Ultra-processed foods and longevity: what 'ultra-processed' actually means for how you age

There’s a number that stopped me cold the first time I read it: in the UK and US, ultra-processed foods make up more than half of the average adult’s daily calories. Over half. For teenagers it’s closer to two-thirds. So the average diet in two of the wealthiest countries on earth is now mostly things that didn’t exist a century ago and that no grandmother would recognise as food.

I find this genuinely fascinating, and a little bit grim, which is roughly my relationship with most nutrition research. Because the term “ultra-processed” gets thrown around a lot — usually by someone selling you a powder that is, ironically, ultra-processed — and most people have no idea what it actually means. So let’s sort that out first, then look at what the research says about whether it matters for how long, and how well, you live.

What “ultra-processed” actually means

The word “processed” is doing a lot of unfair work. Freezing peas is processing. So is fermenting milk into yoghurt, or pressing olives into oil. None of that is the problem. The useful framework here is the NOVA classification, developed by Carlos Monteiro and colleagues at the University of São Paulo, which sorts foods into four groups by how and why they’re processed rather than by nutrients.

• Group 1 — unprocessed or minimally processed: vegetables, fruit, eggs, plain milk, fresh meat, dried legumes, bagged spinach. Things that are basically still the food they started as.
• Group 2 — culinary ingredients: oils, butter, salt, sugar, honey. Things you cook with, not things you eat alone.
• Group 3 — processed foods: tinned beans, fresh bread, cheese, smoked fish, tinned tomatoes. Group 1 foods preserved with group 2 ingredients. Recognisable, short ingredient lists.
• Group 4 — ultra-processed foods (UPFs): industrial formulations made mostly from substances extracted from foods — refined oils, starches, sugars, protein isolates — plus additives you’d never keep in a kitchen: emulsifiers, stabilisers, artificial flavours, colours, non-sugar sweeteners.

The practical test: look at the ingredient list. If it’s long, and you couldn’t buy half the ingredients in a normal shop, and the product is engineered to sit on a shelf for a year and taste irresistible — that’s group 4. Soft drinks, packaged snacks, most mass-produced bread, breakfast cereals, reconstituted “chicken” shapes, instant noodles, flavoured yoghurts, protein bars, the lot. Tinned tomatoes are fine. The diet ready meal marketed at you for being “clean” is, very often, not.

This is the bit people get wrong. UPF isn’t about salt, sugar, and fat content. It’s about industrial formulation. A homemade cake with butter and sugar is group 3-ish; a shelf-stable packaged cake with mono- and diglycerides and a colour code is group 4. Same indulgence, different category.

What the research actually shows

Here’s where it gets uncomfortable, because the evidence has piled up faster than almost any other area of nutrition science in the last few years.

The headline study is a 2024 umbrella review published in The BMJ by Lane and colleagues, which pooled 45 separate meta-analyses covering nearly 10 million people. Higher ultra-processed food intake was associated with roughly a 21% higher risk of all-cause mortality, plus higher risk of cardiovascular death, type 2 diabetes, anxiety, depression, and adverse sleep outcomes. An umbrella review is a review of reviews — it’s about as high up the evidence pyramid as observational data gets.

Drill into the individual cohorts and the picture is consistent. The French NutriNet-Santé study (Schnabel et al., JAMA Internal Medicine, 2019) followed 44,551 adults and found that each 10% increase in the proportion of UPF in the diet was associated with a 14% higher risk of all-cause mortality. The Spanish SUN cohort (Rico-Campà et al., The BMJ, 2019) followed nearly 20,000 university graduates and found that those eating more than four servings of UPF a day had a 62% higher risk of death over the follow-up compared with those eating fewer than two. The Italian Moli-sani study (Bonaccio et al., American Journal of Clinical Nutrition, 2021) found higher UPF intake linked to both cardiovascular and all-cause mortality, partly explained by sugar but not entirely.

And in 2024, a 30-year analysis of the big US cohorts — the Nurses’ Health Study and the Health Professionals Follow-up Study (Fang et al., The BMJ) — tracked over 110,000 people and found a modest but real association between higher UPF intake and mortality, with the strongest signals coming from processed meats and sugary drinks specifically. That detail matters: not all UPFs are equal, and the worst offenders are fairly predictable.

