The rising tsunami of diabetes in Sydney's western suburbs will overwhelm hospitals within 15 years and specialist factories will need to be built to perform amputations.

This is the warning of Western Sydney Local Health District chief executive Danny O'Connor, who said the bloating of the local population over the past 20 years has created a disaster in waiting that can only be averted by urgent preventative action.

About 300,000 of the one million people living in western Sydney are conservatively estimated to have diabetes or be at high risk, with more than half the population of Auburn, Blacktown, Holroyd, Parramatta and the Hills District overweight.

"It's about the survival of the species," Mr O'Connor said.

"If we continue to consume too many calories and convert to diabetes, we will have to build factories to cut off people's toes, feet and limbs and help them when they go blind.

"Let's have a conversation about taxing sugary drinks. Let's have a conversation about what's in school canteens. Let's have a conversation about the distribution and availability of fresh foods and fast foods, and urban design generally. It's a conversation we're at least 10 years too late in having."

Diabetes costs Australia at least $14.6 billion annually, a figure expected to blow out to $30 billion by 2025, and western Sydney has been identified as a hot spot.

The scale of the crisis facing the local health authority has forced it to move beyond its remit of dealing with acutely ill patients and into preventative health to stop its business model from failing.

It has formed a partnership with food chains, retailers, developers, councils and primary care groups with a goal to effect an average weight loss of four kilograms per person, bringing waistlines back to 1995 levels.

Obesity is one of the main causes of type two diabetes, which represents 85 to 90 per cent of diabetes in Australia. Unlike type one diabetes, it is preventable.

Blacktown endocrinologist Glen Maberly said even a small weight loss would prevent people from developing diabetes.

"We've been failing," Professor Maberly said.

"Diabetes is getting more prevalent and people are putting on more weight despite the fact there's been campaigns and people are becoming aware of it.

"That's really setting us up for the impact of this epidemic and we're at the beginning of it."

The practice

Dr Kean-Seng Lim with patient Fred Mark at his Mt Druitt practice. Photo: Louise Kennerley

Kean-Seng Lim had been practising in Mount Druitt for nearly 20 years when he noticed that his 130 kilogram scales were no longer sufficient to weigh many of his patients.

He upgraded to 160 kilogram scales, but soon these were maxing out as well, and he bought 200 kilogram scales. Again, he underestimated.

"We are now looking at scales that weigh up to 250 kilograms," Dr Lim said.

The increasing weight profile of the Mount Druitt population was one of the reasons Dr Lim completely redesigned his practice in 2012 to focus on chronic disease.

A dietitian, clinical pharmacist and exercise physiologist were employed to lend a team approach to individual patient management, and group sessions on exercise and diet - including a virtual supermarket tour - are run every Friday.

On Tuesday, Mavis Ball discussed with the team the management of her asthma, arthritis, cellulitis and how she could reduce weight, as she is a high diabetes risk.

Dietitian Dea Krismarietta suggested she eat more fish and take the skin off her chicken to reduce the amount of animal fat.

"That's the best bit," Ms Ball protested. "It's the tastiest."

Since the practice changed its approach it has recorded a significant improvement in its diabetic patients in terms of glucose control and weight loss.

Dr Lim said one of the difficulties was convincing patients they had a weight problem in the first place.

"They say, 'I'll look too skinny' or 'I'll look sick' or 'I'll get sick'," Dr Lim said.

"I have to say, 'One of the reasons you think you're normal is because everyone around you is overweight'. Our whole frame of perception has changed."

Fred Mark, 78, was diagnosed with diabetes in the early 1990s, when the disease was so rare. "I thought, 'I wonder if you can catch it,' because I didn't know anything about it," Mr Mark said. "Now I could write a book about it."

Although he has it under control, he said the years of insulin dependence had been draining.

"I wouldn't wish it on my worst enemy," Mr Mark said.

"You've got to change your whole lifestyle."

The best piece of advice he took from the practice was to buy a smaller plate.

