Close to half of the calories eaten by Australians each day come from ultra-processed foods. New research from our team at the Food & Mood Centre has linked these foods to poor health and early death. But what are ultra-processed foods and why should we pay more attention to them for the sake of our health?
What are ultra-processed foods?
In 2009, a food classification system known as ‘NOVA’ defined ultra-processed foods as “industrial formulations generated through compounds extracted, derived or synthesised from food or food substrates, containing five or more ingredients and artificial additives, with no wholefood components”.
Put simply, these foods are made in factories, are highly refined and contain little, if any, intact food.
Ultra-processed foods are also known for containing high amounts of nutrients such as sugar, saturated fat and salt in addition to excess energy or calories. And on the flip side, they’re usually low in protein, fibre and essential vitamins and minerals.
In Australia, 42% of our calories come from ultra-processed foods. The most common culprits are:
- Highly refined industrialised and mass-produced breads, including white bread with many unrecognisable ingredients
- Frozen and shelf-stable ready-to-heat or ready-to-eat meals, including frozen pasta, pies and nuggets
- Fast food dishes, including hamburgers, pizza and French fries from fast food outlets
These are closely followed by pastries, buns and cakes, breakfast cereals, biscuits, fruit drinks and iced teas, and confectionary.
According to NOVA, and to really put things in perspective, ultra-processed foods differ from other terms you may be familiar with (e.g. processed foods) in that they require sophisticated technology, equipment, manufacturing and ingredients in order to create highly palatable, convenient, profitable and mass-produced goods.
On the other hand, processed foods are characterised by NOVA as using salt, oil or sugar and more traditional preserving methods (e.g. bottling and fermentation) to increase the durability of food.
For example, mass-produced bread made from complex ingredients never or rarely used in kitchens including emulsifiers, preservatives and colourings is regarded as ultra-processed, but bread made from simple ingredients such as flour, water, salt and yeast is typically considered processed.
Why should we care about ultra-processed foods?
The consumption of ultra-processed foods has markedly increased in recent years and that’s probably because we’re surrounded by them and exposed to considerable marketing strategies.
Ultra-processed foods may also be perceived as relatively cheap, tasty and convenient as well as having the potential to prevent food waste (because of their extended shelf-life) compared to healthier foods, especially fresh produce. All of these factors could certainly be seen as beneficial attributes.
But concerns arise when ultra-processed foods replace a significant proportion of freshly prepared dishes made from unprocessed or minimally processed wholefoods, which are important for our health and wellbeing.
What can happen when a significant proportion of what we eat comes from ultra-processed foods?
Our recently published systematic review and meta-analysis investigated the link between ultra-processed food consumption and chronic diseases as well as mortality. It included 43 studies and a combined sample size of close to 900,000 children, adolescent and adult populations across the globe.
When we combined or synthesised the results from several studies with the same outcome, we found that eating higher amounts of ultra-processed food was associated with greater likelihood of overweight, obesity, abdominal obesity and metabolic syndrome in adults as well as some respiratory conditions in adolescents. Higher consumption was also linked with a greater risk for the development of depression and all-cause mortality in adults.
When we systematically reviewed the literature, we also found that eating more ultra-processed food was associated with higher risk of type two diabetes mellitus, frailty, irritable bowel syndrome, cardiovascular diseases (and some but not all associated risk factors), breast cancer and overall cancer in adults. Higher consumption was also associated with metabolic syndrome in adolescents and dyslipidaemia in children.
What can and can’t current research tell us?
Although our study showed that the more ultra-processed foods we eat, the greater our risk of various chronic physical diseases, mental health disorders and mortality, it was limited to including only observational studies.
So, for example, we can’t tell whether common mental disorders such as depression cause us to eat more ultra-processed foods, or whether ultra-processed foods cause the development of depression.
There has only been one randomised, controlled trial to date that has assessed the cause-effect relationship between ultra-processed food consumption and health outcomes. It is important to emphasise here that this type of study (i.e. a randomised, controlled trial) is considered the crème de la crème of clinical research, especially in the nutrition space where it is often difficult to fully capture what people are eating versus what they say they are eating.
And although we’ve mentioned ultra-processed foods typically contain adverse levels of certain nutrients (i.e. high sugar, fat and salt, with low protein, fibre, vitamins and minerals), this study very cleverly matched the levels of nutrients across both the ultra-processed diet and its comparator — an unprocessed or minimally processed diet.
