Real Food, Real Health

Walk down any supermarket aisle and you'll find thousands of foods our great-grandparents wouldn't recognise: breakfast cereals, flavoured yoghurts, protein bars, ready meals, soft white bread that stays fresh for a week. These are ultra-processed foods, and in the UK they now make up more than half of everything we eat.¹ Over the past few years, they have become one of the most talked-about subjects in nutrition, and the research is hard to ignore.

What makes a food "ultra-processed"?

Almost all food is processed in some way. Chopping, freezing, fermenting and cooking are all forms of processing, and many are wonderful. To make sense of it, scientists in Brazil created the NOVA system, which sorts foods into four groups:²

• Unprocessed or minimally processed foods: fresh, frozen or dried vegetables, fruit, beans, lentils, grains, nuts, eggs, milk, meat and fish.
• Culinary ingredients: olive oil, butter, salt, honey and vinegar, used to cook with.
• Processed foods: simple combinations of the first two, such as traditional cheese, tinned fish, sourdough bread and tinned beans.
• Ultra-processed foods: industrial products made mostly from refined ingredients (starches, sugars, oils and proteins), often with additives you wouldn't use at home, such as emulsifiers, flavourings, colours, sweeteners and modified starches.

A simple test: if the ingredients list is long and includes things you wouldn't find in a home kitchen, it is probably ultra-processed.

What the research shows

• Linked with many chronic diseases. An umbrella review in the BMJ, bringing together 45 meta-analyses and almost ten million people, linked high intakes of ultra-processed food with 32 health problems. The strongest evidence was for death from heart disease, type 2 diabetes, anxiety and depression.³ (See Where Body Care Meets Mind.)
• A major Lancet series in 2025 reviewed 104 long-term studies and found that 92 of them reported a higher risk of at least one chronic disease with diets high in ultra-processed food.⁴
• It makes us eat more. In a carefully controlled US trial, people ate about 500 more calories a day and gained weight on an ultra-processed diet, compared with a minimally processed diet matched for sugar, fat, fibre and salt.⁵
• Even "healthy" ultra-processed food. In a UK trial, people following the government's healthy eating guidelines lost about twice as much weight when their meals were minimally processed rather than ultra-processed, even though both diets were nutritionally balanced.⁶

Most of this evidence comes from large studies that follow people's diets and health over many years. That reflects the nature of the subject, not a weakness in the findings. Science works best when it can isolate one thing and measure it, but real diets are made of thousands of foods eaten over a lifetime, and it would be neither possible nor ethical to make people eat ultra-processed food for decades to see who falls ill. It was this same kind of evidence that first showed smoking causes lung cancer. When many large studies across different countries consistently point the same way, and controlled trials and laboratory research help explain how the harm happens, the case is strong, even if no single study can pin down one cause. The UK's scientific advisers have called for more research into exactly how these foods affect us,⁷ but the trials above, the consistency of the findings and our growing understanding of why they may harm us all point in the same direction.

Eat food your great-grandmother would recognise.

Why might they harm us?

