The longest-lived people run on a high-carb diet, and it's a big part of their secret to living to 100

• Blue Zones refer to five specific places in Greece, Japan, Costa Rica, Italy, and California.
• People in these 5 zones tend to live to about 100 years old, while maintaining their good health.

Dan Buettner grew up in Minnesota during the 1960s, where the Midwesterner was fed a high-carb diet of bright yellow macaroni and cheese and sweaty red hot dogs wrapped inside flaky croissants.

"We didn't know better," he said.

But when the cyclist and storyteller started traveling around the globe, and into the homes of people in locations where elders routinely live to see their 100th birthday in good health — the world's Blue Zones, as he calls them — he noticed something distinct about the ways that they were eating.

The fare was nothing like his childhood diet of processed foods, but Buettner noticed that each Blue Zone kitchen did have a few staple ingredients in common. Like his own meal plans, they were all fairly high in carbohydrates, but these Blue Zone diets centered on carbs of a different kind.

"The four pillars of every longevity diet in the world are whole grains, greens, nuts, and beans," Buettner told Insider. "When you crunch the numbers, it's very clear that it's a 90% to 100% plant-based, very-high-carbohydrate diet. About 65% carbs, but not simple carbs like muffins and cakes — complex carbs."

Buettner's chronicled some of his favorite recipes from each of those regions in a new book, "The Blue Zones Secrets for living longer," featuring dishes and ingredients from Ikaria, Greece; Sardinia, Italy; Okinawa, Japan; Nicoya, Costa Rica; and Loma Linda, California.

People who live to 100 tend to eat lots of beans

Whether Blue Zone cuisine is from the sandy western shores of Costa Rica or industrial church kitchens in California, it is loaded with beans.

Beans are a high-carbohydrate, high-fiber food that some dieters criticize, as they're nearly impossible to eat on high-fat, low-carb eating plans like the keto diet.

"You can get very successful with a diet if you tell people they can eat what they like to eat — meat or cheese or eggs and all that," Buettner said. "I draw from people who've achieved the health outcomes we want. And I can tell you beyond a shadow of a doubt that they're eating about a cup of beans a day."

His favorite bean dish is a Greek "longevity stew," loaded with fennel, black-eyed peas, olive oil, tomato, and garlic.

The Blue Zone diet plan lines up with scientific research suggesting that people who eat more vegetables and other plants — while consuming little to no processed or red meat — are less likely to die earlier (and more likely to have healthier hearts) than people who routinely fuel up on animal products.

Blue Zoners don't go to the gym, and they rarely eat meat

In the Blue Zones, there are no banned foods. Instead, the environments people live in promote their good health almost effortlessly. There's no weighing ingredients or worrying about the amounts of carbs, protein, and fat to include in a day's meals.

Yet there are certain things that people in Blue Zones don't eat very often. Chief among the rarities are dishes high in saturated fats and sugars, including meats, dairy, and desserts.

Traditionally, people living in the Blue Zones have eaten meat about five times a month. It's usually a three- to four-ounce cut of pork, smaller than an iPhone.

When it comes to bread, Blue Zoners tend to favor fermented varieties like sourdough over plain white yeasted slices, and they pair small amounts of pasta and grains with other staple ingredients like fresh greens or beans.

"When you combine a grain and a bean, you get a whole protein," Buettner said. This means that, much like any meaty dish, a plant-based meal can feature all the essential amino acids that help the body grow and repair itself, but "without the saturated fat, without the hormones," he said.

In addition to focusing on plant-based foods, people in the Blue Zones also tend to cherish the importance of lifelong friendships, move around consistently each day (every 20 minutes or so), and live with purpose. These built-in support systems are key components of longevity too, Buettner believes, and just as important as the good food.

"We keep beating this dead horse of diets and exercise and supplements," he said. "It's Einstein's definition of insanity."

If you'd like to try the Blue Zones eating routine, Buettner suggests finding a few plant-based recipes that you really like and making it a habit to cook them for yourself again and again. None of the recipes in his books include any meat or eggs, and most shouldn't take more than 30 minutes to prepare.

"The secret to eating for 100 is to find the plant-based foods heavy with beans and grains and vegetables, and learn how to like them," Buettner said. "If you eat a Blue Zones diet religiously, it's probably worth eight to 10 extra years of life expectancy over a standard American diet. You take those years and you average them back into your life? It gives you about two hours a day to cook."

This story was originally published in 2019, when Buettner's Blue Zones Cookbook was released. It has been updated.