What’s the secret to a long, healthy life? If you ask author and National Geographic explorer Dan Buettner, the answer – or answers – may be found in so-called “blue zones” – a handful of places around the world where people live longer than average, seemingly without any strict diets, expensive supplements or rigorous exercise routines.

For over 20 years, Buettner has been studying these five communities – Sardinia, Italy; Okinawa, Japan; Nicoya, Costa Rica; Icaria, Greece and Loma Linda, California. He claims that in these regions, “longevity ensues” because long-lived people are “simply a product of their environment.”

In his latest book and Netflix series, Buettner revisits these five communities and proposes a sixth – Singapore. He spoke to ABC News Live about what appear to be the commonalities between “blue zones” that have led to the highest rates of longevity.

PHIL LIPOF: Dan, thank you so much. And, you know, people will start by listening to that and going, “Oh, he has a silver bullet. He knows how to do this.” But this book and your research for 20 years shows that it is not a silver bullet, that it's actually a lot of different things, and you found these places. Tell us about them and why you wrote this book.

DAN BUETTNER: Well, on assignment for National Geographic, we set out to reverse engineer longevity. So instead of looking for it in a test tube or a petri dish, we work with demographers to find areas around the world where we know people are making it to 90 and 100 at the highest rates without the diseases that are killing Americans, and then we brought a second wave of scientists to find out the common denominators or the correlates.

And no matter where you go in Asia or Latin America, North America or Europe, essentially the same things are showing up over and over and over again at producing long-lived people.

LIPOF: And what are some of those things?

BUETTNER: Well, if you want to know what a 100-year-old ate to live to be 100, you have to know what they were eating their whole lives. So we've got dietary surveys over the past hundred years in all five blue zones, and we found that overwhelmingly, they’re eating a whole foods, plant-based diet. The five foods in every blue zone are whole grains, greens, tubers – like sweet potato, nuts and beans.

And if you're eating a cup of beans a day, you're probably not only getting all your protein and most of your fiber, but also it's associated with living an extra four years.

LIPOF: Exercise and supplements, because I know from just talking to you before we went on, so fascinating, it's not just about food. So exercise, supplements – a $151 billion a year industry. I know you say exercise has something to do with it, but supplements?

BUETTNER: Well actually, I think exercise is an unmitigated public health failure. Only 23% of Americans get the minimum, which is about 15 minutes a day.

In blue zones, they're not pumping iron or going to the gym. They simply live in places where every time they go to work and occasions they’ll walk. They have gardens out back. They don't use all the mechanical conveniences that have engineered physical activity out of our lives. They keep their metabolisms higher all day long, because they're nudged into movement. And that seems to be the big idea.

LIPOF: You spent time in these blue zones. You're spending more time in them coming up. What is it about a place like Sardinia or Okinawa that they're doing something that we here in America are not?

BUETTNER: See, that's just it. You know, in America, we tend to pursue health and longevity. We think, “OK, I want to live longer. I want to be healthier. I'm going to find this diet. I'm going to find this supplement regimen. I'm going to get on this biohack, and I'm going to get healthier.”

In blue zones, they don't do any of that. Longevity ensues. They are simply a product of their environment.

LIPOF: This was, this was interesting. I asked you if I wanted to do this personally, how long would it take for me to get started? You say about a month. But it's beyond what I want to do, right? It's what my community is doing. And when you talk about the community around you, whether it's a blue zone or anywhere that we're living, it's not just exercise. It's not just these choices you make. You say the unconscious choices. It's even about who you hang out with?

BUETTNER: Yes, if your three best friends are obese and unhealthy, there's about 150% better chance that you'll be overweight yourself.

You know, there are areas in Kentucky where the life expectancy is 20 years less than that of, say, Boulder, Colorado. That's not because people in Kentucky aren't good Americans, but they just live in an environment where it's much harder to be healthier and find healthy food and move.

LIPOF: So the you're in the right environment to make the best decisions for you. A place like Singapore. You talk about Singapore. What did they do in Singapore to buck the trends and increase average life expectancy?

BUETTNER: So I announce Singapore as a new blue zone. It's in the book, and it's a manufactured blue zone. In my lifetime they've seen life expectancy go up by almost 25 years. They now have the longest, healthiest life expectancy in the world. It’s not because sick people in Singapore have better diets.

They just live in a place where. healthy food is subsidized and junk food is taxed. Driving your car is taxed and walking is subsidized.

They’re very hard on drugs. And the most interesting thing, if your aging parent lives with you or within about 500 yards, you get a tax break, and that kind of assures that older people are cared for and doesn't rely so heavily on retirement homes, which aren't necessarily healthy.

LIPOF: All right Dan, thank you so much. The book is “The Blue Zones: Secrets for Living Longer.” And it's out [Tuesday] and the Netflix series is streaming starting [Wednesday].