I’ll be honest about the caveat, because pretending otherwise would be the kind of thing Tessa-who-finds-wellness-culture-absurd would mock. These are observational studies. People who eat a lot of UPF also tend to smoke more, move less, sleep worse, and earn less — and researchers can only adjust for the confounders they measure. Association is not causation. But when this many large, independent cohorts on three continents all point the same direction, and there’s a plausible mechanism, the cautious read isn’t “ignore it.” It’s “the burden of proof has shifted.”

The experiment that changed the conversation

The single most interesting study in this whole area isn’t a cohort at all. It’s a small, tightly controlled trial that gets at the question everyone actually wants answered: is it the processing, or just the junk?

In 2019, Kevin Hall and colleagues at the US National Institutes of Health published a randomised controlled metabolic-ward study in Cell Metabolism. Twenty adults lived in a research facility and were fed, in random order, two weeks of an ultra-processed diet and two weeks of an unprocessed diet. Crucially, the two diets were matched for calories presented, sugar, fat, fibre, sodium, and macronutrients. Participants could eat as much or as little as they wanted at each meal.

On the ultra-processed diet, people ate about 500 more calories a day and gained weight. On the unprocessed diet, they ate less and lost weight. Same nutrients on paper. The only difference was the processing.

Why? A few likely reasons. UPFs are more energy-dense — more calories per bite. They’re softer and eaten faster, which means you’ve swallowed more before your gut hormones get the chance to signal fullness. They tend to be low in protein, and there’s a decent theory (the “protein leverage hypothesis,” from Simpson and Raubenheimer) that we keep eating until we hit a protein target — so low-protein food drives overeating of everything else. And they’re literally engineered toward a “bliss point” of salt, sugar, and fat that’s hard to stop eating.

This is the closest thing we have to causal evidence, and it suggests the processing itself — not just the nutrient label — drives overconsumption. Which is exactly what the food industry would prefer you didn’t think about.

How UPFs plausibly accelerate aging

For longevity specifically, the calorie story is only half of it. The other half is the mechanisms that overlap with the core pathways of biological aging.

Chronic inflammation. Diets high in UPF are consistently associated with higher levels of inflammatory markers like C-reactive protein. Low-grade, persistent inflammation — sometimes called “inflammaging” — is one of the better-established drivers of age-related disease. I’ve written more about that in the piece on inflammaging and chronic inflammation, but the short version is: a diet that keeps your immune system mildly switched on for decades is not doing your cardiovascular system any favours.

Blood-sugar volatility. Most UPFs are refined, low-fibre, and rapidly digested, which means sharper glucose spikes and crashes. Over time, repeated spikes contribute to insulin resistance and the glycation of proteins — a literal stiffening and browning of tissue that’s part of how bodies age. This is the territory I covered in blood glucose and longevity; UPFs are basically a delivery system for the problem.

A disrupted gut microbiome. Emulsifiers and additives common in UPFs have been shown in animal and some human studies to thin the protective mucus layer of the gut and shift the microbial community toward a more inflammatory profile. Combined with the low fibre content — and fibre is the main thing your gut bacteria actually eat — UPF-heavy diets tend to starve the very microbes associated with healthy aging. More on that ecosystem in the gut microbiome and longevity.

Telomere wear. This one’s more tentative, but a 2020 cross-sectional analysis of the Spanish SUN cohort (Alonso-Pedrero et al., American Journal of Clinical Nutrition) found that people eating the most UPF — more than three servings a day — had nearly twice the odds of having short telomeres compared with those eating the least. Telomeres are the protective caps on chromosomes that shorten as cells age. It’s a correlation in a single elderly cohort, not a verdict, but it’s consistent with everything else.

None of these mechanisms is exotic. They’re the same pathways — inflammation, glucose dysregulation, microbiome health — that show up in nearly every longevity conversation. UPFs just happen to push on all of them at once.

