by Dave Asprey
The bottom line here is that women are not just men with wombs, even though a lot of the popular writing about diet and fasting might make you think they are. Women define our challenges and potentials as a species every bit as much as men do. When you plan your diet, sleep, exercise, supplements, and all of the other things that go into your fast, be mindful of the cycles and the sex-specific evolutionary legacy you carry inside you. Don’t deprive yourself of resources if you are planning to get pregnant. Never fast during pregnancy. Talk to your doctor as your body enters the changes of menopause.
But be mindful, too, of the creative and procreative sides of your evolutionary legacy. They are part of the strength you can draw upon as you experiment with ways to go without, take control, and release your better self.
10
Fast Every Way: A How-to Guide
For four days, I had struggled through hunger, loneliness, fear, and anxiety. Then, on the final morning of the vision quest, I woke to a glorious sound: peaceful silence. The bees were still doing buzzy loops around my head. The little brown bird was still thrashing about in the pile of brush I’d arranged at the entrance to the cave. No, the silence I was hearing was coming from inside of me: I couldn’t hear the voice in my head. “There’s no food. You’re going to starve,” it had lied to me. “You’re alone, so you’re going to die.” Finally it had shut up.
I had been on enough journeys like this that I knew that each experience is different and spiritual progress is an unpredictable thing. It’s far more likely to sneak up on you than to come at you directly. You can capture it as long as you’re ready and willing to let it in whenever and wherever it happens to show up. In this case, my mental state had begun to shift only after I managed to appreciate the absurdity of the things that had so tormented me over the past couple days. The bees weren’t actually harming me. The bird was not a mountain lion ready to attack. I realized that there had been a lot of silliness going on in my head. I had believed my own stories.
Beneath the silliness were the more serious cravings and the yearnings that had driven me to go on this vision quest in the first place. So much of what I was feeling was rooted in my relationship to food. Food is tied up with fear, and it’s tied up with loneliness, and it’s tied up with culture and family and what you did with your parents growing up and even how your mother fed you as a baby. These kinds of things live inside all of us, incubating and growing from the moment we’re born, and they’re not born from the world of thoughts. They tend to lurk far below the conscious level, but they sure do manage to make their presence known. To become the kind of person I had chosen to be, I had decided to deal with all of that.
I meditated for hours inside my cave. Eventually I got tired of waiting for a vision. Or had I already had one? I got up and hiked around a few of the amazing canyons that carve their way through the Sonoran Desert. I stacked up rocks into cairns, poked a cactus, and meditated some more. The vision quest was nearly over. Pretty soon Delilah would come rolling along in her battered old pickup to take me home.
I’d done it. I’d made it four days alone, without food, and I didn’t feel terrible or tired. Actually, I felt more in control than I had in a long time, maybe ever. I felt bulletproof, even though I had not yet birthed my company by that name. For the first time, I understood that the greatest gift of fasting is that it helps you divorce your story about food from the reality of your biology. My journey had given me four days of open time to examine and unpack my stupid belief systems about food. So many of the things I had blindly accepted as the way of the world were merely the result of cultural and dietary training. Social events don’t have to be built around eating and drinking (but it’s okay if they are). You don’t have to eat three meals a day. You can be in control of your hunger, rather than the other way around.
It was shocking to look in the mirror after I returned from my vision quest. My face looked different. My pants were way looser. I stepped on the scale and was baffled to see that the needle was 20 pounds lighter than before. That couldn’t be right. I knew I wasn’t dehydrated. After drinking normal amounts of water for the four days, I wasn’t thirsty at all, despite the dry desert air. I had so much water left over that I poured some out of my canteen when I left the cave. And there was no way I could have shed 20 pounds of fat in four days. Biologically—unless you’ve had liposuction—you can’t do that. I had lost, maybe, a couple pounds of fat. So where was the rest of me?
