by Dave Asprey
SET YOURSELF UP FOR SUCCESS
In the first century CE, the Greek Stoic philosopher Epictetus wrote, “We must undergo a hard winter training and not rush into things for which we haven’t prepared.”2 I appreciate Stoic philosophy because it addresses the challenges we choose to undertake, and the ways we prepare to face them, in ways that remain fully relevant to the modern world.
There is something to be said for a philosophy centered around enduring unavoidable hardship without complaint while constantly seeking a place of greater virtue. Whether you want to know about fasting or about how to become a highly resilient human, going back to ancient writings can help you get to the source of great truths. I read Ryan Holiday and Stephen Hanselman’s The Daily Stoic: 366 Meditations on Wisdom, Perseverance, and the Art of Living3 with my ten-year-old son in the sauna every morning while writing this book. Another quote comes to mind. “You have power over your mind—not outside events,” wrote the Roman Stoic Marcus Aurelius in Meditations, his seminal work. “Realize this, and you will find strength.”
Fasting teaches you how to summon up that power over your mind, whether it’s fasting from cigarettes, fasting from alcohol, fasting from porn (which consumes an inordinate amount of some people’s energy), or fasting from anything else you purposefully choose to go without. You’re going into battle against the inner wiring of your body when you decide to fast, so you must undergo a hard winter training. You should go in with your eyes wide open to the obstacles you will face. If you say, “Oh, this sounds great, I’m so inspired by this book that I’m going on a five-day, water-only fast,” while training for a marathon and starting a new company, I can tell you exactly what is going to happen next: You’re going to fail. You might even end up in the hospital.
Set yourself up for success. Getting your body metabolically flexible before you try the big stuff is the best strategy. Start with fasting by using the hacks I’ve outlined in this book: MCT oil, Bulletproof Coffee, sleep training, exercise training, and controlled breathing, combined in ways that make sense given your physical state and your life situation. Don’t push yourself over the edge, but don’t overlook any possible advantages, either. Don’t rush into things for which you haven’t prepared. This is good life advice for any situation but especially for fasting.
I hope you’ll indulge my sharing one more quote from Epictetus 2.10.1, as told by Ryan Holiday: “Consider who you are. Above all, a human being, carrying no greater power than your own reasoned choice, which oversees all other things, and is free.”4 Epictetus, who was born a slave, was not given his freedom until the age of eighteen. Words about freedom and reasoned choice have extra power coming from a man who once had neither freedom nor choice.
Going without, which is at the core of fasting, puts you in charge of your own freedom. It’s a big task, but if you live the rest of your life controlled by, pushed by, and ultimately allowing cravings and desires to be your puppet masters, you’ll never reach your full potential. I doubt that’s all you want from life. If you want to rise up and show yourself that you can say no for a little while, well within the safety tolerances of your body, you’ll show your body who’s boss. And the one who is the boss is you.
Many people talk about diet and fasting as if they are superficial pursuits, inward-looking obsessions in which people care only about being thin and looking healthy while not paying attention to the rest of the world. That is the exact opposite of the truth. If you want to bring something good into the world, you need the energy and focus to be able to turn it from idea into action. Fasting helps you get that energy and focus. It gives you the “Ever-So-Much-More-So” powder that lets you engage with the world as it is and make it into more of the world as it should be.
Hold on; we aren’t done with Stoic philosophy just yet. Here’s what Seneca the Younger, often considered the greatest of the Stoic philosophers, wrote nearly two thousand years ago in his Moral Letters to Lucilius, as paraphrased by Ryan Holiday. He argued that “there is no reason to live and no limit to our miseries if we let our fears predominate.”5 If that idea sounds vaguely familiar, there’s a reason: Franklin Delano Roosevelt loosely rephrased it as “We have nothing to fear but fear itself.” I got a humbling lesson about that when I freaked out over an imaginary mountain lion during my vision quest in the cave.
