Inside Silicon Valley’s Dangerous Game of Occasionally Not Eating

science, culture, and a journey through the world of fasting

Day One - Exiting the Pyramid

On December 17, I stopped eating for seven days. I consumed nothing but water, coffee, and an occasional pinch of salt. I did it to achieve cellular regeneration, spiritual contemplation, and a temporary break in my furious, constant consumption of every calorie within ten feet.

I was following in the footsteps of a man who tried to starve himself to death. In 1887, Dr. Henry S. Tanner stopped eating, having apparently decided that he deserved an agonizing demise after failures in marriage and business. As the first few famished days passed, he wondered when the sweet release of death would cease its tardiness. But, by the tenth day, he didn’t feel hungry anymore—in fact, felt vigorous and healthy. He saw no reason to stop fasting, and, in the end, fasted for a month, before repeating the feat repeatedly in the presence of puzzled doctors.

However, though Dr. Tanner did much to popularize fasting in the modern era, he wasn’t my immediate inspiration. I’d been influenced to try water fasting by friends in the tech sector, where fasting has become something of a trend. Not everyone is happy about this. The Harper’s Bazaar article “Inside Silicon Valley’s Dangerous New Obsession with Fasting,” for example, claims that fasting is merely disordered eating rebranded and that its tech sector purveyors are being unjustly lauded for habits that are condemned in teen girls. There’s also this one, and this one, and many other works of literature penned by the nutrition and psychology experts of progressive Twitter.

They’re all mostly wrong. They’re also probably somewhat culturally motivated; it’s hard to imagine any of these publications putting out something called The Dark Side of Ramadan: Inside the Muslim World’s Dangerous Obsession with Fasting.

But I don’t blame them for being wrong. Their opinions are to be expected. They’ve been educated by a culture that teaches you the gospel of three meals a day, every day—that constant eating is a necessity for happiness. From birth, they’ve been pumped full of propaganda prepared by agribusiness and government, including conceptual ideas like the Food Pyramid, that compellingly geometric menu that has dug many an early grave. If I told them, or, really, most anyone off the street that I wasn’t going to eat for seven days, they’d probably wonder if I were committing suicide.

But fasting for surprisingly long periods of time doesn't actually seem dangerous, for most. In a sense, this finding is obvious; if human beings weren’t able to use our fat stores to survive, we wouldn’t have made it out of the ancestral environment, where occasional scarcity was simply a given.

However, fasting is hazardous, in a way. It punches this weird food-shaped hole in consensus reality. Doing it can change the way you think about, at the very least, food, disease, and the progress of science—which is to say, a big chunk of human life.

Oh, and, at times, it does totally suck. The first day is tricky. Your body is trained by your normal habits, developing hunger pangs in response to the release of a hormone called ghrelin. When you just skip all of that day’s meals, the ghrelin assault is uncomfortable. But then you sit through it, and your hunger pangs just… go away, leaving you, mysteriously, alive.

Day Two - Big Nothing

Sometimes, I wish there were a Big Nothing lobby—some sort of agency devoted to studying what would happen if we did less. For example, let’s say the government became fixated on some problem with social welfare. Is there anyone to study what would happen if we did nothing? Would it just get better on its own? Similarly, what would happen if, in response to population-level health issues, instead of taking supplements or treatments, we just ate nothing for an interval?

Unfortunately, profit motives rule out this potential world. There is no Nothing Lobby. Which is a shame, because if Pfizer or Merck stumbled upon a drug that could do half of what fasting appears to, their entire R&D apartments would be frothing at the mouth and gripping their calipers tightly. 

Though it’s touted as a weight loss intervention, fasting’s health effects go way beyond that. When you read the fasting literature, you have all these moments of, like, what, really? For example, if you come down with cancer, you might want to fast, because fasting appears to protect the body during chemotherapy, allowing higher doses of radiation to be administered with fewer side effects. On the other hand, maybe you should’ve fasted earlier: studies in mice suggest that fasting might be effective in slowing or preventing tumor growth. If you’re just not interested in getting sick at all, you should know that fasting appears to promote the generation of new white blood cells, thus potentially reinvigorating the immune system. It could also keep you sharp, and by that I mean keep you sharp when you’re 80 years old. Fasting appears to promote neuronal health, potentially making it a defense against neurodegenerative diseases.

But, if weight loss is what you’re looking for, supervised fasting appears to be strikingly effective. For example, in 1965, a 456lb man named Angus Barbieri went without eating for a year with no apparent negative consequences, went down to around 180, and kept the weight off for his whole life. And, while this result is uncommon in degree, a brief peak at reveals that it’s not unusual in kind.

We maybe understand why this happens. It seems to be down to autophagy—literally, self-ingestion. Your body constantly recycles old material, but, when you’re fasting, that process is dramatically accelerated. Old cells are broken down. Excess fat is turned into ketone bodies so the brain can continue operating. (Many who lose weight during fasting are surprised to find that they don’t have loose skin because their bodies literally ate it.) After all of the old stuff is recycled, the hypothesis goes, your body functions better.

But, overall, we’re still ignorant of the mechanisms of water fasting, despite the fact that it’s been advocated for thousands of years—Pythagoras required it of his students, finding that it promoted lucidity and focus. We don’t know what the ideal fasting protocol is. We don’t exactly understand its effects on longevity. It’s possible that repeat fasts in a short period of time could be damaging, specifically to the kidneys—where exactly are the healthy limits? We don’t know.

