In this week’s Fit For Business, Well+Good’s co-founder and CEO Alexia Brue sits down with Siggi Hilmarsson, the CEO, founder, and namesake of Siggi’s, the Icelandic yogurt brand that introduced healthy Americans to skyr.

Yogurt is undeniably having a moment (beyond just breakfast)—and in a crowded field, Siggi’s has been the fastest-growing yogurt brand in the United States for the last three years, according to Nielsen.

It’s no surprise, given the intense consumer focus on low-sugar foods that are packed with protein. Today you can find cups, bottles, and tubes of the understated yogurt brand with big ambitions in 25,000 stores across the country—including 7,000 Starbucks. Yet it started in 2004 as the the passion project of a Columbia MBA student named Siggi Hilmarsson who missed the thick, unsweetened yogurt from his native Iceland.

“Her colleague said, ‘These are really good. If you ever make it, we’ll stock it.'”

“After making yogurt as a hobby for several months, one of my business school professors—who had been a successful entrepreneur himself—said, ‘If you’re quitting your day job and doing this for real, I’ll be your first investor,'” recalls the Icelander. “Then around the same time, I gave samples to a friend who worked at Murray’s Cheese [a legendary New York City cheese shop] and her colleague said, ‘These are really good. If you ever make it, we’ll stock it.'”

Make it he did, and today the basketball-playing founder and CEO helms a team of 42 in his adopted city of New York (“I love the fact that you can walk outside in one neighborhood, and then five minutes later you’re in a totally different area,” Hilmarsson says of his home base).

Here, Siggi’s namesake shares the lessons he’s learned as an entrepreneur—from embracing the “white space” to not forcing company culture.

First things first: What’s the difference between yogurt, Greek yogurt, and skyr, the Icelandic type of yogurt you make?

Skyr and Greek yogurt are sort of close cousins—they’re both what you would call strained yogurts. If you think about yogurts as falling broadly into two buckets, one is regular yogurt, where you basically just take regular milk, you culture it up, and it becomes a little bit more gelatinous. But it’s runny—you can almost drink it. That’s regular yogurt. And within that regular yogurt span, there are a bunch of different varieties, like Bulgarian, French, Swiss. They use different cultures, some are a little bit tarter than others, some have a little bit more body, [but] they’re kind of similar.

Then there’s your other class of yogurt, where you start off by making regular yogurt—and then you strain a lot of water out of the yogurt and you make it denser. And that’s a strained yogurt. There are a bunch of strained yogurts around the world—skyr yogurt is one of them, Greek yogurt is one of them. And in America, Greek yogurt is so popular, it’s kind of synonymous with strained yogurt. Greek yogurt uses about three times the milk [of regular yogurt] to make one cup; skyr is usually around four, so it’s a little bit denser. That’s why it’s more expensive, because you’re using four times the milk. And that’s why the protein content is higher.

“If you do something and it fails, and you never liked it in the first place, it’s really awkward and embarrassing, right?”

What led you to take the leap and launch Siggi’s?

I had the courage to launch because I liked the product so much that I knew I wouldn’t feel super awkward if I failed. If you do something and it fails, and you never liked it in the first place, it’s really awkward and embarrassing, right? My passion for the product kept me going during some of the darker moments, when things were not going really great and I was losing sleep and worrying. If I couldn’t sleep, I would always eat that yogurt cup, and I would be like, “Ah, okay. At least the product is really good. At least I really like the product and I’m losing sleep for something I really care about.”

What were some of those early challenges?

In those early early days, we just couldn’t make enough yogurt because we were doing everything by hand. We didn’t have a way, for example, of taking out the water from the yogurt. We were actually pulling it like the old-school way in cheese cloth. But then we got that capacity, and we started scaling up. It was fortuitous because at [that] time Whole Foods approached us and said, “Hey, wow. We really like this.”

We had our worst moment probably in 2008, when we were trying to scale up to distribute outside of New York to lots of East Coast retailers…and our plant went down! We had to rebuild it basically from scratch over the course of a three- or four-month period. I didn’t sleep a lot. You doubt yourself every day, and then when it’s up and running, you’re almost too beat to celebrate and you just are worried about the next thing.

“Often what gets you from A to B are not the same actions that get you from B to C.”

Can you share a key decision that you made that was a real turning point for Siggi’s.

We later had to move our plant again when we were further scaling. That was a difficult call because we’d been with them for a while, but we really had to go to a more professional facility. Often what gets you from A to B are not the same actions that get you from B to C. Like, if you take what you did to get from A to B and do it times two, it’s not the same.

What’s to come from your growing yogurt empire?

We still have so much of what we would call “white space”—that’s the most interesting thing about the business right now. When we started, the people who were eating Siggi’s were all people who were really into health and balance, and they realized the benefit of eating less sugar. So we did really well selling to health-food and natural-food stores, but we weren’t growing very fast in mainstream grocery [stores]. Over the past three or four years, Americans have become so much more aware of sugar than they used to be. We’re still underplayed in a lot of stores and a lot of retailers, so we have a lot more room to grow.

Where did your entrepreneurial drive come from?

People in Iceland are pretty independent-minded; I don’t want to use the word “stubborn”, but they kind of are. I had that notion very, very early that I would do something that was not dependent on other people. I didn’t necessarily know what it was—it could have been so many things—[but] ideally, I wanted to create something.

What keeps you inspired and nourished as a person?

I play a lot of basketball and have a regular game—that has kind of been my yoga. Also, I read a fair bit of literature, as well as business books. A recent favorite was Crossing the Chasm by Geoffrey Moore.

“At any given time, I try to have two or three key things that I’m focusing on, as opposed to checking in on every single project.”

How do you walk the walk as a healthy food company?

People can obviously eat as much yogurt as they want to. [Laughs] As a company—and as a boss—we’re sort of laid back about that kind of stuff. We try to get everybody together once a week for a family lunch, and we rotate who gets to order. We play ping pong sometimes Friday afternoons, and there’s usually a weekly happy hour. I think it’s best where you lead a bit by example, but at the end of the day you don’t want it to feel stifling. It’s not a cult.

What’s your favorite efficiency hack?

It’s kind of obvious, but what I’ve learned is to have a great team of senior people who I just trust. At any given time, I try to have two or three key things that I’m focusing on, as opposed to checking in on every single project. I trust my senior leadership team a lot.

What advice do you give would-be entrepreneurs?

Plan for success. Obviously I thought and hoped Siggi’s would be a big success, but I didn’t act on it being big. When we started growing, we had big issues supplying, and so basically what happened is I didn’t really plan for being successful; I planned for continuing to be a small business that was growing by a couple of stores at a time. So plan for success.

Other exec-approved ways you can maximize efficiency is to set certain email-only times in your schedule or to rethink the way you approach meetings.