You’ve Been Lied to About Ultra-Processed Food
Someone asked: “Is all processed food bad? Do I have to avoid everything in the middle aisles?”
Here’s what the actual research says. Professor Sarah Berry from King’s College London — the woman behind the massive ZOE health studies — found it’s not 65% of processed food we should worry about. It’s only 20 to 25% of what’s on UK supermarket shelves that’s processed in a way that genuinely harms health.
The rest? Ranges from perfectly fine to actively beneficial. Tinned beans. Frozen vegetables. Whole grain bread with four ingredients. The UPF panic has people terrified of food that’s helping them, not hurting them.
The 20% Reality: Not All Processing Is Equal
Professor Sarah Berry runs the ZOE research studies. Thousands of participants. Continuous glucose monitors. Blood tests. Proper science, not Instagram hysteria.
Her finding: only 20 to 25% of supermarket food is high-risk ultra-processed. That’s the stuff with ingredient lists longer than this sentence, additives you can’t pronounce, and formulas engineered to be hyper-palatable.
The other 75 to 80%? Includes minimally processed foods that are perfectly healthy.
What counts as “fine” processing:
- Tinned tomatoes (3 ingredients: tomatoes, salt, citric acid)
- Frozen spinach (1 ingredient: spinach, flash-frozen)
- Whole grain bread (flour, water, yeast, salt)
- Natural yogurt (milk, live cultures)
- Tinned fish (fish, water, salt)
Some processing preserves nutrients. Flash-freezing vegetables locks in vitamins better than fresh veg sitting in your fridge for a week. Tinning tomatoes at peak ripeness captures lycopene that degrades in storage.
But the NOVA classification system lumps them together. Fresh bread from a bakery and a factory sponge cake both get called “ultra-processed.” That creates unnecessary fear and makes healthy eating feel impossible.
Why Food Matrix Matters More Than NOVA Classification
Here’s what actually determines whether food causes problems: texture, not category.
Professor Berry’s research shows food matrix — the physical structure — drives how much you eat, not whether it’s technically “ultra-processed.” Soft, easy-to-eat foods disappear fast. Foods that require chewing slow you down.
Example: Steel-cut oats vs instant oats
Clinical trials show a clear hierarchy:
- Steel-cut oats cause the lowest blood sugar spike
- Rolled oats are moderate
- Instant oats are almost like eating sugar
Same ingredient. Different structure. Completely different metabolic response.
The structure is everything.
When food keeps its whole form — when you have to chew it, when it takes time to break down — your body registers fullness. You eat less. Blood sugar stays steadier. Hormones behave.
When food’s been milled, puffed, extruded, or turned into powder, it bypasses your natural satiety signals. You can eat a shocking amount before your brain catches up.
That’s why organic Coco Pops are still Coco Pops. Slightly fewer pesticides, yes. Still 40% sugar. Still ultra-processed rubbish. “Organic” doesn’t make junk food healthy.
How to Shop: Perimeter vs Middle Aisles
Supermarkets are designed to make you buy UPF. Real food lives on the edges — vegetables, fruit, meat, fish, dairy, eggs. Walk the perimeter, fill your trolley, done.
The middle aisles? That’s where the 20-25% high-risk stuff lives. Forty meters of breakfast cereals. Entire aisles of biscuits, crisps, fizzy drinks. But there’s also tinned beans, oats, frozen veg, tinned fish.
Middle aisles aren’t forbidden. Just selective.
My approach:
- Shop the perimeter first — meat, veg, eggs, dairy
- Go to middle aisles for specific things: tinned fish, oats, frozen berries
- Know what I’m there for
- Not browsing the cereal aisle
Focus on structure: is it whole or is it engineered? Tinned chickpeas = whole. Ready meal with 40 ingredients = engineered. That’s your filter.
The Practical Filter: Reading Ingredient Lists
Here’s the rule that cuts through confusion: read ingredient lists.
If it’s got 5 ingredients you recognise, probably fine. If it’s got 30 ingredients and three of them sound like a chemistry experiment, put it back.
Examples:
✅ Tinned tomatoes (3 ingredients: tomatoes, salt, citric acid) — Fine
❌ Tomato pasta sauce (15 ingredients including sugar, modified starch, stabilisers) — High-risk
✅ Natural yogurt (milk, live cultures) — Fine
❌ Fruit yogurt (milk, sugar, modified starch, flavourings, colourings, stabilisers) — High-risk
✅ Whole grain bread (flour, water, yeast, salt, seeds) — Fine
❌ Supermarket sandwich (bread with 20 ingredients, filling with 15 more) — High-risk
The 10% Rule still applies. If 90% of your food is whole or minimally processed, that 10% won’t derail you. But if you’re living in the middle aisles, buying the brightly coloured boxes with cartoon characters, you’re in that 20-25% high-risk zone.
