A Mostly Plant-Based Diet Prolongs Life Expectancy by 10 Years or More

|Updated Nov 1, 2022
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When it comes to eating healthy for the sake of prolonging your life, there is no time like the present to start leaning into a plant-based diet. And even going mostly plant-based can add years to your life expectancy, even if you start today. That's the message of the latest study that finds that the benefit of eating mostly plant-based, combined with other healthy habits such as regular exercise, can prolong your life expectancy by 10 years or even more, if you are strict about it and start early enough. Who wouldn't say yes to a generous extra decade of healthy time on the planet?

The study, published in the PLOS Medicine journal claims that these healthy habits in combination can prolong life expectancy by up to 10 full years. A team of researchers from Norway initiated the study to determine what foods would benefit people, especially which habits allow them to be healthy in their later lives and examined how dietary habits alter life expectancy.

The Norwegian researchers ( led by Lars T. Fadnes, Jan-Magnus Økland, Øystein A. Haaland, and Kjell Arne Johansson) used the Global Burden of Disease (GBD) study to create a digital model to examine how typical Western diets compare to the “optimal” diet on longevity and human health. The GBD study is a collection of data that predicts how different foods correlate to the likelihood of chronic and fatal diseases.

"Based on meta-analyses and data from the Global Burden of Disease study," the authors wrote, "we used life table methodology to estimate how Life Expectancy changes with sustained changes in the intake of fruits, vegetables, whole grains, refined grains, nuts, legumes, fish, eggs, milk, dairy, red meat, processed meat, and sugar-sweetened beverages."

Even going half-way toward plant-based is healthier

The researchers identified "an optimized diet and a feasibility approach diet." They defined these two approaches as this:  "An optimal diet had substantially higher intake than a typical diet of whole grains, legumes, fish, fruits, vegetables, and included a handful of nuts, while reducing red and processed meats, sugar-sweetened beverages, and refined grains. A feasibility approach diet was a midpoint between an optimal and a typical Western diet."

The "optimal" diet vs. the "feasibility approach"

The optimal diet, which is mostly plant-based foods with a little fish, had the best outcome. The largest gains would be made by eating a diet of mostly legumes, whole grains, and nuts, and eating less red meat and processed meat, they concluded.

The optimal diet is a “substantially higher intake than a typical diet of whole grains, legumes, fish, fruits, vegetables, and included a handful of nuts while reducing red and processed meats, sugar-sweetened beverages, and refined grains.”

The reduction of red and processed meat consumption is the main way that individuals can extend their life expectancy significantly, especially when these dietary habits are started earlier in life.

  • An American woman who switches from a Western diet to an optimal diet at age 20 can increase life expectancy between 10.7 and 12.3 years.
  • An American man who switches to an optimal diet at age 20 could gain even more, the researchers estimate, or between 13 and 14 years.
  • A 60-year-old who adopts the optimal diet can prolong life expectancy by 8.8 years.
  • An 80-year-old who eats the optimal diet can also see gains; it could extend life expectancy by approximately 3.4 years.
  • If you take a "feasible" approach of mostly plant-based you could gain about 5.4 years.

“A sustained dietary change may give substantial health gains for people of all ages both for optimized and feasible changes,” the study authors wrote in their conclusion. “Gains are reduced substantially with delayed initiation of changes, particularly when approaching the age of 80 years. An increase in the intake of legumes, whole grains, and nuts, and a reduction in the intake of red meat and processed meats, contributed most to these gains.”

If individuals can't or won't go fully plant-based, however, there are still significant benefits to making an effort to do what's called the “feasibility” diet, which is defined as "halfway between the Western and optimal diets."

So trying to be a little more plant-based is better than not trying at all. In other words, adopting a flexitarian diet is a healthier way to eat and is more feasible for many people who can't go fully plant-based.

A "feasible approach" can improve life expectancy by 7 percent. Since the American life expectancy is nearly 78 years, then 7 percent would be a gain of 5.4 years of extra life.

Keep your heart healthy with a plant-based diet

The Norweigan research is far from the first study to propose that plant-based eating could add years to people's lives. Last year, a study found that eating a plant-based or plant-centric diet during young adulthood (ages 18-30) could significantly lower your risk for heart disease 30 or more years later. The study took 30 years to complete, tracking the dietary habit and health status of 5,000 people between 1985 and 2018.

The heart disease study examined people who followed a plant-centric diet defined by “higher consumption of nutritionally rich plant foods and limited consumption of high‐fat meat products and less healthy plant foods." The two research studies propose that plant-based diets could in some way help people cheat death, and prolong their lifespan. While the research allows for some “feasibility” in adopting a plant-based diet and reducing meat consumption, both studies make it clear that early healthy habits will improve health for decades.

Bottom Line: To Add 10 or More Years to Life Expectancy, Eat Mostly Plant-Based

Norwegian researchers looked at the impact of food on longevity and found that eating a mostly plant-based diet of whole foods and some fish could add more than 10 to 13 years to your life expectancy. Even going partly plant-based, in an approach that the study called the "feasibility" diet, can have major benefits for longer life. The sooner you make the switch the better, but for those 60 and older who started, they saw significant gains of up to nearly 9 years in extended life expectancy. For how to start, see the Beginner's Guide to a Plant-Based Diet.

You may think iron is synonymous with meat, and while animal protein certainly has it, that doesn’t mean you can’t get enough iron if you eat a mainly plant-based diet. In fact, you can, if you know the right foods to choose and how to pair them. The daily recommendation from the National Institutes of Health (NIH) for iron intake is 18 milligrams (mg), but not all iron sources are created equal. Here’s what plant-based eaters need to know about iron and which iron-rich foods are best to help reap the benefits.

1. White Mushrooms

1 cup cooked = 3 mg iron (17% daily value (DV))\There are many reasons to eat mushrooms on the regular, but their meaty texture (try a Portobello cap as a meat replacement for a burger!) and ample protein are two of the highlights. Add them to your stir-fry, tacos, or even instead of meat in a faux Bolognese sauce.

2. Lentils

1/2 cup = 3 mg iron (17% DV)You don’t need to eat a huge serving of lentils to get a hearty dose of iron. Just a half-cup provides close to 20% of the iron you need in a day. Just like mushrooms, lentils have a meaty texture that works well in burgers, tacos, or grain bowls.

3. Potatoes

1 medium potato = 2 mg iron (11% DV)The poor potato has gotten such a bad rap. Fear of this carb-rich spud is unwarranted because it’s actually an affordable and delicious source of iron and potassium. So go ahead and have that hash, baked potato, or potato soup and leave the skin on for some added fiber.

4. Cashews

1 ounce = 2 mg iron (11% DV)Most nuts contain iron, but cashews are a standout because they have less fat than some of the other nuts. One ounce of cashews (about 16 to 18 nuts) has 160 calories, 5 grams of protein, and 13 grams of fat. Add a handful of cashews to smoothies, soups, or sauces for some extra creaminess.

5. Tofu

½ cup = 3 mg (15% DV)Not only does tofu have plenty of protein and calcium, but it’s also a good source of iron. It’s very versatile and takes on the flavor of any sauce or marinade, making it a great meat substitute.Keep in mind that you can easily get the iron you need from a plant-based diet.