The science revealing how the right diet can add a decade to your life

One of the most common inquiries directed at centenarians is: “What’s your secret?” The answers frequently focus on dietary habits. For instance, Maria Branyas Morera, recognized as the oldest person in the world at the time of her passing at age 117, attributed her longevity to consuming three yogurts daily. Jeanne Calment, who still holds the record for the longest lifespan, credited her remarkable vitality to olive oil, chocolate, and occasionally, a glass of port.

While it is true that dietary intake significantly impacts health—a fundamental requisite for longevity—it may be more insightful to consider: “What did you avoid eating?”

For instance, Lars Fadnes from the University of Bergen and his research team have established a longevity-promoting diet, informed by their analysis of the extensive Global Burden of Disease Study. This study confirmed that typical Western diets, which tend to be heavy in refined grains, added sugars, red and processed meats, and dairy products, while lacking in whole grains, fresh fruits and vegetables, nuts, and fish, are not conducive to longevity. Alarmingly, such diets are linked to 11 million premature deaths annually.

The findings suggest that a significant improvement in life expectancy can be achieved if individuals transition from unhealthy eating patterns. For example, a 20-year-old woman in the U.S. today, who follows a conventional American diet, might expect to live until age 80. However, by drastically reducing meat, sugar, dairy, and refined grains while primarily consuming whole grains, fruits, vegetables, nuts, legumes, and fish, her projected lifespan could increase to 89—a remarkable gain of nearly a decade. Similarly, switching to this balanced diet would also extend the life expectancy of a 20-year-old U.S. man from 76 to 86.

“The benefits of increasing whole grains, nuts, and legumes while reducing sugary foods and meats—particularly processed and red meats—are substantial,” states Fadnes.

Even for those who may be well past their twenties, the incentive to adopt healthier eating habits remains. Researchers found that a 60-year-old U.S. woman transitioning to a healthier diet could expect to enjoy an increase in life expectancy from 81.6 years to 89 years. Even individuals at the age of 80 could anticipate adding a few additional years to their lives.

Furthermore, Fadnes’ analysis also explored the outcomes of individuals shifting to a diet that lay midway between a typical Western diet and the optimal diet, revealing that even these individuals could expect a positive impact on their life expectancy, though not as significant as those adhering closely to the optimal dietary guidelines.

While these projections are theoretical, several practical studies substantiate the primary conclusion that diet plays a critical role in health during later stages of life. A recent investigation led by Zhaoli Dai-Keller at the University of New South Wales examined the dietary practices of numerous individuals aged 95 and older living independently across East Asia, Australia, and Western Europe. Since these participants successfully aged into their advanced years, their eating patterns warranted attention.

Minimize Salt Intake

Overall, these centenarians exhibited commendable dietary habits. Only a modest fraction consumed alcohol, while most maintained a varied and nutritious diet abundant in fruits, vegetables, white meats, fish, and legumes. A notable observation, as highlighted by Dai-Keller, is that salt intake was generally lower among these individuals. Excessive salt consumption is identified as a major contributor to cardiovascular disease, the foremost cause of mortality worldwide.

In another related study, Anne-Julie Tessier and Marta Guasch-Ferré at Harvard T.H. Chan School of Public Health conducted a reanalysis of two independent research projects involving over 105,000 individuals tracked over 30 years from 1986 as they transitioned from mid-life to early elderly years. Their objective was to identify factors associated with healthy aging, specifically reaching 70 years of age free from significant chronic diseases while retaining physical fitness and mental sharpness.

Only about 10 percent of these participants achieved that benchmark, leading researchers to ascertain that dietary choices were critical. Most of those who thrived adhered to a healthy Mediterranean-style diet throughout their middle years, while those indulging in unhealthy, fatty, and salty diets seldom experienced healthy aging.

While reaching the age of 70 in good health does not guarantee one reaches 100, it certainly creates favorable conditions.

Nonetheless, longevity encompasses more than just dietary choices; portion sizes also matter. Based on Dai-Keller’s 2024 study, a distinctive trait among centenarians is their generally lean physique. Approximately half maintained a healthy weight, and about a third were on the underweight side.

Weight Considerations and Daily Functionality

It appears that carrying extra weight is not a recipe for an extended life. Yet paradoxically, the capacity to perform daily living activities was greater among those categorized as overweight—not obese—compared to individuals of normal weight. Contrastingly, being underweight heightened the risk of functional impairment by approximately 25 percent.

This naturally leads to discussions around a popular longevity strategy: calorie restriction. Research consistently shows that one of the most reliable methods to prolong laboratory animals’ lifespans is through reducing calorie intake by at least 25 percent. However, such methods are challenging to implement for humans, and evidence supporting their effectiveness for extending human life is still inconclusive. Moreover, even if calorie restriction confers longevity benefits, it may impair individuals’ ability to carry out daily activities.

In conclusion, if you aspire to improve your odds of celebrating your 100th birthday in peak condition, the key is significantly influenced by what you choose to put on your plate.