What really happened, I now know, was that my body lost a whole lot of inflammation and I had turned on ketosis. When you go into ketosis, you can easily lose 10 pounds during the first week by shedding stored glycogen along with all the water it was bound to. At the same time, I had stopped eating all food, including the foods that cause inflammation in my tissues, and started filling my body with anti-inflammatory ketones. When that inflammation went away, I dropped a lot more water weight. My whole metabolism changed in response. The vision quest was one of the first times in my life that I felt the incredible burst of energy that comes with fasting. I also felt an elevated state of mental clarity and physical lack of soreness in the joints of my back and knees, even the knee that’s had three surgeries. My body had switched into “go mode,” and I wanted to feel that way all the time.
YOUR CYCLES OF LIFE
For me, the end of the vision quest was the beginning of my new relationship with food and, by extension, my new relationship with myself. For you, the end of reading about fasting is the beginning of actually doing it. There is a beautiful circularity to fasting, as there is with life in general. We breathe in and out in cycles. We eat and drink in cycles of metabolism as well. According to one famous estimate from Oak Ridge National Laboratory, 98 percent of the atoms in your body are replaced every year.1 Almost all of your cells are replaced every seven years. Matter moves through you, energy moves through you, yet somehow you remain you—ideally, a steadily improving version of you, but you all the same.
The circularity of it all reminds me of the ouroboros, one of the oldest symbols in mythology. You’ve probably seen one—it is a snake coiled around to form a circle, eating its own tail. The ouroboros made its first known appearance on the sarcophagus of King Tutankhamen in Egypt more than three thousand years ago. To the Egyptians, the ouroboros represented an endless process of renewal. Plato later wrote about it and said the same thing. To the early Christian mystics, it evoked the merging of the physical and spiritual worlds. And to the medieval alchemists, the ouroboros was emblematic of the search for spiritual transcendence.
An essential part of the fasting process is finding the specific version of the cycle that works for you. Every person has a different state of health, different goals, different cravings to overcome. The biggest takeaway here is that there is no one-size-fits-all approach to fasting. To get the most out of fasting, you’ll need to know the wide range of techniques and hacks you can draw from. Take time to find the perfect fit, pay attention to how you feel, and don’t be afraid to experiment with different schedules. Be willing to fail at a fast. Be willing to suffer. Be willing to choose not to suffer. Think of this as part of your journey of self-discovery. It’s an expression of your uniqueness: not just your biological state but also all of the pains and pleasures and aspirations that belong to you alone.
By now you know that if you don’t eat anything for more than fourteen hours, you’re fasting. Longer fasts work better. You can fast to lose weight and fix your metabolism. You can fast to heal your gut. You can fast for personal growth and spiritual states. Heck, you can even have a few types of calories while fasting and get the same results. You are ready to start exploring and gaining control. Still, there are some common types of fasts that are either particularly easy to fit into your schedule or have been promoted enough that they have about the same meaning when you talk with others about fasting. Here is the complete list.
THE 16:8 FAST
This is the foundational style of intermittent fasting. The nam
e refers to the pattern of eating and fasting hours: you consume all of your daily calories within a shortened period (typically around eight hours) and fast the rest of the time (sixteen hours). Some people call it the “Leangains Method,” which is not accurate. (Leangains is a program2 developed by Martin Berkhan for strength athletes that uses a 16:8 fast, along with other techniques.) The simplest way to do a 16:8 fast is to reduce your pattern to two meals a day. Women may want to do a slightly shortened version; see below. A typical routine might look like this:
Skip breakfast and start your day without food. You may instinctively already do this.
Around noon, break your fast and have your first meal.
Eat dinner based on whatever eating style you like—it doesn’t have to be keto.
Stop eating by 8:00 p.m. to allow plenty of time for digestion before you go to sleep.
Repeat this schedule the next day.
If you’re a purist, you might drink nothing but water during your fast, but you can also have black coffee or tea.
