There is a lot of interest in ultra-processed foods (UPFs) at the moment, but how worried should be?
UPFs, also known as 'industrially produced edible substances', are foods that have been processed to the point that they no longer resemble their original ingredients. UPFs include soft drinks, breakfast cereals, ice-cream, mass-produced bread and frozen meals. They are extensively branded, packaged and marketed. Dr Chris van Tulleken, one of the leaders in this field, describes them as a product wrapped in plastic, containing an ingredient you wouldn’t find in your kitchen at home.
The NOVA diet classification system looks at the processing and places food in groups 1-4. If NOVA 1 is an apple (in its whole form), NOVA 2 would be apple juice with most of its fibre removed. NOVA 3 is where further ingredients are added, such as a home-made apple crumble. The apple is still there but alongside flour, sugar and butter. This is still a home-cooked product though, created in a kitchen rather than a laboratory.
NOVA 4 goes one step further and this might include a shop-bought apple crumble, created with techniques not found in a kitchen and containing completely unpronounceable ingredients.
It is a widely used classification method - although far from perfect; with criticism that relatively ‘healthy’, cheap foods such as fish fingers and baked beans are unfairly grouped.
UPFs are created to have a long shelf-life, to be cheap, profitable and convenient to eat or heat. They are not created with nutrition as a priority and ingredients might include additives, preservatives, stabilisers, emulsifiers, solvents, binders, boosters, sweeteners, flavourings and dyes.
Dr Chris van Tulleken’s recent book ‘Ultra-Processed People’ has an eye-popping chapter on additives. He details how xanthan gum, found in everything from sauces to toothpaste, is a ‘bacterial exudate'. Put simply, it is ‘slime that bacteria produce to allow them to cling to surfaces’. It feels like oil in the mouth but doesn’t contain oil. Manufacturers reduce their costs and supposedly improve consumer health. With slime.
Or take ubiquitous palm oil. When freshly pressed it is full of colour, flavour and antioxidants. Food companies require none of this for their biscuits and cakes, so it is refined by heat, neutralised, bleached and deodorised, barely resembling the oil it started as.
These lab ingredients help make food long lasting and hyper-palatable. UPFs are generally high in starch, sugars, inflammatory oils but low in vitamins and minerals. They are created to hit the ‘bliss point’, a combination of fat, sugar and salt not found in nature. When these combine (think ice cream, doughnuts, crisps) they trigger reward pathways in the brain and dopamine release. Dopamine is the chemical messenger involved in feelings of reward, euphoria and pleasure so it drives excessive consumption.
Some have argued that these foods are similar to addictive drugs, which are also processed and concentrated forms of naturally occurring substances. Although further research is needed to say definitively if UPFs are in fact addictive.
A major difference in 2023 compared to previous generations, is that UPFs are no longer an occasional treat but make up the majority of our calories. UPFs total 56.8% of energy intake in the UK diet, and worryingly this percentage is higher for children (74.9%) and adolescents (83.9%).
UPFs have been shown to increase risk of certain cancers, obesity, type 2 diabetes and cardiovascular disease. Higher consumption is linked with a 62% increase for mortality.
They have also been shown to disrupt hormones leading to depression, fatigue and hunger, as well as altering the body’s microbiome.
But it isn’t just the ingredients of UPFs that are problematic, it is also how the food is made. Often a myriad of ingredients are combined using processes, such as hydrogenation, for which there is no equivalent in the home.
Hydrogenation is where manufacturers add hydrogen to liquid fat, such as vegetable oil, to turn it into solid fat at room temperature. In short, this is how oil becomes solid, such as margarine. The more hydrogen used, the harder the resulting fat. A by-product of the process is trans-fats. Many scientists believe these are the worst type of fat for the human body.
A recent study set out to explore whether the processing of UPFs made any difference to weight gain. Although a relatively small study, the experiment was very simple; it compared two groups, one eating a diet of 80% UPF and the other 80% NOVA group 1 foods. But importantly the diets were matched in terms of salt, sugar, fat and fibre, and there was no restriction on how much food participants could eat. The experiment lasted for 2 weeks, before each group swapped over and ate the other diet.
Unsurprisingly, the unprocessed diet was more expensive and took longer to prepare.
Results showed that the speed at which the participants ate the UPF diet was faster (possibly as softer food is easier to chew and swallow), delaying the satiety signal. Those on the UPF diet ate on average 500 calories more per day versus the unprocessed diet and in turn gained weight. Participants on the unprocessed diet actually lost weight, even though they could eat as much as they liked.
We live in a culture that promotes and normalises UPFs. It is almost impossible to avoid them altogether, especially when many of our cultural touchpoints centre around these types of foods. There is also no denying their convenience and affordability – so don’t beat yourself up if UPFs make up a significant part of your diet, you are not alone.
Gaby Richards will be hosting a course on this topic, created for those who want to learn more about how to reduce UPFs in their diet. 'What are UPFs and how to reduce them', will run between 19th February - 3rd March and will include tips, advice and recipes. Please head to the 'services' page of this website for further information.
