A major new study from the University of Sydney has found that countries where people eat more plant-based proteins—such as chickpeas, lentils, tofu, and peas—tend to have longer adult life expectancies.
The research, published in Nature Communications, analyzed food and population data from 101 countries over nearly 60 years and revealed a clear link between diets rich in plant proteins and better long-term health outcomes.
Led by Dr. Alistair Senior and Ph.D. candidate Caitlin Andrews from the university’s Charles Perkins Center, the study explored how the types of proteins people consume influence their life expectancy.
The researchers looked at data from 1961 to 2018, including how much food was available in each country and the levels of calories, proteins, and fats in the national diets. Importantly, the data was adjusted for differences in wealth and population size to ensure fair comparisons across countries.
The findings showed a complex picture: in young children, especially under the age of five, countries that had more animal-based proteins like meat, eggs, and dairy saw lower infant mortality rates. This supports past research showing the importance of high-energy, nutrient-rich animal products for early growth and development.
However, the trend reversed for adults. In older populations, countries that consumed more plant-based proteins tended to have higher life expectancies. For example, India, where diets are traditionally higher in plant-based foods, had better long-term survival outcomes compared to countries like the United States, where animal protein is more dominant in the diet.
The health benefits of plant-based proteins are well supported by previous research. Diets rich in legumes, nuts, and whole grains have been linked to lower risks of heart disease, type 2 diabetes, and some cancers. In contrast, diets high in processed meats have been associated with higher rates of chronic disease and earlier death.
These patterns are also reflected in real-world longevity hotspots. Populations in places like Okinawa in Japan, Ikaria in Greece, and Loma Linda in California—known for their high number of people living into their 90s and 100s—eat mostly plant-based diets with limited animal products.
Dr. Senior emphasized that this new evidence matters not just for individual health, but also for environmental concerns. As wealthier countries work to reduce carbon emissions and the environmental impact of food production, understanding the health effects of different protein sources becomes more important.
“Protein is essential to our diet, but the source matters,” Dr. Senior said. “Knowing that plant-based proteins are linked to longer life expectancy helps guide both personal dietary choices and public health policy, especially as we aim for diets that are good for both people and the planet.”
In short, this global study adds to growing evidence that plant-based proteins may not only reduce our risk of disease but also help us live longer—and more sustainably.
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The research findings can be found in Nature Communications.
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