Are ultra-processed foods secretly sabotaging your diet goals? It’s time to study the labels on your favourite health-food brands. Oat milk. Cereal. Hummus. Plant-based burgers… Hands up whose weekly groceries list goes something like this? Yup, ours too. But did you know these wholesome-sounding staples are often ultra-processed foods (UPFs), linked to weight gain, diabetes and heart disease? According to latest figures, even if you avoid eating junk food such as sugary drinks and snacks, your diet is likely to be shockingly high in UPFs – including cleverly-marketed ‘health’ foods many of us eat daily.
We’re now consuming more than 50 per cent of our energy from UPFs. While their convenience and palatability is tempting, research shows this is having a potentially devastating impact on our health. UPFs tend to produce peaks and dips in blood sugar which are bad for cardiovascular health and conditions such as type-2 diabetes.
Want to protect your health or lose a few pounds? Stop counting calories and start checking the ingredients in your favourite products, say a growing number of nutrition experts. Here’s what you need to know.
WHAT ARE UPFS?
Much of our Western diet is processed to some extent. Fish is canned, peas are frozen, milk is turned into yoghurt, wheat is milled into flour. These processes are harmless and can improve food’s digestibility and nutritional value. For instance, did you know canned tomatoes are richer in antioxidant lycopene than raw ones? Most food undergoes some form of processing which isn’t a cause for concern – think cheese, sourdough bread and tofu. ‘These foods have been partially altered by adding sugar, oil, fat, salt and other culinary ingredients.’.
Problems start when food is engineered to create novel flavours and textures. Chewy chocolate cookies, doughy supermarket bread, tongue-tingling tangy tortilla chips… think of your favourite moreish foods and you can guarantee they’re UPFs. Ultra-processed foods have undergone industrial processing to become hyper-palatable,. ‘They typically contain a lot of added salt, sugar, fat and chemical additives. For instance, bread should only have a few ingredients, but white supermarket bread can have a long list of ingredients to increase shelf-life and taste.’
According to the NOVA classification system, common UPFs include reconstituted meats, sausages, salty and sugary snacks, frozen meals, biscuits, ice cream and chocolate. No surprises there. But other UPFs may come as a shock: the almond milk you pour on your cereal, the baked beans or canned soup and sliced bread you grab for lunch, that post-gym smoothie, the pesto you pop on pasta and the fruit yoghurt you have for dessert. And yes, plant-based ready meals, protein drinks and energy bars, too (see Purely plants, below).
METABOLIC MAYHEM
Once inside your body, UPFs behave very differently to the wholefoods they’re made from. Not only are they usually higher in calories, fat and sugar, but their structure (or ‘food matrix’) is also altered during processing, meaning they release these nutrients more quickly into your blood which, in turn, disrupts your metabolism.
One example is oats. ‘You could have two types of oatmeal with identical labels but totally different metabolic and long-term responses. Whole oats produce a blunted blood-sugar level response while finely ground ones [found in instant oatmeal] create a big peak in blood sugar followed by a dip, triggering hunger and inflammation.’
Similarly, fruit juices and smoothies trigger a higher blood-sugar rise and fall than fibre-packed whole fruit. The processing breaks down the original structure of the fruit. ‘Swapping a glass of orange juice for an orange gives you all the benefits of the orange, rather than just the sugar.’
HEALTH RISKS
No time to cook from scratch? The long-term health cost of eating processed foods may make you reconsider. According to a study of 77,000 people published in the American Journal of Clinical Nutrition, those who ate over half their calories from UPFs (meat- or plant-based) were 14 per cent more likely to die over 10 years. A French study of over 100,000 adults, in the British Medical Journal, found people consuming higher levels of UPFs had an increased risk of heart disease. Meanwhile, a second French study found a 10 per cent increase in UPF consumption raised the risk of cancer.
Scientists believe these effects occur because UPFs increase obesity and exposure to potentially carcinogenic chemicals (from additives and processing). But your gut health may also be involved. The ZOE PREDICT study shows a strong link between UPFs and worse long-term health, including detrimental impacts on the gut microbiome. Results revealed a diet rich in processed foods (including baked beans and juices) encouraged bad gut microbes while a minimally processed, plant-based diet led to good microbes, linked to better metabolic health.
Eating processed foods also leaves less room in your diet for protective healthy produce. ‘A diet high in UPFs is more likely to be lower in nutrient-dense foods, fibre and wholefoods,’ she says.
WEIGHT-LOSS SECRET
Do you find it hard to shed stubborn pounds despite opting for calorie-controlled meals and snacks? Ironically, they could be the problem. Your body absorbs energy more readily from low-fibre UPFs than wholefoods. Calories, of course, play a role in weight management but they’re not the be-all and end-all. ‘Very refined ingredients can have a higher caloric availability, meaning the body can access these calories far more easily than the same calories encased in fibre-rich wholefoods.’
UPFs are engineered to hit your ‘bliss spot’ so you eat more of them. Research suggests they may disrupt gut-brain signalling and stimulate appetite. Consumption of UPFs is a real problem for people who want to lose weight. ‘It’s much harder when we’re consuming these energy-dense, tasty foods that are quickly metabolised and impact our hunger and satiety signals, encouraging us to eat more.’
A landmark trial by the US National Institutes of Health compared an ultra-processed diet to a minimally processed one of the same calorie, fat, sugar and micronutrient value. Results showed people on the ultra-processed diet ate 500 more calories a day, leading to an average weight gain of two pounds in two weeks. Blood tests revealed that while on the processed diet, people had lower levels of appetite-suppressing hormones and higher levels of appetite-stimulating hormones.
WHOLE TRUTH
For anyone wanting to lose weight or improve their diet, I’d encourage them to eat food in its original form. ‘Eat whole apples rather than apple juice, for instance. Minimise UPF consumption and eat a diversity of foods. Thirty plants a week is something we should aim for to improve our gut health.’
Of course, some UPFs are worse than others. While the term “ultra-processed foods” includes foods such as confectionery, fried snacks, cakes and sugary drinks we know we should eat less of, the definition also includes foods that can be part of a healthy, balanced diet, such as sliced wholemeal bread, lower-sugar yoghurts, wholegrain breakfast cereals and baked beans.
Wholegrain UPFs, such as wholegrain breads and breakfast cereals, tend to be healthier than non-wholegrain equivalents, due to their fibre content. Wholegrain bread or cereal still has a poor glucose response but it will be better than white bread.
As always, it’s about balance but, ultimately, minimising UPFs is key to good health. When people cut down on ultraprocessed foods and incorporate more wholefoods rich in vitamins, minerals, healthy fats and fibre, they’re likely to see improved gut health, increased energy and mental clarity alongside better sleep and improved wellbeing.
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