"Ultra-processed" has become a loaded term in nutrition conversations. Here's what the research actually says.
In the mid-1990s, a Brazilian nutritional epidemiologist noticed a shift in household food purchasing: less rice, beans and cooking oil, more soft drinks, packaged bread and instant noodles. That observation led to the Nova food classification system, now widely used to categorise food by how processed it is.
The four Nova categories
- Unprocessed or minimally processed foods - fresh produce, meat, eggs, milk, rice, herbs and spices.
- Processed culinary ingredients - oils, butter, sugar, honey, salt.
- Processed foods - combinations of the above, like fresh bread, cheese or canned vegetables.
- Ultra-processed foods (UPFs) - industrially manufactured products using ingredients like high-fructose corn syrup and food additives, think soft drinks, chips, flavoured yoghurts and packaged snacks.
What the evidence shows, and doesn't
Most research linking UPFs to health issues is observational, meaning it can show an association but not prove cause and effect. A large 2024 review found UPF consumption was associated with a range of health issues, including heart disease, type 2 diabetes and some mental health conditions. Some nutrition scientists caution against grouping very different foods, like soft drinks and wholegrain bread, under one label, since the evidence of harm is stronger for some UPFs than others.
Most experts agree the relationship between diet and health is complex, and no single food category tells the whole story.
A practical starting point
Until more clinical research is available, many nutrition experts suggest leaning towards home-cooked meals and minimally processed ingredients where practical, without needing to eliminate every packaged food from your diet.