BULLETPROOF INTERMITTENT FASTING
This one is my go-to fast, and it will probably be yours as well for the reasons described in previous chapters. It uses a fast of at least 16:8 (or longer), but with one crucial biohack to make your fast easier and more effective: drink a cup of Bulletproof Coffee in the morning. The medium-chain triglycerides (MCT) and high-quality fats from grass-fed butter keep you feeling full until lunch, yet they also allow your body to continue autophagy and fat-burning so you get all the benefits of intermittent fasting. You can add a tiny dollop of butter and a dash of C8 MCT oil, or you can go bigger if you have a big day. Yes, you’re really fasting!
I came up with Bulletproof Intermittent Fasting ten years ago to address the one huge downside of regular intermittent fasting: it can leave you feeling hungry, tired, and distracted, especially when you’re first getting started. It’s hard to focus on crushing your to-do list when your brain is constantly thinking about lunch. To get the benefits of intermittent fasting, you need to stick with it and power through the initial feelings of fatigue. All too often, those hunger pangs cause people to give up, because we have jobs to do, kids to raise, errands to run, or other responsibilities to attend to while we’re fasting.
Bulletproof Intermittent Fasting solves a lot of those problems and helps ease newbies into the world of fasting. When you start your morning with a cup of Bulletproof Coffee, the fats push your body into a mild state of ketosis, which curbs your cravings and fuels you with energy-rich ketones all morning long. Best of all, it does these things without switching on protein or sugar digestion and all of the chemical work that goes with it. By avoiding carbs and proteins, you continue to reap the benefits of a fasted state—without feeling like a hungry zombie.
If you want to make sure that you’ve optimized your Bulletproof fast, you can easily test your ketone levels at home. Ketone testing strips are sold online, as well as in most pharmacies. They’re simple to use: they change color according to the number of ketones in your urine, which tells you if you’re slightly in ketosis or deep in ketosis. The magic ketone number you want to hit is 0.48 mmol/L, but the affordable “pee strips” won’t give exact numbers. For that, you will need to buy a far more accurate Precision Xtra ketone meter. You prick your finger as you would for a blood sugar test, get a pinhead-sized drop of blood, and stick a test strip into the meter. It provides a very precise digital measurement of your blood ketone levels. It will make sense as soon as you get your hands on a kit.
First test your ketone levels to get a baseline. Then make your Bulletproof Coffee, starting with one teaspoon of Brain Octane MCT oil in your coffee (Brain Octane MCT oil raises ketones more than normal MCT oil does), drink it, then test your ketone levels forty-five minutes later to see the spike. Gradually increase the Brain Octane MCT oil you take over the next few weeks until your ketone level is above 0.48 mmol/L. Then see how you feel: Are you able to power through your morning without thinking about lunch? If not, you can keep adjusting.
A typical day of Bulletproof Intermittent Fasting might go like this:
Drink a cup of Bulletproof Coffee in the morning instead of eating breakfast. No sugar, no cream, no fake creamer, no artificial sweetener.
Either skip lunch for a longer intermittent fast, or eat a late lunch according to your food template (bonus points and faster progress come from using the Bulletproof Fasting Roadmap at daveasprey.com/fasting).
Finish eating by 7:00 to 8:00 p.m.
Repeat this schedule every day or just a few times per week. Remember, your body hates strict routine, so feel free to mix it up.
THE 5:2 FAST
In this case, the numbers refer to days rather than hours. On a 5:2 fast, you eat normally five days a week. On the other two days, you drastically reduce your intake to between 500 and 600 calories. This sort of fast is focused primarily on weight loss, which is why it is sometimes called the “Fast Diet.”
There is good evidence that people lose weight on this diet. However, given that you can eat whatever you want on the days when you’re “fasting,” you’re unlikely to get the benefits of autophagy. The only thing you’re really going without is lots of calories on two days of the week.
There are no standard guidelines for what to eat on your fasting/dieting days. Obviously, you want to go for the highest-quality foods that fit into your diet (not 600 calories of potato chips!), but some form of fasting is always better than no fasting at all. You can also experiment with when you want to take your calories on fasting days, as long as you don’t do it close to bedtime. You might want to take three very small meals, though you will probably have better results by bundling your calories into just lunch and dinner.
