Ultra-Processed Food Isn't Just Unhealthy – I Now Believe It's as Dangerous as Smoking
René Caruso is a Metabolic Health and Longevity Strategist, author, and founder of REPO FIT Inc., with over 30 years of experience helping individuals and clinical teams achieve sustainable wellness. Drawing from both professional expertise and her personal journey, she empowers clients to restore metabolic function, optimize energy, and build lasting health free from shame or quick fixes.
For years, my honest answer to anyone who asked about ultra-processed food was: everything in moderation. A cereal bar here, a diet soda there, a supermarket loaf when life is busy, a little wouldn't hurt anyone. I no longer believe that. The more I've read of the research behind ultra-processed food, and the more I've sat with the work of physician and researcher Dr. Chris van Tulleken, the more convinced I've become that we are looking at a public health threat on the same scale as tobacco. This isn't a piece about cutting out treats. It's about understanding what has actually happened to our food supply, why it is making us sick, and why I think the comparison to smoking is no longer a stretch.
What is ultra-processed food, really?
Ultra-processed food, or UPF, is not just food that has been processed. Humans have processed food for as long as we've had knives, fire, and salt, and that kind of processing–cooking, fermenting, grinding, curing–is part of what makes us human. UPF is different: industrially formulated products built from fractionated crops such as corn, soy, wheat, and rice, stripped down into starches, oils, and protein isolates, then reassembled with additives into something that looks, tastes, and is marketed like food.
The concept was developed in Brazil by the epidemiologist Carlos Monteiro and his team, whose Nova food classification system is now used by researchers at institutions including the World Health Organization (WHO), the United Nations Children's Fund (UNICEF), Harvard, and Oxford. Van Tulleken offers a simple rule of thumb drawn from that work: if a product is wrapped in plastic and contains at least one ingredient you would not find in a typical home kitchen, it is almost certainly ultra-processed.
Why I used to say a little was fine, and what changed my mind
My old position was rooted in a fair idea: obsessing over any single food is its own kind of unhealthy relationship with eating, and moralizing about what people put in their mouths rarely helps anyone. I still believe that. What I no longer believe is that ultra-processed food is simply a more extreme version of ordinary treats, best handled in moderation like a slice of cake at a birthday party.
What shifted my thinking was learning how deliberately these products are engineered, and how much of the disease burden connected to them has nothing to do with the willpower of the people eating them. Van Tulleken, an infectious disease doctor and academic at University College London (UCL), has spent the past several years building the public case that diet-related disease is what he calls commerciogenic: substantially driven by commercial and financial incentives, not personal failure. Once I understood the scale of that engineering, moderation started to feel like the wrong frame entirely.
The science: Your body can't always tell the difference
The most striking evidence I've come across is a randomized controlled trial led by Kevin Hall, a senior investigator at the United States National Institutes of Health (NIH). Twenty adults were housed for a month and fed, in random order, two weeks of an ultra-processed diet and two weeks of a minimally processed diet. Crucially, both diets were matched for calories, sugar, salt, fat, and fiber, and participants rated them as equally enjoyable. Despite that matching, people ate roughly 500 more calories a day on the ultra-processed diet and gained close to a kilogram in two weeks, while the unprocessed diet produced weight loss over the same period.
Van Tulleken also points to a classic experiment from Bristol in which people ate apples in different physical forms: whole, chopped, pureed, pureed with the fiber removed, and pureed with the fiber added back. Whole apples produced the most fullness and the gentlest blood sugar response. Even adding the fiber back into the puree didn't recreate the effect of eating an intact apple. The structure of food, not just its nutrient content, appears to change how our bodies respond.
His shorthand for the mechanism is that ultra-processed food tells the body lies: sweetness without the sugar the tongue expects, a fatty mouthfeel without meaningful fat, a savory hit from flavor compounds without the protein that savory taste is supposed to signal. When taste and nutrition stop matching up, the argument goes, our normal appetite regulation struggles to do its job.
Beyond the scale: The wider disease picture
Weight gain is the smallest part of the story. Van Tulleken, drawing on a review of the evidence conducted with his UCL colleague Sam Dicken, points to associations between UPF intake and cardiovascular disease, several cancers, type 2 diabetes, high blood pressure, fatty liver disease, inflammatory bowel disease, anxiety, depression, dementia and earlier death. He is careful with his language here, and so am I: this is strongly associated evidence from observational research, not proof that any single ingredient causes any single disease. But the breadth of that list is exactly why I now think moderation is the wrong lens. We don't tell people a little tobacco smoke is fine because the data is merely associational.
Why exercise and willpower were never the whole answer
One of the more humbling pieces of research in this space comes from the anthropologist Herman Pontzer, who measured energy expenditure among the Hadza, a hunter-gatherer community in Tanzania who walk, dig, and hunt for hours every day. Despite that activity, their total daily energy expenditure was statistically indistinguishable from that of sedentary adults in the United States and Europe. Pontzer explains that the body operates on something closer to a fixed energy budget, reallocating energy rather than simply burning more when activity increases.
Van Tulleken uses this, along with a well-known reanalysis of the marshmallow test that found much of its predictive power disappeared once researchers accounted for a child's socioeconomic background, to make a point I found genuinely persuasive: exercise is medicine, and self-discipline is real, but neither one explains why obesity rates rose in lockstep across every demographic group starting in the 1970s. Something in the environment changed. For him, and now for me, that something is what ended up on supermarket shelves.