"My daughter does the cooking and if I've got a big dinner plate she'll fill it and I'll eat it. So if she gives me a smaller dinner plate I'm not eating as much."

Preventive action

Western Sydney needs to protect its green space to encourage exercise.

The Western Sydney Diabetes partnership is considering a wide range of measures to improve the health of the local population, including better transport options to reduce car reliance, education programs in schools, building more green spaces and improving access to fresh food.

But those who designed the plan recognise that without policies at a federal level to drive changes in behaviour, these measures will have limited success.

Mr O'Connor said preventing diabetes would require the same level of co-ordination and bipartisanship as tobacco control, which involved targeted awareness campaigns, taxation measures and regulated advertising.

"If we were a clever society we would apply some comprehensive social engineering to reduce lifestyle-related illness," Mr O'Connor said.

This could include a sugar tax or raising the GST to encourage people to buy fresh food, which is not taxed.

Diet is considered to play a more important role in weight loss than exercise, though people who regularly exercise are more likely to maintain their weight loss as it improves their metabolism.

University of Sydney metabolic health Professor Stephen Colagiuri said the priority should be preventing people at high risk of diabetes from developing the disease, doing something at a population level to encourage healthier eating and more physical activity and making a more concerted effort to prevent pregnant women from developing gestational diabetes.

But successive attempts to bring these about had not been supported with little political will to make policies that would drive changes in behaviour.

The National Diabetes Strategy Advisory Group suggested to the government a range of measures in 2014, including the appointment of a National Diabetes Commission to implement the plan, but these had been watered down by the government, said Professor Colagiui.

"We produced a document with advice to guide their national diabetes strategy and they produced a document of their own, but their prevention part is not very strong," Professor Colagiuri said.

"We are at loggerheads with the government in regards to an implementation strategy."

Health Minister Sussan Ley said the advisory group's strategic plan was being progressed through an inter-governmental committee.

"It is important to recognise this strategy complements work also underway to develop a treatment approach for a number of chronic conditions, and we expect an Implementation Strategy to be considered by the Council and delivered by the end of this year," she said.

What are the odds?

People living in western Sydney are one-and-a-half times more likely to develop diabetes than other parts of Sydney, according to research by Wollongong University public health researcher Thomas Astell-Burt, who mapped the odds ratio of developing diabetes in different parts of Sydney.

People living in Blacktown are three times as likely to develop diabetes as those living in Mosman.

Part of this may be due to the region having higher proportions of indigenous people, people with mental health problems and people in their childbearing years, who are at higher risk.

But the prevalence of obesity in western Sydney may also be linked to the relative scarcity of fresh food and groceries compared to fast food and a built environment that is less conducive to a healthy lifestyle.

In a separate study, Associate Professor Astell-Burt mapped the food environments in Australian cities, showing that 10 to 20 per cent of Mount Druitt and Blacktown residents residents lived within a kilometre of a takeaway, but did not have access to a supermarket in the same distance.

The concept of "food deserts", which was popularised in the United States by first lady Michelle Obama, found that some areas have better access to fast food than they do to fresh food, which leads to limited opportunities to choose healthy options.

"Nobody believes that living in an area without healthy choices is a good thing and making sure that we can incentivise greengrocers and supermarkets to open, so people have access to healthy choices, is a good start," Associate Professor Astell-Burt said.

"But how do you nudge people to make those healthy choices when they're on their doorstep? So it's only part of the solution."

He recently secured a government grant to investigate which environmental factors lead to the successful management of disease.

Mr O'Connor said social demographic was part of the reason why western Sydney had higher odds of developing diabetes, but that was not the whole story.

"People are more likely to copy the behaviour that you see going on around them and for at last the last two generations there has been an increase in adopting excessive calorie intake."

Ominously, research indicates the current epidemic may be condemning the next generation, with the children of women who developed gestational diabetes 30 per cent more likely to get type two diabetes themselves.

Nearly 15 per cent of pregnant women in western Sydney develop diabetes, more than quadruple the proportion 10 years ago.

Fred Mark's misconception that diabetes was catching may prove close to the mark.