There are no clear agreements on what features make food more or less processed, according to research by the University of Surrey and the European Food Information Council.
Classification systems that categorise foods according to their “level of processing” have been used to predict diet quality and health outcomes, inform guidelines and in product development.
However, having reviewed 100 scientific papers the researchers found that
“food processing and the degree of processing used are interpreted in different ways by different classification systems”.
“It is concerning that there are no clear agreements on what features make food more or less processed, and how this relates to healthy eating advice, which may make it more difficult for consumers to make informed choices consistently,” said Christina Sadler, a postgraduate researcher and PhD candidate at the University of Surrey and senior manager at EUFIC, who led on the research.
For example, in some classifications there was a failure to include measurements of nutritional content. In their paper for Trends in Food Science and Technology, the authors contrast this with nutrient profiling schemes such as Nutri-score, which converts the nutritional value of products into a simple code consisting of five letters.
Only a few of the classification systems examined in the analysis also acknowledge food processing done at home, instead focusing more on industrially processed foods. This omission is “misguided”, they noted, because homemade food “is not automatically a healthier choice”.
They also considered how ‘ultra-processed’ foods are defined. There is a lot of confusion and disagreement about the term, but it is thought that these foods “could relate to obesity by energy density and food properties such as texture”.
The British Nutrition Foundation has also picked up on the confusion. “Many foods that would be classified as ultra-processed may not be recognised as such and, while many ultra-processed foods are nothealthy options, this isn't always the case,” explained BNF science director Sara Stanner.
Indeed, as well as crisps, cakes, sweets, chocolate and sugary drinks, ultra-processed foods can include sliced wholemeal bread and vegetable-based pasta sauces.
A survey by the BNF, published in February, showed that 70% of Brits had not heard of the term ultra-processed food. However, 36% said they are trying to cut back on some kind of processed foods.
BNF’s Stanner warned against demonising all processed foods. “There can be a very judgmental attitude towards processed foods, implying that you cannot be eating well if your diet is not made up entirely from 'real food' that is cooked from scratch,” she explained. “But, most foods we eat are processed in some way and processed foods help a lot of us to prepare meals within the limited time and budget we have.”
Sadler, at the University of Surrey said: “What is needed is clarification of the underlying methods, meanings and rationales of food classification systems so that foodstuffs can be classified consistently. This will help inform public health and ensure we eat a more balanced diet.”