If you want to know the secret to living a long, healthy life, just ask Dan Buettner.

The Minnesota researcher, adventurer and National Geographic fellow will likely tell you it's really not a secret.

For more than two decades, Buettner and his colleagues have been studying longevity, traveling where people not only live longest, but also are the healthiest and happiest. He found five regions across the world — Sardinia, Italy; Okinawa, Japan; Nicoya, Costa Rica; Ikaria, Greece; and Loma Linda, Calif. — and dubbed them Blue Zones.

In his first book, "The Blue Zones," he chronicled the lifestyle habits these areas have in common. It was an immediate success. From there, the concept grew into an empire of several bestselling books and a mission to help communities worldwide adapt a Blue Zone lifestyle (the first Blue Zone community was in Albert Lea, Minn.) with a resource-rich website, bluezones.com, to assist.

For his latest book, Buettner limited his travels to the U.S., searching for cooks — both professional and home cooks — who adhere to the same dietary habits used in the Blue Zones. Recipes from Minnesota chefs Sean Sherman, Yia Vang, Andrew Zimmern and Alan Bergo are among the more than 100 included in "The Blue Zones American Kitchen" (National Geographic, 2023).

We caught up with Buettner via email to ask him about the book as well as his taste-tester dad, his go-to meals and to find out what's next. No surprise, he was on the road.

Q: This cookbook moved from the Blue Zones to greater America. What made you expand your horizons?
A: "The Blue Zones Kitchen" was a No. 1 New York Times bestseller so I was pretty sure readers would welcome more Blue Zones food recommendations. I started poking around for long-lived cultures in America. Working with an NYU researcher, we stumbled upon dietary surveys done [by W.O. Atwater] between 1890 and 1920s that showed African, Latin, Native and Asian Americans were essentially eating a dietary pattern that closely mimicked the Blue Zones Diet.

Q: How did you decide which chefs and cooks to include in the book?
A: I sought chefs who could bring the American Blue Zones Diet to life, specifically gifted chefs/cooks seeped in their ethnic food traditions. I hired a PBS producer, Karen Foley, to help with the search.

Q: You visit dozens of places and people from various backgrounds. How long were you able to spend with each?
A: [National Geographic photographer] David McLain, my dad, Roger Buettner, and I spent much of the pandemic crisscrossing America in Sprinter vans tracking them down. We spent about a half-day with each chef.

Q: How did you decide which recipes to include?
A: We contacted them ahead of time, described the project and the Blue Zones Diet. After some conversation, we settled on two or three recipes per chef. Upon meeting them and capturing how they made the food, I wrote down the recipe. My dad tasted many of them. My dad grew up on a farm in rural Minnesota, eating meat and potatoes. If he gave the recipe the thumbs down, it didn't make the book.

Q: What's one recipe in the book that you have in your regular cooking rotation?
A: Hoppin' John. [A recipe from South Carolina heirloom rice expert Marion "Rollen" Chalmers; see recipe.]

Q: Were there any discoveries — about the food, the people or even America?
A: The Gullah Geechee food tradition is probably the most under-celebrated in America. It fuses West African, Native American and European. Their gumbos blend okra with mirepoix, garlic, acid (vinegar), umami (fermented benne seeds) and searing hot peppers for a concoction that will make you cry tears of joy.

If you look past the TGIF and the KFCs there's a treasure trove of culinary genius in America. Sean Sherman and Yia Vang's mom (!) cooked for us locally, but also Tao Foods [in Minneapolis] has some of the most sublimely delicious Blue Zones food in America.

Q: Your "meat and potatoes" dad has been your traveling partner, taste tester and even has a recipe in the book. What have you learned about each other?
A: I learned that my dad — who was born in Staples and lived on a farm near Melrose — ate essentially a Blue Zones diet. They grew an enormous garden, canned most of the vegetables at the end of the summer, had a root cellar that preserved potatoes and such through the winter and ate meat sparingly. All their food was organic. They ate as a family. Also, my dad and I had some of the most candid conversations on these trips. One night I asked him what it was like being a father when my three brothers and I were small. To my surprise, he said he enjoyed it.

Q: You've traveled extensively for the Blue Zones. Where do you like to travel when it's just for fun?
A: In the last three months, I've been to Israel, Cuba, Tunisia, Miami, Oaxaca, Todos Santos, Los Angeles, Miami, Tortola, Nevis, and at the moment I'm cycling through North Vietnam. Next week I'll be in Thailand working on the next book. Since for work I do what I love, all my travel is fun.

Q: When you're off the clock, what's your favorite food to eat? To cook?
A: I've had some epic Jeffersonian dinner parties. I love to cook for friends. Every week I cook a huge pot of my Sardinian minestrone, which I learned from the world's longest-lived people. I start my day with it.

Q: When you're home in Minneapolis, do you have favorite restaurants or markets you frequent?
A: For dinner, I love Icehouse the best — a hidden culinary gem — Tao Foods, all of David Fhima's restaurants and Ben Graves' wine bar [The Tasting Room] in Uptown.

Q: What's next?
A: I've begun a six-country tour to work on a book that captures Blue Zones versions of the foods that Americans love the best. I'm also working on a line of Blue Zones frozen foods inspired by the world's longest-lived people with a maniacal focus on deliciousness.

The Blue Zones food guidelines

As part of his two decade-long study of longevity, Dan Buettner has surveyed the diets of those who lived the longest. His findings can be distilled into these guidelines. (For more specifics, as well as recipes and meal plans, go to bluezones.com.)

Ensure that your diet is 90% to 100% plant-based. In Blue Zones, meat is more of a celebratory food, a side or used to flavor dishes. Instead, they eat (and preserve) a variety of garden vegetables and leafy greens as well as beans, greens, sweet potatoes, whole grains, fruits, nuts, seeds and olive oil.

Retreat from meat. Research found that across the Blue Zones, people ate 2 ounces or less of meat about five times a month.

Go easy on fish. Consume fewer than 3 ounces up to three times a week. In the Blue Zones, the most common fish are the small, relatively inexpensive varieties, such as sardines, anchovies and cod.

Reduce dairy. Cow's milk isn't prominent in any Blue Zones diet, but there is a fair amount of goat and sheep milk products. And most goat's milk is consumed as yogurt, sour milk or cheese, not liquid.

Cut down on eggs. Eggs aren't a key component to living a long life, so they aren't recommended. But if you must eat them, try to eat no more than three a week.

Eat a daily dose of beans. Beans are the cornerstone of all longevity diets. They're packed with more nutrients per gram than any other food, and because they are fiber-rich and satisfying, they'll likely help push less healthy foods out of your diet.

Slash sugar. People in Blue Zones eat sugar intentionally, not by habit or accident. Buettner recommends consuming no more than 7 teaspoons of added sugar a day and skipping any product that lists sugar among its first five ingredients.

Snack on nuts. Eat two handfuls of nuts (a handful is about 2 ounces) a day, which is about what Blue Zone centenarians consume.

Sour on bread. Try to eat only sourdough or 100% whole wheat bread. Whole grains have higher levels of fiber than most commonly used bleached flours, and sourdough breads have lower gluten, and its properties can help aid digestion.

Go whole. Strive to eat foods that are recognizable, not highly processed. Blue Zone dishes typically contain a half-dozen or so ingredients, simply blended together.

Drink mostly water. Try to avoid soft drinks (including diet soda). With few exceptions, those in Blue Zones drink only coffee, tea, water and wine.

Condensed from "The Blue Zones American Kitchen," by Dan Buettner.