Australians are eating more ultra-processed foods amid the rising cost of living. How can we turn that around?

Ultra-processed foods like chicken nuggets, sweet breakfast cereals and fizzy drinks aren't entirely bad. 

They're often cheap and easy to prepare, and they keep for longer on the shelf.

They're also scientifically developed to be what the human brain considers tasty.

But they often contain high levels of fat, salt and sugar, meaning there are serious health risks that come with their long-term consumption.

Experts say Australians have now reached a point of dependence on ultra-processed foods, as cost-of-living pressures push healthier options out of reach for many.

Amanda Lee from the University of Queensland's School of Public Health says for an average Australian family of four, 61 per cent of the food budget goes towards unhealthy food and drinks.

"I just find that really revealing," Professor Lee says.

So how did we get here? And is it possible to turn back the clock?

The beginning of food preservation

When food processing first took off in the early 20th century, the industry was wildly unregulated, says Kevin Hall, from the US National Institute of Health.

He says companies were experimenting with adding chemicals to try to preserve products for longer, sometimes with dangerous consequences.

"It was actually one of the reasons why the Food and Drug Administration was created in the United States [in 1906], because of all of the adulterants in foods," Dr Hall tells ABC RN's Rear Vision.

"There was a big wave of … really acute food illness that was caused by manufacturers trying to make cheap foods available to people that were preserved as best as they possibly could.

"Now we have an analogous problem; [processed foods] are making people sick chronically [with] diabetes and cardio metabolic diseases."

The turning point for food processing was World War II, as resources were poured into figuring out how to make food that could be stored for months, and easily transported to feed thousands of soldiers overseas.

It resulted in what culinary historian Laura Shapiro describes as "a bonanza of canned meats" on offer in the US, including the "indestructible luncheon meat known as Spam".

"There were canned ham and sweet potato dinners, canned pork with apple sauce, canned bacon, they had dehydrated potatoes, they had powdered orange juice," Ms Shapiro says.

Redefining 'cooking'

After the war, however, Ms Shapiro says food companies faced a difficult challenge: convincing people that not only was processed food tasty, but that it was an acceptable substitute for a meal cooked from scratch.

"[It] was a very, very big thing [to change] the psychology of cooking, to redefine the word 'cooking' so that it meant opening a box," she says.

Then along came fast food.

In the 1950s, McDonald's rapidly gained popularity in the US, and the first Australian outlet opened in Sydney in 1971.

Ms Shapiro says the fast food giant changed the cultural idea of what a meal looked like.

"Technically it was a meal, that is to say it was a hamburger and French fries," she says.

"But there was nothing around it that made it a meal. You may not even have sat at a table to eat it."

Microwaves, which became a common household appliance in the 1980s across both the US and Australia, were another boost for processed foods.

"The food industry immediately produced, with microwave ovens in mind, a gazillion things," Ms Shapiro says.

"Every single thing on earth was made in single-serving, microwavable form."

'Ultra-processed food' defined

In the late 2000s, the processed food industry was dealt a significant blow. 

The NOVA food classification system was developed by a group of researchers, led by Carlos Monteiro, at the University of Sao Paulo in Brazil.

It meant, for the first time, foods were classified based on their level of processing, rather than their nutrient profile. And there was a separate category for "ultra-processed foods".

American molecular biologist and nutritionist Marion Nestle says ultra-processed foods are essentially anything that can't be made at home.

Take products made with corn, for example.

"Corn on the cob is unprocessed, canned corn is processed, and Doritos chips are ultra processed," Dr Nestle says.

"You can't make those. You don't have the flavours, you don't have the additives and you don't have the machinery."

Once a definition was established, studies were then undertaken on the impacts of eating ultra-processed foods.

In 2019, Dr Hall led the first randomised trial of 20 healthy adults. 

The participants were all given two diets which were matched nutritionally, but one was made up of ultra-processed foods and the other of minimally processed foods.

Dr Hall says they found people ate a lot more of the ultra-processed foods — about 500 calories more per day.

The exact reason for this is unclear. However neuroscientist and obesity researcher Stephan Guyenet says the concentration and combination of fat, sugar, carbs and salt in ultra-processed food makes them scientifically harder to stop eating.

"Those are properties that tend to cause dopamine release in the brain, which is a chemical that's responsible for learning and motivation, including for food," says Dr Guyenet, who is also the author of The Hungry Brain.

Where are we now?

Today, we know ultra-processed foods don't suit most of our diets.

Yet, Professor Lee says ultra-processed and "discretionary" — or junk — food and drinks are taking up a progressively bigger chunk of Australians' overall diet.

"However people define … junk foods, whether it's ultra processed foods or discretionary foods ... we know that for most Australians, there's very little room in our sedentary lifestyle to consume any of those foods.

But Phil Baker from Deakin's School of Exercise and Nutrition Sciences says getting people to change their diets is complicated, especially in the current cost-of-living crisis.

He says Australia has become dependent on ultra-processed foods, especially among the lowest socio-economic groups, as it's cheaper to buy instant noodles, for example, than fresh fruit, vegetables and meat.

"It's very hard for us to come along and say we should be taxing, regulating these foods that are so cheap [when] so many are relying on them to just feed themselves [and] feed their families," Dr Baker says. 

New tech improving access

It should be noted that not all food processing is inherently harmful. New technologies are emerging that give foods longer shelf-lives, without depleting them of nutrients. 

Warren Hunt from Charles Darwin University and his team are exploring how thermal heat and drying technology can be used to process fruits, meats and vegetables to distribute to some of those most reliant on unhealthy food — Australia's remote Aboriginal communities.

"We're not trying to reinvent tin corned beef or tinned Spam, we're looking at novel technologies that enable clean-label, higher quality products to be produced," Dr Hunt, leader of the Northern Australia Food Technology Innovation Project, says. 

"In other words, they don't necessarily have to be filled with salts and other preservatives.

Dr Hunt says a distribution facility in the Northern Territory, which he hopes to secure funding to pilot, would mean people who often don't have reliable access to a fridge or cooking facilities could have healthier options on their shelves. 

All Australians should have reliable access to healthy food, regardless of their postcode or income, he says.