The UPF Paradox: Why Experts Disagree on Ultra-Processed Foods' Health Impact

You stand in the supermarket aisle, reading ingredient lists on boxes of cereal and frozen meals, wondering if what you're putting in your trolley will hurt your family. The anxiety is real. Over half the calories consumed in the UK come from ultra-processed foods—products with more than five ingredients, often including things like emulsifiers, additives, and flavorings that don't live in a normal kitchen. The evidence linking these foods to obesity, cardiovascular disease, diabetes, mental health problems, and premature death keeps growing. But here's the puzzle: nobody can agree on why they're harmful.

Dr. Chris van Tulleken, who has written books and made documentaries about the dangers of ultra-processed foods, says they're "almost impossible to avoid"—even his own family eats some. Yet when a dietitian named Maeve Hanan, a member of the British Dietetic Association, examined a typical shopping list, she paused at a box of bran flakes and said something unexpected: "This is ultra-processed, but I often buy this for my family. It's got so many health benefits." Hanan worries about what she calls a "growing hysteria" around these foods, driven by messaging that splits the world into good and bad. "This food is good. This food is bad," she says. "It just fuels fear—and fear around food is never good."

When Hanan reviewed the full shopping list, her verdict was reassuring. Yes, there were ultra-processed items, but the overall mix covered each food group reasonably well. She explained that a long ingredient list doesn't make something inherently bad—nutritional value matters far more. Take chicken nuggets, the kind that make parents feel guilty. Hanan pointed out that UK manufacturers are required to add vitamins and minerals like calcium carbonate, niacin, and thiamin to white wheat flour. The raising agents with chemical-sounding names like disodium diphosphate have all been tested and approved under UK food laws. "While chicken nuggets are a good source of protein," she said, "they are higher in fat and salt than a plain chicken breast, so I would eat them in moderation as part of a balanced diet." The key insight: one food does not make a diet healthy or unhealthy. Balance over time is what counts.

But the scientific disagreement runs deeper than messaging. Some researchers argue the problem is simply the high fat, sugar, salt, and calorie content of these foods. Others suggest the processing itself changes how our bodies respond—making foods easier to overeat, or altering our gut microbiome in harmful ways. Prof. David Julian McClements, a food scientist who works with the food industry, says the "ultra-processed food idea is not very well defined" and that focusing on processing is "a bit of a red herring." He argues there's no conclusive evidence that processing alone inherently damages health, and he advocates for redesigning processed foods to make them healthier rather than abandoning them altogether. Convenience, he points out, is a major part of modern life.

Van Tulleken pushes back hard. "UPFs are tasty, they are moreish—that's the whole point," he says. "Of course, we can make UPFs healthier—but then they're not as nice. The food companies know very well how to make healthy food. The reason they don't is because it's not profitable." He points to growing evidence that industrial processing does affect our health and argues that better food labeling is essential so people know which products are high in fat, sugar, and salt. The Food and Drink Federation, representing UK manufacturers, counters that it has invested millions in healthier product innovation and cut salt, sugar, and calories from products by almost a fifth in just five years, all in line with government regulation.

Megan Bamford, a mother of two, found that cutting ultra-processed foods helped her manage irritable bowel syndrome and chronic pain. But cooking from scratch isn't always realistic when you have young children. Her seven-year-old daughter, Ella, has struggled with severe picky eating since childhood and has been ill because of it. Megan's kitchen now holds both fresh produce and packaged cereals, crisps, and biscuits. She looks for snacks with five ingredients or fewer when she can, but she's made peace with the reality: "I feed my children in the best way I can, I choose the healthiest options I can find." This is the lived experience behind the debate—not ideology, but the messy work of keeping a family fed and healthy.

As you place four chicken nuggets on your child's plate alongside raw carrots and pasta, the shame and panic that once accompanied such choices begins to lift. Your son is active, he doesn't eat nuggets every night, and he's eaten from multiple food groups throughout the day. He grins and says, "This is the best tea ever, Mummy." The question of whether ultra-processed foods are inherently dangerous remains unresolved among experts, but the practical answer—that balance, moderation, and overall dietary patterns matter more than any single food—is becoming clearer.