by Dave Asprey
To be sure, you’ll probably feel better about yourself if you complete a huge physical challenge such as a marathon. You will get a boost in confidence just by proving that you can go the distance. We often feel compelled to enter such extreme events to show ourselves that we’re in charge of our own biology, that we can to do anything. But keep in mind that 80 percent of people who take up long-distance running experience a significant injury in the first year. Heck, the ancient Greek guy who ran the first marathon died after 26.2 miles of running—not exactly a recipe for health. I’m not saying that long-distance running won’t work for you—it might—but oftentimes we enter one of these events for the wrong reasons. We approach them as a symbol of achievement rather than as part of a consistent set of decisions for creating and maintaining a healthy lifestyle.
There’s a better way to put yourself in charge.
If you want to feel better about yourself and gain the ability to control your willpower (I’m not going to call it “empowerment,” because it implies that someone else has to give you the power), fasting is the key. You can start small. First, go a morning without food. Then, when you’ve mastered that, go a day without food. I promise you that you’ll feel a distinct sensation of achievement. Just like a runner upping his or her mileage to run a marathon, you can then move up to some of the more advanced fasting techniques. You may think you can’t, but you can. Each time you successfully complete a fast, you’ll discover that it isn’t even that hard and the results are worth it. You’ll feel a sense of achievement and success. Your clothes will fit better, too.
Fasting is also a lot healthier for you than running a marathon. Or a triathlon, or whatever your big race might be. Fasting is better for you both psychologically and physically. Rather than getting a bunch of friends together for a run around your local park, ask the same people to join you in your fast. The only reason that sentence looks weird is that it is probably the first time anybody has ever suggested this idea to you. Fasting together is more important than doing endurance exercise together, but you can do both.
There’s something truly beautiful about connecting with a couple friends and saying, “Hey, let’s do this thing together.” The kind of fasting I’m talking about leaves room for social interactions. You can still meet up for “breakfast”—but skip the pancakes and instead grab a coffee (and you can treat yourself to really good coffee, since you’re saving money on food!). Instead of a boozy happy hour after work, soaking up inflammatory alcohol, you can meet up with your friends for a workout or a game of softball or Frisbee—something that actually makes your body feel good and is a better bonding activity than pounding beers and nachos.
This way, instead of feeling deprived of social engagement, you rewrite the rules of social engagement to work for you. You’re making a new kind of human connection. And when you cross the finish line and complete your fast together, the sense of achievement will be huge and totally counterintuitive. You won’t feel hungry and cranky like people on calorie-restriction diets. Instead, you’ll feel your physical and mental best. Above all, your body will be a lot less inflamed, which means that the things that always hurt will stop hurting. There’s a good chance you’ll discover pains you never knew you had; you’ll notice their absence because suddenly you’ll feel so much better.
Notice that none of this requires fixating on your health. Ultimately, your job is to be a high-performance human being so that you can enjoy all of the things that make your life meaningful. Doing that job right requires changing your connection with food so that you can tame inflammation and the other processes in your body that are currently holding you back. You have to learn new tricks that will let you master your cravings in ways that make you feel better than you did before.
An important part of that mastery will be getting used to spending time with people while they eat but you don’t. You’ll soon realize three things: First, you can still laugh and tell stories and enjoy relationships with other people even if there’s no food on your plate. Second, we don’t all need to refuel our bodies at the same time! If you don’t care that you’re not eating, chances are your friends won’t care, either. Third, some people will feel as though they’re starving when they see you fasting, and they’ll stop at nothing to try to feed you. My only advice here is to simply stick with your plan and respond to skeptics with honesty and love.
Sitting down to a meal with friends and family is a fundamentally meaningful ritual, and I would never suggest you stop doing it. Eating with other people when your body doesn’t want or won’t benefit from the food on the table isn’t a great experience, so when you do have a communal meal, enjoy it. Just don’t obligate yourself to eat in ways that you know are toxic for your body.
Break that pattern. Don’t break the fast. Take all the gifts that come with fasting—less bloated inflammation, more energy and confidence—and focus on the things that will make you feel your best.
3
Many Stages and Many Styles of Fasting
When you’re embarking on a spiritual journey, sometimes you need to let go and allow things to happen however they’re going to. You have to leave room for serendipity. Delilah put that serendipity principle to the test when she told me I’d be doing my solitary (solitary!) vision quest in the same cave as another seeker. It would be fine, the shaman assured me, as long as we both followed the rules. Rule number one: the two of us were not allowed to talk to each other in the cave. Well, yeah.
I went along with her plan, though all the while I was wondering how I was going to attain the transcendence that I had come for. The idea of experiencing true solitude while there was another person in the cave seemed as improbable to me as the idea of being able to eat while fasting. In that spirit, I almost stuffed a protein bar into my backpack (“just in case, for emergencies,” I told myself) before we headed out. It was only at the last minute that I left it behind at the shaman’s house: a wave of self-control came over me, and I removed the temptation so I could follow through on my full intent. Plus, the year was 2008, and protein bars tasted like crap back then.
