It’s amazing how much nicer people are when they have energy. This according to Dave Asprey, who, more than 20 years ago, began a personal journey of health and wellness that he’s transformed into the wildly successful Bulletproof Coffee and two best-selling books: The Bulletproof Diet (Rodale, 2014) and his latest, Head Strong (HarperCollins, 2017).

What triggered you to go on your two-decade odyssey to hack your own biology?

I was in my 20s and profoundly successful in Silicon Valley…and I weighed 300 pounds. My brain was all over the place. I got medical tests, I worked out every day, I ate low fat, but I was still overweight. Then one day I realized: This is not me; I’m doing the wrong things. So I developed a practice of “biohacking,” realizing that I could take charge of how I felt.

Please explain “biohacking.”

It’s the art and science of changing the environment around you and outside of you so that you have full control of your biology. I had made a career of managing complex systems, so I thought that maybe I could do something similar for myself. I started an anti-aging group. I started running. I researched about health online until I fell asleep at my desk. I got smarter. I got thinner.

As part of your biohacking practice, you traveled the world. Can you share a memorable experience?

I went to Tibet to learn meditation at the base of Mount Kailash, which is at 18,000 feet. I wasn’t feeling well, and a woman gave me a cup of tea with yak butter. I felt better than I had in months; it was so unlikely and profound. This planted the seed for Bulletproof Coffee and the Bulletproof Diet.

Tell us about Bulletproof Coffee and the Bulletproof Diet.

When I came back from Tibet, I couldn’t get yak butter, so I bought regular butter and blended it with coffee. It was gross. After extensive testing, I discovered that butter from grass-fed cows worked because of its special fatty acids. So I invested in a line of ultraclean, Guatemalan-grown coffee that you can add grass-fed butter and another product, Bulletproof Brain Octane, to energize your mind and body for hours.

The Bulletproof Diet book followed. After spending so much time and money on myself to get my biology where it is today, I wanted to share this experience with people struggling with health issues who don’t have the time and resources I have. I wrote the book because I want people to learn how to feel the way I feel. One of the things I discovered is that when you eat foods that are not compatible with your biology, you have less energy and focus. So I developed a road map of foods that, as you follow it more closely, the more bulletproof you’ll become.

Tell us about your new book, Head Strong.

I wanted to write more about willpower and how you can hack it. If you don’t have willpower, it’s not that you’re weak or don’t try enough. It’s a physical thing in your body, and you can change it. You have way more control than you ever thought possible of your body and mind.

How are you feeling today?

I am 44. I’m 100 pounds lighter. I’m a dad, a husband, a CEO and a book author. I have a brain that works. I have energy. My emotional regulation is incredible. I’m full of energy because of biohacking. And I’m planning to live until I’m 180.

Download the Bulletproof Diet Roadmap at blog.bulletproof.com/the-complete-illustrated-one-page-bulletproof-diet.