🎯 Key Takeaways
- Only 20-25% of UK supermarket food is genuinely high-risk — Not 65%, according to King’s College research by Professor Sarah Berry
- Food matrix matters more than NOVA category — Steel-cut oats vs instant oats proves structure determines metabolic response
- Shop the perimeter first, middle aisles selectively — Real food lives on edges; only 20-25% of middle aisles is problematic
Ready to Cut Through the UPF Confusion?
The panic around processed food makes healthy eating feel impossible. But when you know only 20-25% of supermarkets is genuinely high-risk, you can relax and make smarter choices.
If you’re navigating post-fast glucose spikes, refeeds, or any other metabolic surprises, the 14-Day Rhythm Reset walks you through the body’s repair logic — not just the textbook version.
👉 Get the 14-Day Rhythm Reset Guide (free)
💪 Want ongoing support? Join Rhythm Club for £30/month (includes FREE app access, community, and weekly accountability calls)
🔽 Read the Video Transcript
Someone asked: “Is all processed food bad? Do I have to avoid everything in the middle aisles?”
Here’s what Professor Sarah Berry — King’s College London, ZOE research — says: it’s not 65% of processed food we should worry about. It’s actually only 20 to 25% of what’s on UK supermarket shelves that’s processed in a way that’s genuinely bad for health.
The rest? Ranges from fine to actively beneficial.
This matters because the UPF panic has people terrified of tinned beans, frozen vegetables, whole grain bread. But Professor Berry’s research shows not all processing is equal.
Some processing preserves nutrients. Some destroys food matrix. The NOVA classification system lumps them together, which creates unnecessary fear and makes healthy eating feel impossible.
Professor Sarah Berry runs the ZOE research studies — thousands of participants, continuous glucose monitors, blood tests, the works. Her finding: only 20 to 25% of supermarket food is high-risk ultra-processed. That’s the stuff with long ingredient lists, additives you can’t pronounce, engineered to be hyper-palatable.
The other 75 to 80%? Includes minimally processed foods that are perfectly healthy. Tinned tomatoes. Frozen spinach. Whole grain bread with 4 ingredients. Natural yogurt. Even some packaged foods with short, recognizable ingredient lists.
Here’s what actually matters: food texture determines overconsumption more than NOVA classification.
Professor Berry explains it’s the food matrix — the physical structure — that drives how much you eat, not whether it’s technically “ultra-processed.” Soft, easy-to-eat foods disappear fast. Foods that require chewing slow you down.
Example: Steel-cut oats vs instant oats. Clinical trials show a clear hierarchy. Steel-cut oats cause the lowest blood sugar spike. Rolled oats are moderate. Instant oats? Almost like sugar. Same ingredient. Different structure. Completely different metabolic response.
The structure is everything.
Supermarkets are designed to make you buy UPF. Real food lives on the edges — vegetables, fruit, meat, fish, dairy, eggs. Walk the perimeter, fill your trolley, done.
The middle aisles? That’s where the 20-25% high-risk stuff lives. Forty meters of breakfast cereals, entire aisles of biscuits, crisps, fizzy drinks. But there’s also tinned beans, oats, frozen veg, tinned fish. Middle aisles aren’t forbidden. Just selective.
I shop the perimeter first — meat, veg, eggs, dairy. Then I go to middle aisles for specific things: tinned fish, oats, frozen berries. I know what I’m there for. I’m not browsing the cereal aisle.
And remember: organic Coco Pops = Coco Pops. Slightly fewer pesticides, still 40% sugar, still ultra-processed rubbish. “Organic” doesn’t make junk food healthy.
Focus on structure: is it whole or is it engineered? Tinned chickpeas = whole. Ready meal with 40 ingredients = engineered. That’s your filter.
Here’s the practical rule: read ingredient lists. If it’s got 5 ingredients you recognize, probably fine. If it’s got 30 ingredients and three of them sound like a chemistry experiment, put it back.
Tinned tomatoes with 3 ingredients? Fine. Tomato sauce with 15 ingredients including sugar and stabilizers? That’s edging toward high-risk.
The 10% Rule still applies. If 90% of your food is whole or minimally processed, that 10% won’t derail you. But if you’re living in the middle aisles, buying the brightly colored boxes with cartoon characters, you’re in that 20-25% high-risk zone.
Bottom line: not all processed food is bad. Only 20 to 25% of supermarket food is genuinely high-risk. Focus on food matrix — whole structure, short ingredient lists, foods that require chewing.
You’re not trapped.
Free 14-Day Rhythm Reset Guide in the description includes shopping guidance — what to buy, what to skip, no stress.
This is educational content based on research and my experience. Not medical advice. Focus on whole foods as your baseline, and speak to your GP if you have specific health concerns.
⚠️ Important: This is educational content based on evidence and personal experience. It is not medical advice. Speak to your GP before making changes to your fasting pattern, diet, or medication.
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