FORTUNE -- When Mike Lee decided he wanted to get in shape for his beach wedding, he turned to a trainer for guidance. After telling Lee that he would have to count calories to lose weight, his trainer handed him a thick, heavy book that listed only 3,000 foods and their nutritional value.
As a self-identifying geek who had been programming since he was 10 years old, Lee sought a better way to keep track of his food and exercise. The applications that were available were hard to use, so Lee decided to create his own. Working from his San Francisco apartment, he began to develop the app that would come to be known as MyFitnessPal. He shared the app with friends and family and received positive feedback. Then it began to spread by word of mouth.
Lee founded MyFitnessPal in 2005. Today, the fitness-tracking app has 50 million registered users, 3.5 million foods in its database, and compatibility with most tech wearables on the market including Jawbone and Fitbit. Lee, 43, has a bachelor's degree in economics from Princeton. He spoke with Fortune.
1. Who in technology do you admire most? Why?
One person that I admire from afar is Dennis Crowley of Foursquare. Dennis is someone who has really persevered in sticking to his vision. Foursquare has had its ups and downs, but really ever since his Dodgeball days, he's pursued his vision doggedly despite any criticism or hype. That's something I really admire. I also really like the direction the company is going in, they're looking into the idea of proactive personal computing, which I think is really intriguing.
2. Which area of technology excites you most?
Selfishly, I think the quantified self is fascinating. The amount of data that we can collect about ourselves is exploding. We're really excited about the possibilities that that enables. We will know so much about you, about where you are, and the context on your end, and we can use that data to deliver very personalized, real-time, contextual suggestions and insights. It can really be a game-changer for creating healthier habits.
3. What advice would you give to someone who wants to do what you do?
Number one is just to get started. There's no time like the present. You can't succeed if you don't try. The second piece of advice that I would give is to surround yourself with the best people possible. I always try to work with people who are better than me.
4. What's the next big project you want to tackle?
We just recently announced that we acquired a small startup called Sessions. It created this incredible coaching program that would pair you with a human coach to get you more active. Coaching is something we're really excited about. We think it will make a huge difference in helping our users succeed: having someone who can motivate you and keep you accountable.
5. If you could have done anything differently in your career, what would it have been?
I definitely would have started my own company sooner. There's an incredible amount that you can learn from working at other, bigger companies, but I've never learned as much as fast as when I started my own company.
6. What was the most important thing you learned in school?
I started programming when I was 10. As an engineer, you're always solving problems, and you learn how to break down and analyze those problems. Learning how to think like an engineer at that early age has served me well. It's something that I find myself doing constantly even for non-engineering problems. I was mostly self-taught, then would take some courses here and there. My mom was an undergrad computer science major, and so I used to audit classes with her as a kid.
7. What is one goal -- either personal or professional -- that you would like to accomplish during your lifetime?
What we're really passionate about at the company is creating a world where it's easier to be healthy than unhealthy. We live in a world today where the opposite is true.
8. What do you do to live a balanced life? What do you do for fun?
As an entrepreneur, you don't have a lot of free time. Every free moment that I get I spend with my kids. I just find it really grounding. They view the world through such simple terms that it's really fun to see things through their eyes, and it reminds you of what's really important.
9. What was the last book you read? What did you learn from it, and why did you choose it?
The last book I read was Hooked by Nir Eyal. It's a great overview of why some products are engaging and become daily habits. That's really important to us. We've seen in our data over and over that the longer you use MyFitnessPal, the more likely you are to succeed in your fitness goals. It's really important for us to get more people to use MyFitnessPal on a daily basis.
10. What is one unique or quirky habit that you have?
One thing that really annoys my wife is the fact that when I'm thinking about something I'll space out. I literally can't hear her when I'm thinking about something. I'll answer her questions and say yes or no without really thinking about what she's asking me. I like to think of it as I'm really concentrating, but I don't know if she buys that. She forgives me but just barely.
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