Silent Assassin: Dietary guidelines advice 'too carb-heavy to prevent type 2 diabetes'

That's the view of some of the prominent contributors to the Silent Assassin series, which has been exploring the causes and consequences of the type 2 diabetes epidemic stalking millions of Australians.

Eye surgeon Dr James Muecke and sports physician Dr Peter Brukner have questioned why the official Australian Dietary Guidelines give so much weight to carbs and suggest the current recommendations are contributing to a rapid rise in type 2 diabetes.

British television presenter and author Dr Michael Mosley expressed similar concerns in his recent TV series for SBS.

But not all nutrition and diet experts agree.

Overseen by the National Health and Medical Research Council, the Australian Dietary Guidelines are under review - the current ones were published in 2013 - but the process is not scheduled to be completed until 2024, and there are fears our diabetes problem will only worsen while we wait.

Experts discuss type 2 diabetes on the Voice of Real Australia podcast

An opthalmologist who has made it his personal mission to raise awareness of diabetes as Australia's leading cause of preventable blindness, 2020 Australian of the Year Dr Muecke says type 2 diabetes is a disease of carbohydrate intolerance but Australians - including those with the disease - are "being told" to follow a high-carb diet under the existing guidelines.

"We are all being encouraged to consume up to 65 per cent of our daily intake of calories as carbs, despite the fact there's no evidence to show that such an eating pattern can prevent type 2 diabetes," he said.

Dr Muecke claims the dietary recommendations, which inform national policy, are born out of "weak and unreliable epidemiological data", and that the science behind the guidelines was biased "at multiple levels".

"This body of scientific evidence, on what Australians should eat to achieve health, is certainly not as robust as we've been led to believe," he said.

"The guidelines discourage the eating of foods containing natural saturated fat, and this has in turn led to the production of thousands of 'low-fat', 'fat-free', and 'cholesterol-free' products. It has spawned an entire industry. Many of these food-like substances are highly processed and loaded with sugar and refined carbohydrates to enhance the flavour lost by removing fat. And to replace the satiety factor of fat.

"For the first time in our history, we are overfed but undernourished."

Dr Brukner, former team doctor for the Australian Olympic and cricket teams and founder of Defeat Diabetes, said the current dietary guidelines "get a lot right" in terms of restricting sugar and ultra-processed and processed foods.

But the insistence that saturated fats should be restricted, and the focus on higher carbohydrate foods needed to be addressed.

"They claim the dietary guidelines are for 'healthy Australians', and healthy Australians are probably in the minority," he said.

"Most people, especially older people, have some sort of metabolic abnormality like diabetes, hypertension, things like that. Yet the guidelines don't address those issues at all. And there are no other guidelines for those people, so by default, they tend to go with these ones anyway.

"If they got the guidelines right, they'd actually be appropriate for healthy and unhealthy people."

While he understood the process of reviewing and establishing new national nutrition guidance took time, he worries that chronic conditions like type 2 diabetes will only worsen in the interim.

"Every day counts," Dr Brukner said. "But the important thing is that they get these guidelines right this time. I'm just not confident they will."

British television presenter and author Dr Michael Mosley also criticised the Australian Guide to Healthy Eating diagram in his recent SBS TV series, Australia's Health Revolution.

He suggested the carbohydrate portion of the guidance took up "too much" of the daily recommended diet.

"We were taught to pile our plates with starchy foods, but it's the white refined carbs in this food group that can really make your blood sugars soar," Dr Mosley said. "If you're healthy, you can certainly eat starchy foods. But if your blood sugars are raised, you might want to cut them down."

But nutrition expert Laureate Professor Clare Collins, of the University of Newcastle, says it isn't the proportion of healthy carbohydrates that is the problem, but rather the "sometimes" food group - pictured just off the diagram's "plate": the chocolate, chips, soft drinks, pies, biscuits, cakes and ice-creams.

"Those foods, which aren't even on the plate, is where the unholy trinity of fat, salt and sugar come from - and on average they make up one-third of our dietary intake in Australia," Professor Collins said.

"It has even been quantified that if we could click our fingers and magically get people to eat like the recommendations suggest - where the biggest change is upping the vegetables and fruit, and decreasing the junk foods - the burden of disease attributed to diabetes would drop by 40 per cent.

"People, to me, are looking in the wrong place. They are chasing a false notion that the problem is with the Australian Guide to Healthy Eating quadrant that has the healthy carbs. It's not. The problem is the ultra processed junk foods that dominate our diet.

"If people were more opened-minded and looked at the evidence, they wouldn't be focusing on what food groups to cut out from the core foods. They'd be going after ultra-processed foods - some of which are now so processed, the combinations of how they hit your taste buds are not found in nature and that's why they are hyper-palatable and you can't stop eating them."

Professor Collins says only one person in 20 eats the recommended amount of vegetables and fruit.

"And those are the proportions we know really reduce your chronic disease risk," she said.

