Latest research has cast doubt over the widely-held view that all ultra-processed foods (UPFs) are unhealthy. While some UPFs, such as meat products and sugary drinks, are clearly associated with an increased risk of chronic diseases, others may be less harmful, the research suggests (1). These trend-buckers include ultra-processed breads and cereals as well as plant-based alternatives.
Processed products are ousting fresh foods
Consumption of UPFs has soared around the world and today represents more than half of the daily energy intake in some high-income countries, with middle- and low-income countries following hot on their heels.
The alarm has been raised by a string of research showing that eating a higher proportion of UPFs is linked with an increased risk of weight gain, obesity and risk of chronic conditions such as cancer, cardiovascular disease, and diabetes. But the latest findings from a large pan-European study reveal that it’s not just a simple case of good versus bad. It all depends on the type of UPFs we are eating.
Investigating the effects of UPFs on health
In the first study of its kind, researchers from the European Prospective Investigation into Cancer and Nutrition (EPIC) trial investigated the relationship between UPF consumption and the risk of developing at least two chronic conditions, including cardiovascular disease and type 2 diabetes (together known as cardiometabolic diseases), and cancer (1).
The researchers assessed food and drink consumption among 266 666 healthy volunteers across seven European countries over the course of a year. They then followed these volunteers for an average of 11 years to see who developed cancer or cardiometabolic diseases.
They also investigated the consumption of individual types of UPFs and their relationship with these disease outcomes.
Overall, UPFs are associated with increased risk of long-term illness
After an average of 11 years, nearly 4 500 volunteers in the study had developed more than one of the chronic conditions being assessed. The researchers found that, as a whole, higher consumption of UPF was associated with a higher long-term risk of developing cancer and cardiometabolic diseases. For every 260 g/day increase in UPFs eaten, the study participants had a 9% increased risk of developing more than one chronic condition. Higher UPF consumption was also individually associated with a higher risk of developing cancer, cardiovascular disease, and type 2 diabetes.
Eating certain types of UPF may carry a higher risk than eating other types
But when the researchers delved deeper into the effects of nine different types of UPFs, they found a more complex story. Their results showed that animal-based products and sugar-sweetened beverages stood out as particularly concerning possible contributors to long-term health risks; both were associated with a 9% increased risk of developing more than one chronic condition for every 260 g/day increase in consumption.
Eating sauces, spreads and condiments was also linked with an increased risk of developing cancer and cardiometabolic diseases, but to a lesser extent.
Some UPF types don’t show the expected effects
In contrast, eating other types of UPFs did not seem to contribute to these long-term health risks, the study suggested. Eating sweets and desserts, savoury snacks, plant-based alternatives, and ready-to-eat/heat mixed dishes weren’t significantly associated with the long-term risk of developing cancer and cardiometabolic diseases. In fact, eating ultra-processed breads and cereals even seemed to be associated with a small reduction in the risk of these chronic diseases.
So, what does this mean for dietary choices?
These results highlight the importance of viewing the various types of UPFs separately, and raise questions about whether eating different UPFs can have different effects on our long-term health.
The mechanisms by which UPFs may influence our risk of chronic diseases are not fully understood, but there are several theories:
- One explanation could be their effect on weight gain since obesity is an important risk factor for many chronic diseases (2-4). Although UPFs tend to be more energy-dense than less processed foods, they are not equally high in their energy-density (5)
- While diets with a high proportion of UPFs have been associated with a lower nutritional quality (6), individual UPFs also differ in their nutrition profile (5)
- Non-nutritional mechanisms through which UPFs could be hazardous for health include alteration of the food matrix and the inclusion of food additives during processing (7)
This study suggests that reducing consumption of certain UPFs, particularly meat products and sugary drinks, could play a crucial role in helping to prevent cancer and cardiometabolic disease, the researchers point out. Dietary recommendations, public health policies and interventions should take account of these findings.
‘Lowering consumption of certain ultra-processed foods by replacing them with similar but less processed foods may be beneficial for the prevention of cancer and cardiometabolic multimorbidity.’ – Cordova R, et al. 2023
How are processed foods classified?
Several classification systems for processed foods have been developed to shape nutrition policy and food-based dietary guidelines. The NOVA classification system is most commonly used. It assigns foods to four groups based on how much processing they have gone through:
- Unprocessed or minimally processed – e.g., fresh, dry or frozen fruits or vegetables, grains, flours and pasta
- Processed culinary ingredients – e.g., table sugar, oils, salt
- Processed foods – e.g., cheese, simple breads, fruits in syrup, canned fish
- Ultra-processed foods – e.g., soft drinks, sweet or savoury packaged snacks, processed meat, and pre-prepared frozen or shelf-stable dishes
Find out more about NOVA and how certain foods such as yogurt can be good for you despite being classified as ultra-processed (8): see Food processing explained.
