You probably think you know why you're gaining weight. It's the carbs, right? Or the sugar. Maybe you just lack willpower when that bag of chips is sitting on the counter staring you down.
Chris van Tulleken says you're wrong.
In his book Ultra Processed People, van Tulleken—an infectious disease doctor and BBC presenter—argues that our struggle with food has almost nothing to do with personal failure. It has everything to do with the fact that we aren't actually eating food anymore. We’re eating industrially produced edible substances. These things were designed by scientists to bypass our internal "I'm full" signals.
It's kind of terrifying.
What the Ultra Processed People Book is Actually Saying
The core of the book revolves around a specific acronym: UPF. Ultra-Processed Food. It's a term coined by Carlos Monteiro and his team at the University of São Paulo. They developed the NOVA scale, which categorizes food not by nutrients, but by how much it’s been messed with in a factory.
Group 1 is the real stuff. Apples. Steak. Eggs. Group 4 is the disaster zone.
UPF isn't just "junk food." It's more insidious. We're talking about bread that stays soft for three weeks because it's packed with emulsifiers. We're talking about "healthy" fruit yogurts that contain thickeners and flavors instead of actual fruit pieces. If the ingredient list looks like a chemistry experiment or contains things you wouldn't find in a normal kitchen—like xanthan gum, soy lecithin, or high-fructose corn syrup—it’s UPF.
Van Tulleken didn't just write about this; he lived it. He conducted a month-long experiment where 80% of his calories came from UPF. It’s the "Super Size Me" for the modern era, but more scientific. He felt terrible. His brain chemistry changed. His hormones that regulate hunger, like leptin and ghrelin, basically went haywire.
He found that UPF makes you eat more. A lot more. About 500 extra calories a day compared to eating whole foods. And it's not because you're greedy. It's because the food is literally predigested by machines. It slides down your throat so fast your brain doesn't even realize you've swallowed it.
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The Emulsifier Problem
Most of us ignore ingredients like polysorbate 80 or carboxymethylcellulose. We shouldn't.
Van Tulleken highlights research showing these chemicals act like detergents in your gut. They wear down the mucus lining of your intestines. When that lining thins out, bacteria can get closer to your gut wall, triggering inflammation. This isn't some fringe theory. It’s a documented mechanism linked to inflammatory bowel disease and metabolic syndrome.
The Economics of Disgust
Why is this stuff everywhere? Money.
Companies aren't trying to kill us. They're just trying to satisfy shareholders. To do that, they need to make food as cheap as possible and as shelf-stable as possible. Real food rots. Real food is expensive to ship. UPF is indestructible. It’s made from the leftovers of industrial agriculture—mostly soy, corn, and wheat—that have been broken down into molecules and reassembled with salt, sugar, and fat.
It's essentially a "pre-chewed" bolus of energy.
One of the most striking points in Ultra Processed People is the discussion of "food deserts" and poverty. For many, UPF is the only affordable option. It’s a systemic trap. If you’re working three jobs and have five dollars to feed your kids, a pack of frozen breaded chicken nuggets and a loaf of white bread is a rational choice. The industry knows this. They target the most vulnerable populations with aggressive marketing.
It's Not a "Lifestyle Choice"
We love to blame individuals.
The book argues that the "balanced diet" and "everything in moderation" mantras are basically corporate propaganda. How can you have moderation with something specifically engineered to be addictive? You can't. You wouldn't tell a smoker to just "smoke in moderation" if the cigarettes were designed to be impossible to put down.
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Van Tulleken is quite blunt about the fact that exercise can't fix a UPF-heavy diet. You cannot outrun a diet of emulsifiers and modified starches. The math doesn't work. The biological signals are too strong.
He also touches on the environmental impact. Monocultures of soy and palm oil—the building blocks of UPF—are destroying biodiversity. We are trading the health of the planet and our own bodies for cheap, convenient calories that don't even taste that good once you stop and really think about the texture.
What People Get Wrong About the Book
Some critics say van Tulleken is being an elitist. They say he wants everyone to spend four hours a day cooking organic kale.
Honestly, that's a misreading.
He’s actually very sympathetic to the people eating this stuff. He doesn't judge the consumer; he judges the system. He acknowledges that for many, quitting UPF is nearly impossible right now. The book is a call for regulation, not a lecture on "clean eating." He wants warning labels on packages. He wants an end to predatory marketing to children. He wants us to see UPF for what it is: an addictive, industrial product.
How to Actually Apply This
If you've read the ultra processed people book, you're probably wondering how to survive in a world that is 60% factory foam.
It’s hard.
Start by reading the back of the pack, not the front. The front of the pack is where the lies live. "High in fiber," "Natural flavors," "Heart healthy"—ignore it all. Look at the ingredients. If there is an ingredient you don't have in your pantry, it's likely a UPF.
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- Switch your bread. Most supermarket bread is UPF. Look for sourdough that only has flour, water, and salt.
- Ditch the "healthy" bars. Most protein and granola bars are just candy bars with better marketing and more soy protein isolate.
- Watch the milk alternatives. Many oat and almond milks are full of gums and stabilizers to give them that creamy mouthfeel.
- Cook simply. You don't need to be a chef. An egg on a piece of real toast is better than a "meal replacement" shake any day of the week.
The goal isn't perfection. That leads to orthorexia. The goal is awareness. Once you start noticing the weird, oily film that some UPFs leave on the roof of your mouth, or the way you feel "hungry-full" after a fast-food meal, the spell starts to break.
Van Tulleken suggests a radical approach: keep eating the UPF while you read the book. Don't try to quit immediately. Just pay attention to how it makes you feel. Usually, by the time people finish the last chapter, they find the stuff repulsive.
Moving Forward Without the Fear
We have to live in the real world. You’re going to eat a Pringle occasionally. You’re going to have a slice of birthday cake. The point isn't to live in fear of a chemical. The point is to recognize that our current food system is a massive, uncontrolled experiment on human biology.
We are the first generations in history to eat this way. The results are in: soaring rates of obesity, type 2 diabetes, and childhood metabolic disease.
The shift back to real food isn't just about weight loss. It's about reclaiming our relationship with what we put in our bodies. It’s about eating things that were grown, not manufactured.
Next Steps for a UPF-Free Life:
- Audit your pantry by checking for "industrial" ingredients like maltodextrin, lecithin, and "flavorings."
- Focus on "single-ingredient" foods for at least two meals a day—things like nuts, fruit, eggs, or vegetables.
- Support local bakeries or brands that use traditional fermentation instead of chemical raising agents.
- Advocate for better food labeling in your community; change happens when the public demands transparency.
The transition isn't easy, but your gut—and your brain—will thank you once the inflammation starts to clear and your natural hunger signals finally return to normal.