"My concern is that when we ignore all the junk foods that are off the plate, and say, 'Oh it's that proportion there on the Australian Guide to Healthy Eating that's focusing on healthy carbs' that is the problem. The trouble then is that people get that message of not eating 'evil' bread and potatoes, and when they realise they can't stand it, they don't go looking for a couple of slices of wholegrain bread, they are much more likely to binge on junk foods.

"The message needs to be that yes, the ultra-processed carbohydrate foods that are also high in salt, high in added sugar and high in unhealthy fats - we definitely should cut down on them.

"If we avoid those, and focus on the less processed carbohydrates, the burden of disease would drop enormously.

"You can have all the diagrams you like and argue about whether that percentage of the carbs should be smaller or bigger, but that is not the issue. The issue is you have to kick the junk foods off average Australians' plates so they are not the main driver of diet-related ill health. Not just in our country, but in most high-income countries in the world."

Professor Collins says the evidence for low-carb diets demonstrates that those strategies can help people "get started".

"But in the long term, it's about coming back to a dietary pattern that boosts your nutrient intake as well as one that you can live with permanently," she said. "And in all those patterns, the main focus is avoiding the ultra-processed foods."

As one of three team leaders involved in "systematic reviews" during the development of the 2013 national dietary guidelines, Professor Collins had a team of 30-plus dietitians with PhDs on the task.

"There were 55,000 abstracts that we had to screen - something like 22 systematic reviews - and we generated 180 evidence-based statements. It was a really strict process. Those statements were then used by the committee to generate the guidelines.

"It is a huge, laborious, costly, hard-work task, and when people criticise it glibly, it shows they haven't had that experience themselves of the conduct of these type of systematic reviews."

Professor Collins is not involved in the current review.

"The reason it took so long for them to appoint a new expert committee was because they checked everyone's credentials, and even their research grants, so you could not get on the committee if you had worked with the food industry," she said.

"Lots of people would have had their feelings hurt by not being selected. I've been around for a long time, and I have worked with different companies doing contracted reviews, so someone like me would not get picked.

"Last time there were some people from the food industry - and that was the government's choice, not the committee's choice - and this time there are absolutely no representatives from the food industry, and that should be applauded."

Professor Collins said Medicare offered chronic disease plans that allowed five visits to allied health professionals - but of those, less than 1 per cent of referrals were for dietetic consults.

"So we don't even refer people to what has been shown to work - which is medical nutrition therapy counselling by the people who have spent four to five years at university to be able to help people implement the best available evidence," she said.

"Yet we don't put any checks in place for the companies that shove ultra processed down people's throats.

"There is something fundamentally wrong that we can flood the food supply with what's not good for us and what is contributing to our national disease burden, without providing any way of at least letting people get the advice personalised to them to help them deal with it."

A spokesperson for the National Health and Medical Research Council (NHMRC) said the current review of the Australian Dietary Guidelines would take about four years, anticipating the new guidelines would be released mid-2024.

The process to appoint members to the expert review committee involved "many steps", including scrutiny by the independent Dietary Guidelines Governance Committee.

"Nutrition and the evidence which underpins the Australian Dietary Guidelines is an evolving science," she said.

"New evidence and the need to improve dietary patterns has prompted the Australian government to seek a review of new evidence and revise the 2013 guidelines. Reviewing the guidelines will ensure that Australians are provided with the most current evidence, as well as practical information on the recommended dietary patterns for good health.

"One of the challenges with the current guidelines is that less than five in 100 people eat enough vegetables and fruit. NHMRC will carry out a range of activities to make sure all relevant information is considered and prioritised for inclusion in the review."

The review would include: a "stakeholder survey" to understand how the guidelines were used and identify possible topics for review; scoping of literature to determine if new evidence was available to add further support or question recommendations in the current guidelines; and a review of food-based dietary guidelines from other countries.

"The expert committee represents a wide range of expertise to ensure the evidence and the final recommendations are accurate and appropriate for Australians," the NHMRC spokesperson said.

"The review process also includes a number of quality checks to ensure that the dietary guidelines meet the NHMRC standards including: independent methods experts, risk of bias assessments, public consultation, independent expert review and consideration by NHMRC Council.

"It is not possible to pre-empt the outcomes of the review at this stage."

A spokesperson for Dietitians Australia said the national guidelines were intended as a "framework" for eating among the healthy population, as well as those with common health risks such as excess weight.

"They are not intended to provide prescriptive dietary advice for those who have a medical condition," she said. "For those experiencing type 2 diabetes, we recommend they gain individualised dietary advice from an Accredited Practising Dietitian."

Professor Collins said Australia hadn't had a national nutrition policy since 1991. A national nutrition and physical activity "document" is due to be released imminently.

"But again, it's not a policy but a plan," she said. "Guidelines that are just words on a page that don't spill across to policy that relates to the food supply are toothless, really. We really need a nationally funded and implemented policy that goes across sectors and settings and ages and stages and chronic disease risk; one that looks at the food supply and nutrition-related health in a way that really is promoting health and wellbeing for the Australian community."