How ultra-processed foods mess with our health

Citro's health writer Paula Goodyer unmasks the dangers of ultra-processed foods (UPFs for short), which on average, make up around 40% of an adult's daily kilojoule intake. We once blamed saturated fat, salt, and sugar for dietary woes, but this new villain has emerged on the nutritional stage and they have a complex impact on our health.

By Paula Goodyer

We used to think the main problem with so much packaged food was too much saturated fat, salt and added sugar. But now that research has turned the spotlight on ultra-processed foods, the picture is more complex.

Food processing isn’t new.  We’ve eaten some types of processed food for centuries - cheese, bread, pasta, legumes, and canned or frozen fruit and vegetables are some examples of food with some processing.  But supermarket aisles are now stocked with products created with much higher levels of processing - and there are concerns about the impact of these ultra-processed foods on our health.

These foods, including some breakfast cereals, convenience meals, instant noodles, packaged baked goods, snack foods, energy bars and toddler milks,  now make up, on average, around 40% of the kilojoules Australians consume. High intakes of these foods have been linked to a growing list of health problems like heart disease, diabetes, obesity, irritable bowel syndrome, inflammatory bowel disease, cognitive decline and dementia and a 29% increased risk of bowel cancer in men.

In fact, there’s so much wrong with these ultra-processed foods it’s hard to know where to start.

Fibre out, sugar in

But let's start here: ultra-processed foods  - or UPFs for short - are often low in fibre, which is so important for our gut and the microbes that live there. More on why a thriving gut microbiome is so important.

This lack of fibre, together with their intense, ‘moreish’ flavours from too much salt sugar or fat, make UPFs far too easy to overeat.

Not only that, but eating too many UPFs displaces the whole vegetable, fruit and wholegrain that help us and our good gut microbes to thrive. Some research also suggests that some emulsifiers, artificial sweeteners and food colouring often added to UPFs may also disrupt our gut microbes.

In addition, some ultra-food processing also takes whole food apart and puts it back together in a different form - a form that our body handles differently, says Jennifer McCann, a lecturer at Deakin University’s Institute of Physical Activity and Nutrition (IPAN).  

Toddler foods are one example - they often contain ingredients like fruit purees, fruit concentrates, and vegetable powders that are very different from the whole food they’re made from.

“They’re not fruit any more and they’re not digested the same as a whole piece of fruit would be. Fruit purees and fruit concentrates are often added to these products in such high concentration, minus the fibre, that they’re really just sugar, and should be labelled as such so consumers know what they’re buying,” says Jennifer McCann whose research has found that 85% of products marketed as toddler foods were ultra-processed.

Where did the term ultra-processed food come from?

The term ‘ultra-processed foods’ comes from the NOVA food classification system, which was developed by researchers at the University of São Paulo, Brazil. The system places food into 4 categories:

1. Unprocessed or minimally processed foods: This includes food that's eaten as nature intended, such as fruit, vegetables, milk, fish, pulses, eggs, nuts and seeds that have no added ingredients and have been little altered from their natural state.
2. Processed ingredients: This includes foods that are added to other foods rather than eaten by themselves, such as salt, sugar and oils.
3. Processed foods: These are foods that are made by combining foods from groups 1 and 2, which are altered in a way that home cooks could do themselves. They include foods such as jam, pickles, tinned fruit and vegetables, homemade breads and cheeses.
4. Ultra-processed foods: Ultra-processed foods typically have 5 or more ingredients. They usually include additives and ingredients that are not typically used in home cooking, such as preservatives, emulsifiers, sweeteners, and artificial colours and flavours. These foods generally have a long shelf life.

How can you tell if a food is ultra-processed?

Never rely on the words on the front of the pack - they might include words like ‘vegetable’ or ‘berry’ but flip it over to check the ingredients. There you might find a list of vegetable powders or a smidgen of blueberry powder, along with a bunch of additives, but no whole food.

Even the Australian Health Star Rating isn’t much help for weeding out UPFs because it only considers levels of sugar, fat and salt, and not the degree of processing. Research from Deakin University has found that 73% of UPFs had a Health Star Rating of more than 2.5 stars which suggests these foods are healthier than they really are.  

If the ingredient list is long, and there are names of ingredients you don’t understand, or ingredients you wouldn’t use in your kitchen - like hydrogenated oils, hydrolysed proteins or flavour enhancers - it’s likely to be a UPF.  Some cook-in sauces are a good example - a packet carbonara sauce for pasta based on a mix of maltodextrin, cheese powder, yeast extract, corn starch, mineral salts, onion powder, bacon powder and vegetable oil shows what a difference there is between ingredients in a UPF and a home cooked pasta dish, which requires just pasta, bacon, eggs and parmigiano reggiano to make.

The bottom line is, where possible, avoid packaged food and if you can't do that, at least ensure you recognise the ingredients listed on the back of the pack.