The 5:2 fast is broadly similar to alternate-day fasting, which is exactly what it sounds like. Because alternate-day fasting is straightforward to test in the lab, it’s used in many studies of the effects of intermittent fasting. Some of the well-documented health benefits3 include weight loss, reduced insulin resistance, reduced allergies,4 decreased inflammation, decreased oxidative stress,5 better cardiovascular health,6 and overall improved metabolic fitness. Note that these benefits are not unique to alternate-day fasting. You will achieve them in most if not all forms of intermittent fasting.
ONE MEAL A DAY (OMAD)
In this fasting plan, you eat one meal a day. Calling it OMAD sounds more badass, though, so that’s what most people do. Strangely, when you tell someone you are eating only one meal a day, they don’t react nearly as strongly as if you say you’re fasting. It’s because they hear that you are eating, instead of going without. In OMAD, you consume all of your daily calories in a single meal and fast the rest of the day.
In other words, OMAD is a 23:1 fast, which gives your body twenty-three hours each day to reap the benefits of a fasting lifestyle. If you’re looking to burn fat, improve mental resilience, and minimize the amount of time you spend on your food schedule (you know, if meal prep and eating feel bothersome to you), you should investigate this one. Of course, if you did 22:2, or 20:4, you would also get the same basic benefits. So it’s a bit silly to single out the twenty-four-hour OMAD fast with a special name, but if sounding badass helps get you into fasting mode—embrace it.
For most people, between 4:00 and 7:00 p.m. is an ideal time to break the fast with your daily meal. That window gives you fuel when you need it most; it also provides a time to eat socially with friends or family and leaves enough time to digest your food before heading to bed. Intermittent fasting schedules above 16:8, such as OMAD, activate stress response pathways that boost mitochondrial performance, autophagy, and the repair of the DNA in your cells, as well as reducing the risk of chronic disease.7 The extra few hours beyond 16:8 do provide additional benefits.
On the other hand, OMAD can be a pretty extreme intermittent fasting schedule if you do it every day, especially if you are new to fasting. Avoiding food for twenty-three hours a day takes a lot of effort, and if it str
esses you out, you will lose some of the powerful benefits of fasting. It’s also especially challenging for women for all of the hormonal reasons discussed in chapter 9. The goal here isn’t to feel as though you’re punishing your body or suffering through a challenge. Fasting does not need to include suffering—unless you want it to. A successful transition to intermittent fasting requires training your body to handle a new routine and then working to make it sustainable. In general, I recommend doing OMAD no more than three times a week.
I often find that when I do a 16:8 Bulletproof Intermittent Fast, when lunchtime rolls around, I’m not hungry. So I skip it. By dinnertime, I’ve magically completed a 23:1 OMAD fast. It’s much harder to wake up and tell yourself, “Today I’m doing an OMAD fast,” than it is to tell yourself at lunch, “Hey, if I just wait six more hours for dinner, I am in OMAD land!”
Here are a few tips to get the most out of an OMAD fasting plan:
Introduce intermittent fasting every other day.
Start by fasting in shorter durations. Get comfortable fasting for sixteen to twenty hours at a time, and slowly build up to fasting for twenty-three hours a day.
Try one 23:1 day, then add more, at most three, OMAD days into your weekly routine. As with any style of fasting, it’s important to see how your body responds and find what works for you.
Eat according to your food template; OMAD works with all of them, but most people on OMAD choose to limit the amount of carbs in their diets or to eat according to the Bulletproof Fasting Roadmap at daveasprey.com/fasting. When you eat a lot of carbohydrates, your body stockpiles glucose as glycogen and it takes a lot longer for your body to shift into ketosis. You can also modify OMAD to include a cup of Bulletproof Coffee in the morning, which is a great hack to have more energy during the day, or with prebiotic fiber, which is a hack to keep you from being hungry while feeding good gut bacteria.
