Live longer by eating more carbs and less meat, according to the man who unlocked secrets to living to age 100

• The longest-living people in the world eat lots of carbs and almost no meat, according to a longevity researcher.
• Author Dan Buettner helped pioneer the idea of Blue Zones, areas where people live to 100 years old.

Eating more beans and less beef could add years to your life, according to a man who literally wrote the book on how to live to 100.

Dan Buettner has spent nearly two decades researching Blue Zones, areas of the world where people live the longest, healthiest lives, including regions in Italy, Japan, Greece, and Costa Rica.

His latest book, "The Blue Zones American Kitchen: 100 Recipes to Live to 100," focuses on forgotten longevity secrets in American cooking traditions, drawing from Latin American, Indigenous, and African American cuisines.

Regardless of which country they originate from, Blue Zone diets share similar patterns, Buettner told Insider.

"It's more about the ingredients rather than the cuisine," he said.

Blue Zone diets share common patterns that are linked to major health benefits, according to Buettner. They're almost entirely based in whole foods, rely heavily on plants and complex carbohydrates and contain few, if any, processed foods and animal products.

"People look for a silver bullet 'super food' but the reality is it's the matrix of the foods we eat that come together to give us nutrients we need to thrive," he said.

Carbs like beans and grains are the foundation of a longer life, Buettner said

The closest thing to a superfood across Blue Zone diets isn't an exotic ingredient, but rather the humble bean — cheap, accessible, and one of the easiest way to improve your diet, according to Buettner.

"If you eat one cup of beans a day, you'll live longer," he said.

Beans are a rich source of fiber, linked to lower risk of cancer, heart disease, and other deadly illness. When combined with whole grains like brown rice, they make a complete protein source. A recent study suggests adding more beans and whole grains to your diet could add up to 10 years to your life.

Starchy veggies like sweet potatoes and squash round out a Blue Zones diet with vitamins and minerals like potassium and vitamin A.

Meat, sugar, and processed foods are eaten sparingly on Blue Zones diets

People living in Blue Zones also rarely eat red meat or processed foods, according to Buettner. Evidence suggests red meat is linked to colorectal cancer and heart disease, and processed foods can wreck havoc on our health.

Instead, Blue Zoners opt for plant-based protein sources like nuts and seeds, legumes, and tofu.

However, it can be challenging to cut out all processed foods, so a more realistic health goal may be limiting them to special occasions, which is how Buettner handles his own favorite sweet treat, licorice.

"I have a piece every now and then, but I don't keep it in the house," he said. "People need to be able to treat themselves."