You now know the biology of fasting, and you know that it’s not going to kill you. In fact, if you’re doing it right, it won’t even be unpleasant. All the same, you probably don’t fully accept that truth yet because you haven’t experienced it. As long as fear remains in control, it defines your reality. Of the four F’s—fear, food, f*cking, and friends—fear is the most powerful. Even things that your rational brain knows are ridiculously, obviously not life-threatening activate the primal biological responses that are designed to prevent you from being killed. That’s why fear gets into the way of everything you strive to achieve as a human being, even something as silly as singing karaoke in a bar.
Your body will use that survival instinct to make sure you stuff your face with sugar and whatever else is nearby, because it wants to make sure you don’t go without the second F, which is food. It doesn’t care whether the food is good for you or not. All it cares about is that you don’t run out of energy. So it connects the first and second F’s with the fourth one—friends—making the act of eating a warm communal occurrence.
As for the third F, well, there’s a reason it often happens after a dinner date. The sensual pleasures and essential acts of survival and reproduction are all scrambled together in our brains. But fear is so intense that it will even overwhelm the third F. Have you ever seen someone really attractive and really wanted to ask him or her out but then didn’t have the guts to walk over and introduce yourself? That’s fear. It’s telling you you’re not that person’s equal in looks, sexuality, humor, wealth—you name it.
Are you going to endure that fear? Are you going to let it run you, as if you were still standing defenseless on the savanna in front of a hungry tiger? If so, as Seneca says, there will be no limit to your miseries. Find the thing that is the most important to you, the thing that is the most scary, the thing you honestly believe you could never go without for any length of time. Then fast from that. Go without, even if for just one day. Just long enough to make you uncomfortable. Then look in the mirror and see if you like the person who’s there.
I promise you that you’ll like that person better than you did before. That is the magic of fasting.
YOUR NEXT FAST (AND THE ONE AFTER THAT)
Throughout this book, I’ve shared my experience of the vision quest in the cave as an inspirational tale, but also as a cautionary one. When you fast from something, especially at the beginning, the volume and frequency of the noises in your head will increase. They will go from hidden whispers—soft, gentle tones you wouldn’t notice unless you were deep in meditation—to distinct, audible complaints. Then to shouts. Then to screams. Then, finally, you’ll hear raw panic fully exposed.
When the voices are at their most extreme and dramatic, that’s also when you can finally hear just how false they ring. The secret of fasting, which is also the secret of owning your own biology and your own life, is developing ways to separate truth from fiction. Your body lies to you, but it’s nothing personal. Its lies have evolved over millions of years as useful instincts to keep you alive. You wouldn’t be here today without them. Your body also tells you the truth sometimes. Once you understand that these messages are ancient adaptations to help you survive conditions you no longer face, you can begin to separate needs from wants and truths from lies.
Anyone who knows me well, or who reads my books and blogs regularly, knows that I have a distaste for certain words I call “weasel words.” These are important-sounding words that have loose, malleable definitions. People use such language when they’re not quite sure what they want to say—or when they don’t want to take responsibility for a clear opinion. We’ve all probably reli
ed on them at times to muddle through business meetings or to wriggle out of uncomfortable situations; I sure have. But they can easily lead to dishonesty, confusion, and inaction.
Need, to me, is a weasel word. It’s the most overused word in the English language, yet it is almost always untrue. The way to differentiate between a need and a want is to add the words “or I will die” to the end of the sentence. Then check to see if your “need” statement is still true. Most of the things we casually say that we need (“I need that iPhone! I need that shirt!”) aren’t needs at all. Saying that we “need” them endows all kinds of unnecessary things with power over us.
So here’s a different kind of fasting challenge: fast for just one day from words that make you weak. Language influences how we think and how we feel. If you master the word need and you stop using it in misleading and disempowering ways, every other fast you attempt will become magically easier. If you really want to spice things up, promise your spouse, your friends, your coworkers, or your kids that you’ll donate $5 to a charity each time you use the words need and can’t, another ubiquitous weasel word. At the end of the day, you will probably be wondering how exactly you’re going to foot the bill you just created for yourself.