What this looks like in real life

Right, so this is the part where a lesser blog tells you to “eliminate all processed foods” and “shop only the perimeter of the supermarket,” and you nod and then buy crisps on the way home because real life exists. I’m not going to do that, partly because it doesn’t work and partly because I had a packet of crisps last week and they were excellent.

The research itself points to a kinder approach: it’s a dose-response relationship. More is worse, less is better, and there’s no cliff edge you have to get below. The biggest gains come from moving off the top of the scale — from “most of my diet” toward “some of my diet” — not from chasing zero.

Here’s what’s actually worked for me and the people I nag about this:

• Fix drinks first. Sugary soft drinks and energy drinks are among the worst-implicated UPFs and the easiest to swap. Fizzy water, coffee, tea. This one change alone moves the needle.
• Demote processed meats. Sausages, bacon, deli slices, hot dogs — these came up repeatedly as the worst category in the US cohort data. They don’t have to vanish; they just shouldn’t be daily.
• Anchor meals around protein and fibre. Not because of any single magic nutrient, but because high-protein, high-fibre meals keep you full, which structurally crowds out the snacky UPF stuff. This is the core idea in the longevity diet piece and the dietary fibre one.
• Cook the boring base. You don’t need to make everything from scratch. Tinned beans, frozen veg, pre-cooked grains, plain yoghurt — these are group 1 and 3 foods, they’re cheap, and they take the pressure off. “Minimally processed” is allowed to be lazy.
• Keep the indulgences as indulgences. A real croissant from the bakery on a Sunday is a different thing from a shelf-stable pastry you eat absent-mindedly five days a week. The problem was never the occasional treat. It’s the default.

That’s it. No purity, no cult, no throwing out everything in your cupboard. Just shifting the ratio.

Common mistakes and misconceptions

“Low-fat / high-protein / keto means healthy.” Plenty of UPFs are marketed on a single nutrient — high-protein bars, low-fat puddings, keto snacks — while being thoroughly group 4. The marketing claim and the processing level are unrelated.

“Natural and organic means not ultra-processed.” Nope. Organic soft drinks, natural-flavoured snacks, plant-based reconstituted meats — many are textbook UPFs. The NOVA group is about formulation, not the provenance of the ingredients.

“It’s just calories, so I’ll just eat less of it.” The Hall trial suggests that’s harder than it sounds, because UPFs are engineered to defeat your fullness signals. Willpower versus a product designed by food scientists to be overeaten is not a fair fight.

“All processed food is the enemy.” This is the overcorrection. Tinned fish, frozen berries, plain wholemeal bread, and yoghurt are processed and completely fine. Throwing them out in a panic just makes eating well harder and more expensive, which makes you quit. Precision matters: the target is group 4, not “anything in a packet.”

Measuring and tracking it

You can’t get a clean lab number for “UPF intake” the way you can for resting heart rate. But you can track the things that move when you cut back. Blood-sugar stability is the most direct one — if your post-meal glucose is steadier, that’s UPFs leaving the building. Inflammatory markers like CRP, energy levels, and how full you feel between meals all tend to shift too. Logging what you actually eat for a week — honestly, no editing — is usually a more sobering measurement than any blood test. Most people badly underestimate their UPF share until they write it down.

This is partly why I find food logging useful even when it’s tedious: it turns a vague “I eat alright, mostly” into an actual ratio you can do something about. I’m biased, obviously — I work at Sarvita and we built tools for exactly this — but the principle holds regardless of what you use to do it. You can’t shift a ratio you’ve never looked at.

The honest summary

Ultra-processed foods are probably not poison, and a single packet of biscuits is not going to take years off your life. But the weight of the evidence — millions of people across multiple countries, plus the one tightly controlled trial that isolated processing from nutrients — says that when UPFs become the foundation of a diet rather than the occasional guest, the long-term costs are real and they run through exactly the mechanisms that age you.

The good news is that this is one of the more actionable findings in longevity. You don’t need a supplement, a gadget, or a 5am routine. You need to nudge the ratio: a bit more real food, a bit less of the engineered stuff, and no guilt about the croissant. It’s quite a low bar, actually — which, for once, is genuinely good news.