Large-scale study identifies eight dietary patterns that contribute to healthy aging

We tend to use the phrase “you are what you eat” in the present tense, but science suggests we should think of it in the future tense. The diet we follow in middle age largely determines the quality of our old age. While many studies have pointed to this idea, few have had as extensive a database as the one published on Monday in Nature Medicine. The researchers tracked the diets of more than 100,000 Americans for 30 years and then assessed their health at age 70.

A diet rich in fruits, vegetables, whole grains, nuts, legumes, and low-fat dairy products was associated with better physical and mental health in old age. Conversely, higher consumption of trans fats, sodium, sugary drinks, and red or processed meats was linked to poorer health — or even death. These guidelines don’t seem particularly difficult to follow, yet the vast majority of participants didn’t adhere to them. In fact, only 9.3% experienced healthy aging. It seems that eating well is much easier in theory than in practice.

“I was also surprised by such a low percentage,” admits Marta Guasch-Ferré, a professor of epidemiology at the University of Copenhagen and one of the study’s authors. “But you also have to take into account that the participants are Americans, and there, the diet is worse and access to healthcare is more limited.” Despite these environmental differences, she insists that the study’s conclusions apply universally, as they address biological issues. In other words, if you want to know what kind of elderly person you’re going to be, just take a look at your refrigerator.

Diet is the leading behavioral risk factor for death and chronic disease worldwide, and the second-biggest risk factor (after smoking) in older adults. Understanding its relationship with healthy aging is important, especially in a rapidly aging world.

The study, however, did not account for the timing of meals or intermittent fasting, two factors Guasch acknowledges as relevant. “It’s not just what we eat that matters, but also when we eat it,” she says. But she explains that when data collection began in the 1990s, there wasn’t enough scientific evidence to support these considerations.

The researchers defined healthy aging as surviving to age 70 without developing any of the 11 major chronic diseases and without experiencing declines in cognitive function, physical function, and mental health. Better adherence to eight specific diets was associated with a greater likelihood of meeting these standards. These included the Mediterranean diet, plant-based diets, anti-inflammatory diets, and the DASH diet (designed to reduce hypertension).

“What this tells us is that there is no single way to eat healthy,” explains Guasch, “and that it is important that this diet can be culturally and socially adapted to the context of the person adopting it. In Spain, for example, it would be very difficult to ban ham, while in other countries it doesn’t require a great effort to eliminate it from the diet.”

While the study’s conclusions aren’t surprising, its scale and comprehensiveness are remarkable. “It’s a spectacular article in terms of magnitude,” says Salvador Macip, a researcher on aging, who was not involved with the study. “Never before has an epidemiological study on this topic been conducted with so many people over such a long period of time. It doesn’t tell us anything we didn’t already know, but it is an important and fairly definitive confirmation that we must promote a healthy diet to improve the health of the population.”

However, the study also underscores how difficult it is to follow this advice. The paradox is that even as evidence mounts about the harms of ultra-processed foods, their consumption continues to rise. These aren’t just foods; they’re engineered products, with sugar, salt, and fat manipulated to reach unnaturally high concentrations. This has an intense effect on the brain, leading some researchers to suggest they have addictive properties. No matter how compelling the scientific data, no paper can compete with the allure of a smash burger or an extra-cheese pizza. We know they’re unhealthy — but we keep coming back for more.

This study is less about increasing life expectancy as it is about improving quality of life. The choices we make today will shape our future. So when should we start caring about our diet if we want to feel the benefits in old age? The short answer: as soon as possible. “There are studies that show that even the diet of a pregnant mother can affect her child’s health later in life,” Guasch explains. “Diet influences our present and future health, and what you’ve eaten throughout your life will have an impact.”

That said, she offers a hopeful message: “It’s never too late to improve your diet. If you change the way you eat at 60, you’ll likely notice something at 70.” However, forming new habits — especially later in life — isn’t always easy. The best way to ensure a healthy old age is to start prioritizing it long before it arrives.

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