Or you could try another very useful type of linguistic fast: tell yourself that you will use only truthful language today. It’s really challenging, harder even than you probably imagine. As part of your fast from falsehood, fast from the word can’t. This means that the next time someone asks you, “Hey, can you pick me up at the airport?” and you’re not in the mood, you want to find a way to tell them you would love to but you just . Oops. Or when someone asks you to meet for lunch and you tell them, with apologies, that you’d love to but just .
When you say you can’t do those things, you’re a liar. The honest truth—the reality—is that of course you could. You could cancel everything else and go to that lunch. You could take an hour off work and drive to the airport. So why do you say you can’t when you can and just choose not to? Maybe you’re trying to protect people’s feelings. Maybe. Or more likely, it makes you uncomfortable to stand up for yourself and say directly what you want and don’t want to do. Try it for a day and notice how different you feel. Hold on: do it for a day and notice how different you feel. (Try is another weasel word, a way to pretend you are going to do something that you probably never will.) If you’re worried about offending people, tell your friends that you’re going on a lying fast. For one day, you will tell no lies, no matter how small. They might think you’re crazy, but it will be easier if you’re truthful about it. It’s as liberating to learn to go a day without lying as it is to go a day without food.
Fasting from food is an entry point into an enormous, powerful world of honesty and control. As soon as you stop hiding in one part of your life, all kinds of other possibilities begin to open up. That’s why I’ve written this book. It’s not about helping you fit into your bathing suit or reducing your risk of atherosclerosis—though they certainly are nice bonuses. I want to invite you to open up the possibility of radical self-improvement.
Start by giving up the word can’t. Walk away from saying “need” unless you’re describing something that you genuinely, desperately do need and will perish without. These seemingly tiny challenges are incredibly difficult. But if you can remove those two words from your vocabulary for a day, you can also go a day without food. You can fast from hate. You can put more kindness and generosity into the world. You can be the true master of you.
Language may be the most powerful biohack of all. If you want to ease into your first fast with a cup of Bulletproof Coffee, that’s fine. I love it, I use it, and I will happily sell it to you. But whatever kind of fast you are planning, you will have a much greater chance of success if you work on the voices in your head first, because it will make the whole process so much easier. You will become aware of the difference between a want and a need, between a fear and a genuine danger. When you actually fast and get far into it—to the stage at which things would be going horribly wrong if your fears were correct—that’s when the voices in your head will tend to go really, really quiet. Then you will know the blissful silence that I discovered for the first time at the end of my vision quest.
In the end, fasting not only brings you physical improvements, mental clarity, emotional openness, and spiritual insight, it also brings you stillness. It brings you peace. Ultimately, that is my wish for you: May your next fast, and the fast after that, bring you peace.
Don’t be afraid to go without. It will change your life.
Acknowledgments
Every time I tell my family I want to write another book, it is with mixed feelings. My wife, Lana, and my kids, Anna and Alan, know that when there is a book in my brain ready to come out, it’s for a good cause, and they know that the longer I wait when a book is ready, the more stressful it gets. I am grateful they were supportive and understanding of all the late nights and deadlines that come on top of my normal life hosting Bulletproof Radio and running my other companies. Likewise, the people who run the companies in my portfolio know that when I go into writing mode, I am asking more of them because my brain will be somewhere else for a little while. First, I’d like to thank my family for making time and space for me to do this, on top of my other responsibilities, and I’d like to thank my team for their support while I do this.
There’s a romantic view of the lone author locked in a room somewhere writing books, but that’s not really how it works. Writing a book that is more than worth the time it takes to write and the time it takes to read is a team sport. The reason this book is the way it is now is my amazing editor, Julie Will at Harper Wave; my writing partner for this book, Corey Powell; and Celeste Fine, my agent. All of them have had so many amazing suggestions to make the book the finest possible. Thanks to Bev Hampson, who managed my packed calendar and made sure I hit my deadlines and still had time to walk the talk and take care of myself while also being an active husband, father, CEO, author, and podcaster.
Special thanks to my teams at TrueDark, 40 Years of Zen, Homebiotic and The Dave Asprey Box, Upgrade Labs, and my coaching institute, The Human Potential Institute.