Delilah drove us to the cave in her beat-up old pickup truck, looking a bit like a movie cowboy in her overalls—complete with a weathered tan and cowboy hat—and dropped us off. Before departing, she reminded my partner and me to keep space from each other, long before social distancing was a thing, and also to keep our phones powered off. The sole exception to the no-phones rule was that we were expected to power up for precisely one minute each morning in order to receive a text message from her and let her know we were okay. Thankfully, smartphones did not exist yet, so there were no other ways we could distract ourselves while we were in the cave. Except by talking. Or making hand signals.
The shaman also intoned somewhat mysteriously that she would be “checking in on us remotely,” whatever that meant. When I asked her what she was talking about, she gave a little smile and told me, “I will know how you’re doing.” Despite my attempts to pry more of an explanation out of her, she refused to say anything else. I didn’t find any hidden cameras in the cave, though.
Walking into the cave took me into a most cosmic aspect of the fasting world—the initial inspiration behind the book you are reading now.
PAY NO MIND TO THE CALORIE COPS
In the personal quest for strength and wellness, people often confuse fasting and dieting. The two certainly overlap in the general sense: Both involve going without, and in both cases you will probably lose weight and maybe consume fewer calories, too. But fundamentally, they are vastly different—as different as going into a cave alone and going into a cave with someone else. Fasting directly addresses the cravings that are holding you back. Dieting has the power to make them even worse.
The pervasive culture of dieting is a major impediment that holds people back from fasting or leads them to do it in unproductive ways. It is one reason I struggled so mightily with my weight in my twenties, losing weight only to put it right back on again.
I was already feeling bad, both physically and psychologically, and dieting didn’t help matters. Nothing makes you feel more like a failure than enduring suffering to lose 25 pounds, only to gain them back in a few weeks, plus a dozen more. The goal of diet culture is to make you feel as though a better you is just out of reach. That’s one of the many reasons why the “calories in, calories out” model, commonly abbreviated as CICO, should be relegated to the dustbin of failed science. This approach treats your body as though it’s a meat robot when in reality it’s a dynamic system that responds to calories differently based on their source, the time they’re consumed, and the unique physiological makeup of the person consuming them. Yet the myth lives on, leaving obesity, shame, and suffering in its wake.
There’s also some dubious science behind CICO, much of which can be traced back to a hugely influential physiologist named Ancel Keys. In the 1930s and ’40s he became obsessed with diet and starvation and tried to develop rigorous principles for proper eating. One result is that he invented the K-rations used to feed US Navy personnel during World War II (the K stands for “Keys”). Keys became convinced that obesity is a direct result of taking in too many calories, and he therefore advocated a low-fat, calorie-limited diet. Strangely, he did not see sugar as a problem and vigorously argued against the harmful effects of sugar when other researchers brought them to light; his arguments were finally, definitively debunked only a decade ago. Keys’s ideas were greatly amplified in the 1970s, when a US Senate committee chaired by George McGovern enshrined them into a series of federal dietary recommendations and the misguided “food pyramid” that was supposed to illustrate healthy eating choices.1
The CICO diet and its variants grew directly out of Keys’s regimented ideas about calories and obesity—including his idea that all calories are the same. Those ideas led to a clinical, unsympathetic attitude toward overweight people, which remains a central part of the ideology of the calorie counters—or, as I like to call them, the calorie police. They promote a narrative that says: If you’re fat, it’s because you eat too much. Because you’re weak. Period. The actual data, and the actual experience that I’ve lived, say otherwise: if you’re fat, it’s because your body is not effectively turning food and air into energy; instead, it is storing fat in your tissues. (In fact, inflammation is always at its root a biochemical problem involving inefficiently turning air and food into electrons.) You have a metabolic problem, not a willpower problem.
If you fall for the calorie myth, you will become disheartened when the inevitable force of hunger starts to beat you down. Every time you say no to the voice in your head that tells you to eat, it will merely come back louder. And every time you muster the conviction to deny it, you’re using up precious energy. You’re literally using up your electrons—the chemical energy that you get from activating the Krebs cycle to digest your food—in your efforts to eat less food. Not to mention that you’re spending time and focus and willpower on a losing battle when you could be allocating those resources to other important things in your life. It makes zero sense, and it’s unsustainable. It’s unsustainable because no one told you that eating just a little bit of most foods (and focusing on those foods obsessively) will cause a lot more hunger than eating nothing at all.
Eventually you’re going to give up. You will run out of willpower, and you will run out of energy to expend on fighting. This is why almost everyone who loses weight by cutting calories gains the weight back, generally sooner rather than later. A few people do manage to succeed with a CICO strategy. They are the outliers whose stories are plastered all over the news stories and the ads—until they put the weight back on later. They manage to make calorie restriction diets work by emphasizing the rules and the process—by outsourcing their willpower and by locking their food away in cabinets. But experiments show that over the long term, people on low-calorie diets, generally speaking, are incredibly unhappy. They get depressed. They learn to fetishize their constant gnawing hunger. They tend to feel cold all the time, a starvation response in which the body lowers its core temperature to conserve energy.
