Ultra-processed foods can make you age faster

A few months ago I tried, unsuccessfully, to create a neologism. I wrote a feature on how obesity, stress, heat waves and pollution accelerate aging, or senescence, in which I proposed that our modern world should be called the “senesogenic environment”. (I hold my hands up that this was inspired by the well-established idea that we live in an obesogenic, or “obesogenic,” environment, but no one ever invented anything in a vacuum.)

It didn’t stick. The only reference I can find to it online is my article, and a blog post about my article. I would like to try again, because I missed a major contributor to premature aging: ultra-processed foods (UPF).

For anyone who has been living under a rock for the past few years, UPFs are a class of foods that have been ultra-processed. The exact definition is disputed, but as a rule of thumb, they are prepackaged foods made in a factory from purified ingredients such as sugar, fat and protein, often chemically modified and mixed with synthetic chemicals such as dyes, emulsifiers and preservatives. They tend to be low in nutritional value – lacking in healthy nutrients such as fiber and vitamins – and steeped in fat, salt and sugar. Think cheap microwave meals, salty snacks, mass-produced bread, sugary drinks, instant noodles, ice cream, candy, baked goods, processed meats, and condiments like mayonnaise and ketchup.

Over the past 50 years, UPFs have come to make up an increasingly large proportion of the Western diet. In high-income countries, including the UK, where I live, more than half of all calories consumed are in the form of UPF. This trend has plateaued over the past decade, but globally the appetite for UPFs is still growing. And who can blame us? These foods are widely available, convenient, affordable and undeniably delicious.

It’s easy to say that it’s better to avoid UPFs, and a large body of research supports this. High UPF consumption has been linked to a long list of chronic health problems, including obesity, cancer, type 2 diabetes, cardiovascular disease, inflammatory bowel disease, fatty liver disease and kidney disease.

Not surprisingly, it also increases the risk of death from any cause. Three studies conducted in Spain, France and the United States, each following tens of thousands of people, independently found that the highest consumers of UPFs were significantly more likely to die than the most moderate consumers during the study periods.

The mechanism by which such a diverse group of foods can cause such a wide range of conditions has proven elusive. One obvious possibility is that they are obese – obesity leads to many other health problems. Other suspects are poor nutritional quality, additives, toxins generated during processing and others that may leak out of plastic packaging. Some researchers claim that the treatment itself adds an extra dollop of unhealthiness – of which more later. For now, however, there is no definitive answer.

But recent research offers a big hint: UPFs drive premature aging. In 2024, researchers analyzed the diets of 16,055 US adults aged 20 to 79 from data collected between 2003 and 2010 as part of the US National Health and Nutrition Examination Survey (NHANES). They estimated what percentage of calories each participant got from UPFs and also measured their biological age, finding that on average, the higher a person’s UPF intake, the greater the gap between their actual age and their biological age.

Each 10 percent increase in calories consumed in UPF form added an average of 0.21 years, or about two and a half months, to this discrepancy. The difference between the lowest and highest consumers of UPFs – those who consumed less than 39 percent versus more than 68 percent – ​​was 0.86 years in biological age.

Regular readers of New Scientist may feel a twinge of skepticism at this point. Biological age measurements are notoriously inaccurate: I actually poured cold water on them in the previous column. But for research like this – where people are compared against each other rather than given individual scores – that’s fine, as any systematic errors in measurement apply to all participants.

The gap doesn’t sound like much—what’s two or three months over the course of a lifetime—but the researchers point out that previous research has shown that even modest increases in biological age are linked to small but significant increases in the risk of chronic disease, disability and death over the following two years.

Other researchers have since found similar senescence-promoting effects of UPFs. Last year, for example, a team in China analyzed another data set from the UK and also discovered that people who eat a lot of UPF are biologically older and have a higher risk of death than moderate consumers.

Neither the NHANES study nor the Chinese one tracked changes in biological age over time—they only took a snapshot—but it would be an interesting next step. Even in the absence of this information, we can safely file UPFs along with obesity, stress, heat, and pollution as part of the senescent environment. In fact, their harmful effects on health may boil down to their pro-aging properties: many of the diseases associated with high UPF consumption are classic age-related conditions.

Again, this raises the question of the underlying mechanism. And again, it could be obesity, poor diet in general, toxic pollution, or a harmful mix of all three. But these don’t quite cut the mustard.

One of the ongoing debates about UPFs is whether their harmful effects are simply due to their poor nutritional quality or whether the treatment itself somehow contributes. The NHANES study emphasizes the latter view: when the researchers accounted for the nutritional quality and energy content of UPF-rich diets, they found that these alone did not account for the observed increases in biological age. “Other properties of UPF related to processing may contribute to an acceleration of biological aging processes,” they conclude.

What it is about processing that can make UPFs ultra-unhealthy remains to be elucidated. But what matters at this point is that two very large studies using different datasets from different countries have both concluded that diets high in UPF are associated with faster aging.

Take home is not difficult to train. Avoid ultra-processed foods where possible. Admittedly, that’s easier said than done—UPFs are everywhere, and in both studies, the lowest consumers still ate quite a bit. But in a world where many of the drivers of premature aging are impossible to avoid, you can at least do yourself a favor and eat real food. Oh, and do me a favor: spread the word about the senescent environment.