I first wrote about intermittent fasting in 2010, and it was a part of my life for several years before that. Since then, so much new knowledge has come out and I am grateful to have had the opportunity to talk to many of the world’s top experts on fasting, who have helped me figure out the details, taught me along the way, and shared this knowledge with the world, including Jason Fung, Jimmy Moore, Naomi Whittel, Mark Mattson, Brad Pilon, Mark Sisson, Wim Hof, Dr. Joseph Mercola, Dr. Amy Shah, Dr. Sylvia Tara, Siim Land, Dr. Rudy Tanzi, Dr. Molly Maloof, Dr. David Sinclair, Dr. David Perlmutter, Tina Anderson, James Clement, Chalene Johnson, Naveen Jain, Michael Platt, J. J. Virgin, Satchin Panda, Matt Gallant, Mark Hyman, and Wade Lightheart.
Special thanks to a few friends who share extra business support and wisdom: Joe Polish’s Genius Network, J. J. Virgin’s Mindshare Group, Michael Fishman’s Consumer Health Summit, and Dan Sullivan’s Strategic Coach. Also, thanks to Nicole Arbour, Lewis Howes, and Jay Shetty for their continued inputs on personal development.
Assuming you are reading this, I would like to acknowledge you, for investing your time and attention in this book. I sincerely hope it was more than worth the time you put into it.
Happy Fasting!
Notes
PROLOGUE: FASTING TO FIND YOUR BEST SELF
1.Mark S. George and Jeffrey P. Lorberbaum, “Sexual Function,” in Encyclopedia of the Human Brain, ed. V. S. Ramachandran (New York: Academic Press, 2002), vol. 1, 355–65.
1: FASTING IS ONLY IN YOUR HEAD
1.Berthold Laufer, “Origin of the Word Shaman,” American Anthropologist New Series 19, no. 3 (July–September 1917): 361–37, https://www.jstor.org/stable/660223?seq=1#metadata_info_tab_contents.
2.Hun-young Park et al., “The Effects of Altitude/Hypoxic Training on Oxygen Delivery
Capacity of the Blood and Aerobic Exercise Capacity in Elite Athletes—a Meta-analysis,” Journal of Exercise Nutrition and Biochemistry 20, no. 1 (March 2016): 15–22, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4899894.
3.Cameron Sepah, “The Definitive Guide to Dopamine Fasting 2.0: The Hot Silicon Valley Trend,” The Startup, October 28, 2019, https://medium.com/swlh/dopamine-fasting-2-0-the-hot-silicon-valley-trend-7c4dc3ba2213.
4.Alison Moodie, “The Complete Intermittent Fasting Guide for Beginners,” Bulletproof, December 5, 2019, https://www.bulletproof.com/diet/intermittent-fasting/intermittent-fasting-guide.
5.Adrienne R. Barnosky et al., “Intermittent Fasting vs Daily Calorie Restriction for Type 2 Diabetes Prevention: A Review of Human Findings,” Translational Research 164, no. 4 (October 2014): 302–11, https://www.sciencedirect.com/science/article/pii/S193152441400200X.
6.Danielle Glick, Sandra Barth, and Kay F. Macleod, “Autophagy: Cellular and Molecular Mechanisms,” Journal of Pathology 221, no. 2 (May 2010): 3–12, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2990190.
7.Mehrdad Alirezaei et al., “Short-Term Fasting Induces Profound Neuronal Autophagy,” Autophagy 6, no. 6 (August 2010): 702–10, https://pubmed.ncbi.nlm.nih.gov/20534972.
8.Takayuki Teruya et al., “Diverse metabolic reactions activated during 58-hr fasting are revealed by non-targeted metabolomic analysis of human blood,” Scientific Reports 9, no. 854 (2019), https://www.nature.com/articles/s41598-018-36674-9.
9.Maria M. Mihaylova et al., “Fasting Activates Fatty Acid Oxidation to Enhance Intestinal Stem Cell Function During Homeostasis and Aging,” Cell Stem Cell 22, no. 5 (May 2018): 769–78, https://www.cell.com/cell-stem-cell/pdfExtended/S1934-5909(18)30163-2.