The results are disconcertingly similar to those of the famous Minnesota Starvation Experiment conducted toward the end of World War II. In that study, a group of thirty-six conscientious objectors followed a drastically reduced diet designed to make them lose one quarter of their body weight. It was carried out by none other than our old friend Ancel Keys. His goal was to understand the effects of wartime starvation and recovery; the results also provided a textbook example of what extreme calorie restriction does to the body. The consequences of the diet included depression, irritability, lethargy, apathy, cold intolerance, reduced sex drive, dizziness, hair loss, tinnitus, muscle soreness, clumsiness, lack of focus, and (predictably) an endless obsession with food.2
Ninety-nine percent of the people reading this book would probably say, “I’d rather die than live that life.” I’m one of them. There is some evidence that long-term caloric restriction can extend life span. But who wants to walk around feeling cold, sore, and foggy, distracted by a constant, gnawing hunger, while trying to convince yourself that these feelings are normal and somehow good for you?
Regardless of what they’re called or how they are packaged, CICO-style diets are just not good for you, because they don’t establish a healthy relationship between you and your food. Truthfully, they don’t establish any relationship at all, since they reduce food to nothing more than an arbitrary number of calories. Big Food loves CICO because it provides an excuse to package crappy, inexpensive junk ingredients as health foods as long as they are low in calories. CICO diets don’t train you to pay attention to what foods you eat, when you eat them, and how they affect you. They don’t put you in charge of your life. Fasting works much better when you learn to eat based on hunger, not calories or cravings.
When you think about it closely, the fixation on calories and calories alone makes no sense. I promise you that 100 calories of Cheetos or 100 calories of soda do not have the same effect on your body as 100 calories of fresh coconut or, frankly, 100 calories of grass-fed beef. Here’s a simple experiment to see if I’m right—I’m suggesting it here just as a thought experiment, but you could easily do it for real. Try out a CICO diet, taking in your required quantity of calories. If you’re allotted 2,000 calories a day, get all of that—just do it as nothing but soda for a couple days, and see how you feel. If you still feel the same, you must be superhuman. Captain Sugar. No normal person can pass that test. Timing also matters. Try eating all of your calories at midnight for two weeks and see how much weight you gain. Then try eating the exact same number of calories at noon for two weeks. The difference will be shocking.
You don’t need to know the biochemical explanations of why all calories are not created equal. You just need common sense. You have just disproven the calorie myth!
In the end, CICO-style diets don’t even do the single thing they are allegedly designed to do: make you thin. The calorie police will insist, “You really can lose weight if you simply pay attention to calories in, calories out.” Except that when I did that—when I genuinely went on a low-calorie, low-fat diet, complete with Entenmann’s low-fat cake and all that, and I worked out an hour and a half a day, six days a week, for eighteen months—I was still fat. My triple-pleated, 46-inch-waist pants never got too big for me.
The reason CICO diets don’t work is that your body has a set-point weight that is tied to ghrelin, the hunger hormone that you read about in the previous chapter, and to another molecule called CCK (cholecystokinin), which is your satiety hormone. When you have a high level of CCK in your bloodstream and a low ghrelin level, you feel good and are genuinely not hungry. If you are a 300-pound person, your ghrelin and CCK levels—that is, your body’s innate hunger point—are set as though you’re a 300-pound person. If you lose a bunch of weight by cutting calories, the hunger point inside you is still set as though you’re a 300-pound person. If you starve yourself to weigh 200 p
ounds, you will have the gnawing hunger of a 300 pounder. That hunger will win out against your self-control. It is inevitable.
You can hold it off for a day, certainly. You can probably keep it going for ten days. You cannot hold off the hunger and all the other starvation symptoms for six months or a year. They will come creeping back relentlessly. This is exactly the wrong way to embrace going without. If you think that people trying to quit smoking or people trying to quit drinking have a hard time, just try to quit eating permanently! That’s what your body thinks you’re doing if you go on a CICO diet. You will never find your better self this way. Small portions of most foods will make you hungrier.
I say these things as a former fat person who is no longer fat. The reason I’m not fat anymore is that I’m not hungry anymore. It’s not because I eat fewer calories! I did learn to say no to food, but in the right way—in a way that works with rather than against the biological systems inside me, by doing without food at the right time and for the right period of time. That’s what intermittent fasting is. Bulletproof Intermittent Fasting in particular is designed to get your ketones up so that you’ll feel much better than you would if you just blindly cut down on calories. C8 MCT oil contains calories, yet it enables you to fast longer and very likely lose weight, because it provides ketones that turn off hunger while simultaneously resetting your hunger set point to your current weight.
Here’s another example of the stark difference between dieting and fasting, based on an experiment I ran on myself. Ten years ago, while I was doing research for my 2014 book The Bulletproof Diet (the first big book that described ketosis with intermittent fasting), I decided to test my theory that the effects of fasting are more powerful than the effects of calorie consumption. I intentionally did everything wrong from the standpoint of the calorie-counting police. I ate a staggering 4,500 calories a day and kept doing it for a month, but for breakfast I had only Bulletproof Coffee with tons of butter to raise the number of calories in it. I cut my sleep to less than five hours a night, which triggers obesity. I stopped exercising. But I continued my program of intermittent fasting as I did all those things.