• Designed to be hard to stop eating. The careful balance of sugar, fat, salt and crunch can override the body's natural fullness signals.
• Soft and quick to eat. Many need little chewing, so we eat them fast, before the gut's fullness hormones have time to work. (See The Hormone Web.)
• Missing what matters. Refining strips out fibre, vitamins, minerals and the protective plant compounds that whole foods bring.
• Additives and the gut. Some common emulsifiers thinned the protective mucus layer of the gut and promoted inflammation in animal studies, and in a human feeding trial, the emulsifier carboxymethylcellulose changed gut bacteria and their products.^8,9 (See The Master Regulator.)
• Sweeteners. The World Health Organization advises against using non-sugar sweeteners to control weight.¹⁰ In 2023, its cancer agency classified aspartame as "possibly carcinogenic to humans",¹¹ and in a large French study, people who consumed the most artificial sweeteners, especially aspartame and acesulfame-K, had a higher risk of cancer.¹² The sweetener erythritol has been linked with stickier blood platelets and a higher risk of heart attack and stroke,¹³ and in a Brazilian study following more than 12,000 adults for eight years, those with the highest sweetener intake showed a faster decline in memory and thinking, equal to about 1.6 years of extra brain ageing.¹⁴ Nor are sweeteners a good answer to high blood sugar. In a controlled trial, just two weeks of saccharin or sucralose changed gut bacteria and worsened the body's handling of blood sugar in healthy adults,¹⁵ and in the large French study, people who consumed the most artificial sweeteners had a higher risk of developing type 2 diabetes.¹⁶ Regulators still consider sweeteners safe within set limits. But studies of real people over many years can't isolate one ingredient from a lifetime of eating; what they can show are patterns, and these patterns are consistent enough to take seriously. There is little reason to make sweeteners a daily habit.
• Packaging. Ultra-processed foods often come wrapped in plastic and coated cartons, which can pass chemicals into the food, especially when it is fatty, acidic or heated. Bisphenol A (BPA) disrupts hormones; Europe's food safety authority cut its safe daily limit 20,000-fold in 2023, and the EU has since banned it from food packaging.¹⁷ The phthalate DEHP, used to soften plastics, is classed as possibly carcinogenic, and PFOA, one of the "forever chemicals" (PFAS) once used in grease-proof packaging, is now classed as carcinogenic to humans.¹⁸ (See Lightening the Load.)
• Blood sugar swings. Refined starches and sugars, without fibre to slow them down, send blood sugar up and down. (See Balancing the Sugar Seesaw.)

Built to be craved: are they addictive?

Many people feel they simply can't stop at one biscuit or one handful of crisps, and there may be good reason. A review of 281 studies from 36 countries, published in the BMJ, estimated that around 14% of adults and 12% of children show signs of addiction to ultra-processed foods, measured using the same criteria as for alcohol and tobacco, such as intense cravings, loss of control and carrying on despite harm.¹⁹ Foods high in both refined carbohydrate and fat, a combination rarely found in nature, seem to trigger the brain's reward system particularly strongly. In one study, eating a small high-fat, high-sugar snack every day for just eight weeks changed how the brain's reward centres responded to food.²⁰

"Food addiction" isn't yet an official diagnosis, and scientists are still debating which foods and ingredients are most to blame. But if you find certain foods hard to resist, it isn't a lack of willpower: many of these products are engineered to be hard to stop eating. The good news is that cravings usually fade within a few weeks of eating mostly real food.

The health halo trap

Some of the most ultra-processed foods are marketed as healthy: protein bars, "low-fat" flavoured yoghurts, breakfast cereals with added vitamins, meat-free sausages, "multigrain" supermarket bread, sweetened plant milks and diet drinks. A label saying "high protein", "low fat" or "plant-based" tells you nothing about how processed a food is. Turn the pack over and read the ingredients instead.

Stepping away, simply and affordably

You don't need to be perfect. Every ultra-processed food you swap for real food counts, and many swaps save money:

• Make the most of good "processed" foods. Frozen vegetables and berries, tinned tomatoes, beans, lentils and fish, oats, plain yoghurt and traditional cheese are affordable, nutritious and quick.
• Bake a simple loaf. Our Seeded Nut and Oat Loaf and Golden Linseed Loaf need no kneading and keep you fuller for longer than shop-bought bread.
• Make your own sauces and dressings. A vinaigrette, tomato sauce or pesto takes minutes and contains nothing you can't pronounce.
• Choose plain, then add. Plain or homemade yoghurt with berries and nuts instead of flavoured pots; porridge or Bircher muesli instead of sugary cereals.
• Cook once, eat twice. Soups, stews and dals freeze beautifully and are the best answer to the ready meal.
• Snack on real food: fruit, nuts, seeds, hummus with vegetables, or a square of dark chocolate.

Our recipes are all made from real, whole ingredients, and many take less than 20 minutes. For eating well on a tight budget, see Closing the Divide.

At Rootwise, we believe food is our first medicine. We'll help you find realistic, affordable ways to bring more real food into your life, one meal at a time, in a way that suits your body, your tastes and your week.