their whole being. So we have to start from a place of love and respect."

Experts around the world are split on the best way to tackle obesity. ( ABC News: Emma Machan )

Singapore trials 'blame and shame'

Far from love and respect was a controversial approach to reducing childhood obesity rates in Singapore that started in the early 1990s.

The overall percentage of overweight students decreased by 2 per cent over the lifetime of its "Trim and Fit" program.

The World Health Organisation (WHO) has also labelled it as one of the most efficient and effective ways of improving the lives of young people.

But they also came at a personal cost.

The program singled out overweight and obese children for extra exercise sessions.

Some students reported being forced to skip recess and exercise in front of the canteen, as all of their friends watched.

A study of more than 4,400 schoolgirls in 2005 linked the program to an increase in eating disorders.

While that link was rejected by the Singaporean Ministry of Education, concerns about the stigma faced by students led to the program being reviewed and ultimately replaced in 2007.

"I'm completely against any campaigns that are stigmatising," Dr Stanford said.

"There's no benefit, they're harmful. So let's not do it."

Doctors want people to feel good about their bodies

Assistant Professor Tracy Richmond from Harvard Medical School investigated the impact of body positivity on young people.

She said children who saw themselves as being "just about right" had fewer depressive symptoms and were less likely to develop eating disorders.

"What we ended up hypothesising, and we're interested in examining more, is feeling good about your body is healthy in general," Dr Richmond said.

"It allows kids to make better choices in their behaviours, and therefore go on to gain less weight."

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But the chief executive of the Public Health Association of Australia, Terry Slevin, said not all campaigns were damaging.

He cited the "LiveLighter" campaign in Western Australia, which has been running since 2012 and is a combination of advertising campaigns and online resources.

"LiveLighter and similar campaigns can be helpful in terms of setting the agenda and emphasising the importance of maintaining a healthy body weight and encouraging those who are overweight to take action," Mr Slevin said.

He Slevin said the campaign had taken particular care not to contribute to any weight stigma.

"Bearing in mind we are the fattest generation Australia has ever produced, unless we tackle that, with a range of things, and sometimes people are going to feel uncomfortable, than that trend is only going to get worse," Mr Slevin said.

"We don't want to not tackle the problem for fear of offending a small number of people."

Australia's obesity rate continues to grow

Just over 30 per cent of Australians have obesity, costing the country about $60 billion dollars a year.

But just 2 per cent of this year's federal health budget has been allocated towards preventative health.

It is something health advocates like Mr Slevin have been consistently campaigning to change.

Australian Institute of Health and Welfare figures showed that in 2015, almost 40 per cent of the nation's disease burden, which is the impact of a health problem as measured by things like cost, or death, was preventable.

Mr Slevin said the Government should be allocating at least 5 per cent of its health budget to preventative health.

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There are also calls for tax on sugar sweetened beverages, as part of a broad range of strategies to target obesity, despite both industry and government push back.

"It is not a panacea for all obesity, but empty energy calories, empty energy input is simply not part of a good healthy lifestyle," AMA President Tony Bartone said.

"Also that levy can feed in to other important preventative strategies, and can be used to fund those initiatives appropriately — it's understanding it is only but one part of a complex solution."

But Dr Stanford said a sugar tax was effectively useless.

"People might buy less, [but] if they still want sugar — they will have sugar."

Calls for cheaper fruits and vegetables

Dr Stanford said with many factors causing obesity, it was time for governments around the world to start taking a different approach to treating the disease.

She said the first thing governments needed to do was make sure fresh fruit and vegetables were available and cheaper.

The Government needs to target obesity from every angle as it is a complex disease. ( ABC News: Emma Machan )

"You need to target them with education about diet, exercise, sleep, about medication they're on, you need to target them by maybe offering discounts or incentives to go to the gym, make sure they have high-quality, minimally processed foods.

"Every angle. It's hard - this is hard work. And this is why governments don't want to do it.

"This is harder than anything they've ever had to do."

Federal Health Minister Greg Hunt this week confirmed the government would establish a new national preventive strategy.

"This is a comprehensive approach," he said.

"The critical thing is to explain that health is not about weight... it's about ensuring people have the right amount of physical activity and a balanced diet."