The tobacco comparison
This is the part of the argument that moved me from a little is fine to genuinely alarmed. Van Tulleken draws a direct parallel between the food industry today and the tobacco industry of several decades ago: a small number of highly financialized companies, answerable to pension funds and institutional investors who expect continual growth, producing a product engineered for repeat consumption, while funding much of the research and many of the nutrition organizations that the public relies on for guidance.
He has documented executives at major food companies who tried to shift their portfolios away from UPF and were subsequently replaced, and research from the London School of Hygiene and Tropical Medicine tracing how beverage industry funding shaped decades of public messaging around exercise and energy balance. None of this required a single evil actor. It required an industry structurally committed to growth, selling a product shown to override normal appetite regulation. That is close enough to the tobacco playbook that I no longer think the comparison is hyperbole.
To be fair to the counterargument, and to van Tulleken's own caveats, he does not call for banning ultra-processed food, and he is wary of broad taxation, precisely because lower-income households currently depend on it the most. Poverty, he argues, is one of the deepest causes of diet-related disease, and policies that punish people for eating what is cheapest and most available would make the problem worse, not better. My own stance has hardened around the product and the system that manufactures it, not around the people who eat it.
What I'm doing differently
I'm not interested in perfection, and neither is van Tulleken. Even his own children eat some UPF, because food is social and he doesn't want them isolated from their friends over it. What I have changed is my default. I read ingredient lists before I buy. I treat bread, cereal, and snack bars from health-branded companies with the same scrutiny as obvious junk food, because some of the most deceptively marketed products on the shelf are UPF in a wholesome package. I cook more of what I can from ingredients I recognize, and I've stopped thinking of that as a lifestyle upgrade and started thinking of it as basic self-preservation.
I've also stopped framing this as an individual failing when it doesn't work out. If real food costs more time, money, and kitchen equipment than the products competing with it on the shelf, then access to real food is a structural issue as much as a personal one, especially for people without the time or resources to cook from scratch every night.
Seven ways to start eating more real food
None of this requires a personality overhaul overnight. Here's where I'd start.
Read the ingredient list before the nutrition label: Calories, fat and sugar counts can look reassuring on a product that is still built almost entirely from fractionated starches, oils and additives. Van Tulleken's rule of thumb still works: if it's wrapped in plastic and contains something you wouldn't keep in your own kitchen, treat it as ultra-processed, regardless of what the front of the pack claims.
Be most suspicious of the health halo: Products marketed as natural, organic, or protein-packed are often just as ultra-processed as the snack aisle staples they're positioned against. A strawberry cereal bar with five percent actual strawberry, or an artisan-looking loaf held together with industrial emulsifiers, deserves the same scrutiny as anything else on the shelf.
Cook one more meal a week from ingredients you recognize: You don't need to overhaul every meal. Pick one meal you currently buy ready-made and swap it for something built from whole ingredients. Small, repeatable changes are what actually stick, and they give you a direct comparison of how each version makes you feel.
Batch cook to make real food genuinely convenient: Part of what makes UPF so hard to compete with is convenience. Cook larger quantities of grains, beans, or a simple sauce once and portion it out, so real food is as quick to grab on a busy evening as anything from a box.
Keep a short list of easy, real food staples on hand: Eggs, oats, tinned beans, frozen vegetables, rice, and a few proteins you like cooking with go a long way. Having reliable staples in the house removes the decision fatigue that so often ends in a delivery order or a packet meal.
Push for better food where you don't control the menu: Van Tulleken's strongest policy recommendation is to improve the food served in schools, hospitals, and workplaces, because that's where many people have the least choice. If you sit on a school board, manage a workplace cafeteria, or simply have a voice in one of these settings, raising the standard of what's served there matters more than any individual's grocery list.
Leave room for food to still be social and joyful: Even van Tulleken's own children eat ultra-processed food sometimes, because food is how families and friends connect, and rigid prohibition can do its own kind of harm. The goal isn't a perfect diet. It's shifting your default so that, most of the time, real food is the easy choice rather than the exception.
Start rethinking what's on your plate
I'm not asking you to swear off every packaged product tomorrow. I'm asking you to read the label the way you'd read a cigarette pack: with a clear eye on what the product is actually built from, and why. Start with one meal a day built from food you'd recognize in a kitchen. Notice how you feel. Then decide for yourself whether a little ultra-processed food really is fine, or whether, like me, you start to see it differently.
If you're ready to take a closer look at how the food you eat is shaping your health, and want support building habits that actually stick, book a coaching call today. Let's work through what real, sustainable change looks like for you.
Read more from René Caruso
René Caruso, Metabolic Health Specialist, Peptide Consultant
René Caruso is a Metabolic Health and Longevity Strategist, speaker, author, and peptide-certified consultant with over 30 years of experience in nutrition, metabolic health, and behavior change. After overcoming decades of disordered eating and rebuilding her own relationship with food, René has dedicated her work to helping others restore energy, improve body composition, and find peace with food. She works with individuals, clinics, and wellness providers to translate complex health strategies into practical, sustainable programs that work in real life. Her mission is to help people cut through the noise, understand their body, and create health that finally feels doable.
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