Over the last few years, there has been mounting evidence that eating more plants—including whole grains, fruits, vegetables, legumes, nuts and seeds—benefits health in many ways, primarily in reducing disease risk. This is partly due to plants’ effects on our microbiomes, as they provide plenty of fiber that acts as food for beneficial bacteria to thrive and multiply. A healthy microbiome has been linked with lower chronic inflammation and disease risk.

That’s not all, though. Plants also contain antioxidants, vitamins and minerals necessary for optimal health, plus macronutrients, including healthy fats, carbohydrates and protein. It’s this last nutrient that researchers in Australia wanted to take a closer look at. 

This study is a little different, as most studies we cover assess individuals’ dietary habits. This study, on the other hand, takes a broader look at the food available in different countries and how long people in those countries tend to live. The findings were published in Nature Communications. Let’s see what they found.

How Was This Study Conducted?

This study aimed to assess how the nutritional environment is associated with age-specific mortality (death) in 101 countries. Specifically, it considered animal-based protein (ABP; meat, poultry, seafood dairy and eggs) and plant-based protein (PBP) availability in these countries to see how they were associated with longevity. To do so, researchers used the geometric framework for nutrition (GFN). This framework examines undernutrition, overnutrition and nutrient amounts and compositions—that includes which macro- and micronutrients foods are made up of). 

Researchers also used food balance sheets (FBS) and life tables, which provide data on the average availability of food and nutrients at the national level and break the data down according to potential confounders that could skew results, like age, sex and the country’s level of wealth.

Using these parameters, researchers could predict the effects of ABP, PBP, fat and carbohydrate availability on a country and assess their influence on longevity at different age points, specifically children who live to age 5 and adults who live to age 60.

What Did This Study Show?

After running statistical analyses, including adjusting for confounders, researchers found that higher animal-based protein supplies were associated with enhanced survival during infancy and early childhood, independent of total calorie supplies. In other words, regardless of how much total food is available in a country, higher availability of animal protein is linked with infants and children surviving to at least 5 years old. Researchers also found that when overall protein availability was low—regardless of the type of protein—survival rates were also low in infants and children under 5.

Even so, plant-based protein was associated with better longevity in adults.  

Researchers explain that animal-based protein early in life provides complete proteins that are more easily digestible and absorbable compared to many plant-based protein sources.  In addition, compared to plants, animal-based protein also provides more fat and nutrients essential for proper growth and development in infancy and childhood. 

According to these researchers, nutrients like iron, zinc and vitamin A are often lacking in developing countries where under-5 mortality is high, and animal-based protein may be an easier provider of these nutrients. Study authors note that some infant and childhood deaths can also be attributed to maternal undernutrition and deficiencies during pregnancy, and that providing animal-based protein may more easily help fill this gap. 

This is not to say that plant protein should be neglected in infancy and childhood, since researchers note that adding energy from any protein source—animal or plant—is better than not getting enough protein overall, especially in countries where food may be more scarce. They add that plant-based diets show promise for children, as long as they are balanced and varied to provide complete amino acids and enough fat for proper development.

Interestingly, the association between animal proteins and longevity weakens as we age, with plant-based proteins becoming more positively influential, since another major finding of this study was that plant-based-rich environments were associated with improved survival later in life. 

Researchers note that the data used for this study cannot differentiate between ultra-processed foods and meats and other sources of animal protein, so they cannot state with certainty based on their study which types of animal proteins are linked to early death. With that said, previous studies link regular consumption of ultra-processed foods, processed meats and foods high in added sugar with chronic disease—including heart disease, stroke and diabetes—and dying younger. 

This study also linked higher fat availability, especially in countries where animal-based proteins were more plentiful, to dying younger. Though the researchers weren’t able to differentiate between processed meat and meat in general, one could hypothesize that some of the excessive fat consumption likely comes from ultra-processed foods and meats.

The study authors name several limitations of this study. For example, their findings are limited because they are based on national food supply data, not individual dietary intake. Because of this, they could not account for the many variables that can influence longevity. This analysis also doesn’t account for the differences between types of carbohydrates and fats, including the different types of carbs, like refined carbs, complex carbs with fiber and sugar, nor between saturated fats, polyunsaturated fats and monounsaturated fats. 

How Does This Apply to Real Life?

While it can mean different things to different people, eating plant-based doesn’t necessarily mean completely going vegan, or even vegetarian (which includes some animal products, like eggs and dairy). If you’re not ready to completely give up meat, consider increasing your intake of plants by swapping your typical meat-based recipes for more plant-forward ones. Some good sources of plant protein that are easy to start with include legumes, soy, tofu, nuts, seeds and whole grains, like quinoa and amaranth.

If you’re a big fan of meat at dinner, you could also try some recipes that stretch animal-based protein with some tasty plant protein. That’s especially easy to do when you use ground meat, like we do in our Beef & Bean Sloppy Joes, or when you make a fun grain bowl, like our Pesto Chicken Quinoa Bowls. Combining plant- and animal-based proteins is also the point of eating plans like the flexitarian diet, which balances both for filling, tasty meals that can help you ease into trying out vegan protein.

You can also make some easy swaps to add more plants to your diet. For example, instead of pizza with pepperoni, sausage, ham or beef, make it a veggie pizza. Rather than having bacon and sausage with your eggs, consider making a veggie hash—like our Sweet Potato, Broccoli & Wild Rice Hash—or something saucy like these Baked Eggs in Tomato Sauce with Kale. Now and then, swap your burger or taco with a vegetarian version, like we do in our Quinoa Veggie Burger and our Best Vegetarian Tacos.

If you’re ready to jump in for more of a full-immersion experience and want to be sure you’re getting plenty of plant-based protein, try any of our high-protein plant-based meal plans, including this weeklong plan for beginners or our 30-day plan for healthy aging. All of our meal plans are created by registered dietitians, so you know they’re balanced, nutritious and delicious. 

Most of our recipes and meal plans stay away from ultra-processed plant-based “meats,” like those that mimic the taste and texture of animal proteins like burgers, bacon and hot dogs. Ultra-processed meat, whether from animal or plant sources, usually isn’t the best choice for your health. For example, there’s evidence that eating plant-based meat products can increase your intake of calories, fat, sugar and salt, and that those who regularly rely on these products may end up with deficiencies in key nutrients, including calcium, potassium, magnesium, zinc and vitamin B12. 

What you eat is just one piece of the longevity puzzle. Plenty of habits contribute to better health, including eating a diverse diet and limiting added sugars, as well as exercising regularly, prioritizing sleep and spending time with loved ones.

The Bottom Line

This study suggests that while animal-based protein may have advantages during infancy and childhood, plant-based protein has a more positive influence later in life and may help you live longer. Eating more plant-based foods has many health advantages, including a reduced risk of cancer, heart disease and diabetes. 

You don’t have to become vegan or vegetarian to enjoy the benefits that eating more plants has to offer. Start with just one snack a day or one meal a week, and gradually go up from there. Look for easy, creative ways to add plant proteins to foods you already eat—add a handful of walnuts and chia seeds to your oatmeal, make a veggie sandwich with cheese and hummus spread on whole-grain bread or swap out the meat in your soup for protein-rich beans. Before long, you’ll realize that plants have become a regular part of your meal pattern.