The ultra-processed diet in this study also didn’t rely on foods and beverages such as chips, lollies, pizza and sodas etc. (as you might’ve imagined), it was mostly made-up of inconspicuous foods that we as Australians eat every day (e.g. industrialised and mass-produced packaged breads as well as frozen and shelf-stable ready-to-heat or ready-to-eat meals, such as beef ravioli pasta).
While the possible underlying mechanisms for how and why ultra-processed foods impact us in this way are still uncertain, the matching of nutrients across both diet types suggests that something other than the nutrient profiles of ultra-processed foods may be driving their effects.
More research is undoubtably needed before conclusions are drawn, but the current state of play suggests that limiting our intake of ultra-processed foods and replacing them with unprocessed or minimally processed foods (including, for example, foods from traditional diets such as the Mediterranean diet) may reduce our risk for chronic diseases and mortality.
So how can we identify ultra-processed foods when shopping?
Ultra-processed foods can be tricky to pick, but briefly, they usually come in packages and contain ingredients that you wouldn’t typically use in home-cooking. And as previously mentioned, many are high in sugar, saturated fat, salt and calories, while being low in protein, fibre and essential vitamins and minerals.
For these reasons, looking at the ingredients list on packages can be useful. A few simple label-reading tips to choose healthier foods and drinks can be located here.
If you find five or more ingredients – as well as ingredients you don’t recognise (e.g. high-fructose corn syrup, hydrogenated or interesterified oils and hydrolysed proteins as well as artificial food additives expressed as numbers, alphanumeric codes or chemical compounds) – chances are you’re dealing with an ultra-processed food.
Ultra-processed foods may also be tricky to pick because depending on how they’ve been made, the same type of food could be considered 1) unprocessed / minimally processed, 2) processed or 3) ultra-processed.
The transformation of whole oranges into homemade juice versus dried or dehydrated preserved orange slices versus store-bought orange juice may provide a clear example of applying these categories to same type of food (see below).
1) unprocessed / minimally processed = whole oranges are peeled and separated into segments or freshly squeezed for consumption
2) processed = whole oranges are sliced, excess juice is removed, and slices are placed in an oven or dehydrator to dry for preservation and later consumption
3) ultra-processed = whole oranges are washed and squeezed by a machine where pulp, oils and oxygen are removed (removal of oxygen helps to prevent oxidative damage to vitamin C during storage). The juice is then heated or pasteurised to inactivate enzymes and kill potentially harmful microbes, and then artificial food additives including preservatives, colours and sweeteners are added. This is the type of orange juice we can buy from stores. And this kind of intensive manufacturing means store-bought juice can be kept in large tanks for up to a year before packaging and reaching our shopping trolleys.
What can I do to reduce my intake of UPFs?
Here are our top simple tips to help reduce your intake of ultra-processed foods:
- Where possible, opt for wholefood items and ingredients in place of ultra-processed foods by shopping in the vegetable/fruit/meat/dairy sections rather than the middle isles of the supermarket where most ultra-processed foods are located.
- Accessing cheap and sustainable healthy foods doesn’t always come easy! If fresh food is not available or affordable, even looking for less processed alternatives with a higher nutrient content can be beneficial. For example, instead of selecting white bread, select whole-wheat bread with minimal ingredients. Comparing the salt content of various breads in the supermarket and checking for the presence of emulsifiers can be helpful tricks. You could also swap flavoured yoghurt containing additives for plain or natural yoghurt. And for an extra boost of nutrients and sweetness, top with your favourite fresh or frozen fruits.
- In many cases, frozen and canned vegetables are nutritious and affordable options. If opting for canned or tinned varieties (e.g. canned tomatoes, tinned corn), take care to select products that are ‘reduced salt’ or have minimal or no salt and sugar added.
- Another way to increase your intake of healthier foods and nutrients, with the added benefit of decreased prices (and even tastier fresh foods!), is to buy and eat fruits and vegetables that are in season.
- For some recipe ideas from the Food & Mood Centre team and for extra information about our research and up-to-date findings in the nutrition space, click the link here.
Melissa is a PhD candidate within Deakin University’s Food & Mood Centre. She holds a Bachelor of Nursing (Pre-registration), Graduate Diploma in Psychology and Bachelor of Psychological Science (Honours). Meghan Hockey is an Accredited Practising Dietitian and a PhD candidate with the Food and Mood Centre. Dr Wolf Marx is an Accredited Practising Dietitian and Alfred Deakin Postdoctoral Research Fellow at the Food and Mood Centre.