Several luminaries of the fasting scene, which is a thing that exists, have figured out how to make money off Nothing. One prominent advocate of no food, Dr. Jason Fung, sells highly readable books on fasting and helps run a clinic that coaches people through the fasting lifestyle. Another, Dr. Valter Longo, also sells books, as well as ready-made meals which are low-calorie enough to help fasters maintain a fasting state, but nutritive enough to make the process more tolerable.

This is all great, but, for the time being, the Nothing Lobby will be eclipsed by the mountains of cash involved in soybean oil, corn syrup, dietary supplements, and bariatric surgeries. And so, for the foreseeable future, fasting may remain poorly-explained and under-promoted, a personal rebellion against the entrenched interests undermining our health.

Perhaps this should make us furious. I know a fair number of fat people who want to lose weight. They’re given diets that don’t work, supplements that don’t work, and then shamed, which also doesn’t work. But, as it turns out, they might not need any of that. With medical supervision, they could probably solve the problem by not eating for a month or two. It could be a really shitty month or two—but better than struggling for decades, if losing weight is what you want to do. But if they read Harper’s Bazaar, or other maintainers of the dietary Overton Window, they might be dissuaded from even investigating this possibility.

On day two, fasting is doing weird things to me. Usually, I’m hot all over, but, without calories, my extremities go through thermal alternation—my nose is cold, then hot again. My breath smells great, then awful. At random moments, I’m seized by waves of incredible energy, thoughts of conquest, and the lust for food. At other moments, I lust for nothing and dwell in profound neutrality. I’m more diurnal; whereas I normally tend towards nocturnal activity, I wake with the sun, and my energy plunges the moment it’s dark.

Day Three - First Principles

Perhaps one reason that fasting has become popular in Silicon Valley is that it’s an applied crash course in First Principles Thinking. This term has only become a tired cliche in tech circles because it’s a principle that’s served so effectively in the past. The best (and worst) technological innovations have come from asking questions so basic only a curious child or a frenzied entrepreneur would think to ask them, and the process continues today. We don’t live on Mars. Why? We have to drive our cars. Why? We should eat a shit-ton of food every day, without interruption. Why?

The reason is not immediately apparent. On the third day of my fast, I wake up feeling fine, if still not totally normal. There is this basic knowledge that my bowels are empty. My interior feels strikingly vacant. But, generally, my physical condition is less notable than it was the day before.

What’s more notable is how surreal it all is. Our days are broken up by meals and punctuated by snacks. Once you take that away, what’s left? 

Great expanses of time. The day just goes on and on and on. In that ocean of minutes, I’m unusually productive. Uninterrupted by the 100,000 snack breaks I usually take in a day, I double my usual daily writing output. Moreover, I’m weirdly focused. The energy that would usually go into digesting fistfuls of random stuff from the fridge is being directed into my laptop. 

There’s a change in mood, too. Most emotion drops away, positive and negative. I’m not interested in listening to fun music, nor can I bestir myself to become angry at the Internet. I’m neutral, lucid, highly aware. I’m a hungry ghost, haunting my computer. In some ways, going without food for 24 hours has made me better, although I’m probably also less fun to hang out with. 

I discuss this with Geoffrey Woo, Founder & Executive Chairman of HVMN, a fasting-happy company that sells ketosis-promoting products. The people at HVMN began fasting together when they noticed that one of their first employees didn’t die despite fasting every week from Sunday to Tuesday, and was, in fact, happy and productive. Though their work has become asynchronous thanks to the pandemic, the company remains enthusiastic about it, privately co-ordinating fasting and feasting in order to add a social dimension to an otherwise solitary activity. 

“It’s a very calm, clear, zen mental state. It’s almost a spiritual experience. I try not to get too into evolutionary biology because it’s easy to retroactively fit observations into that framework. But, when your body is in this starvation survival mode, it’s plausible that it’s getting sharper because it needs to be on top of its game. You’re on a mission.”

As for First Principles Thinking, Geoffrey’s answer to the question of why we eat all the time isn’t just agribusiness—it’s also down to a historical hangover. “The modern food system, as defined as what’s happening today, was optimized to solve a 19th-century problem. The biggest issue was famine, lack of access to food. Innovation responded, and said, let’s get a shitload of calories that are cheap and shelf-stable.” The results were positive in the short term, but famine is no longer the problem, and the incentives involved in selling shitloads of calories remain.

And what about the charge that Silicon Valley is promoting eating disorders? “When people make that argument, I say, you tell me what’s disordered. 88% of [Americans] are metabolically dysfunctional, 3/4s of us are overweight or obese. Who the fuck is eating disordered?” He acknowledges that fasting could feed into eating disorders, but notes that, well, there are different humans with different issues—nobody needs to make categorical declarations that fasting is good for everyone. “We can address those with mental disorders like eating disorders as separate subpopulations.”

Geoffrey tells me that, at three days into a fast, hunger usually drops off dramatically. And it’s true that my normal hunger pangs are mysteriously absent. But my food-related desires still exist—they’re just sort of artistic, instead of visceral. For the first time in recent memory, I recall the taste of fried spam sandwiches on soft rolls with mayonnaise, and try to sketch it in perfect detail on my mental palate. I start ruminating on all the good food that exists in tube form. Tamarind. I remember that tamarind exists. This is shocking, near-unbearable knowledge.

Day Four - Self-Carelessness

To state the obvious, as a civilization, we’ve done everything we can to remove any form of resistance or discomfort in our lives, and the results have often been disastrous.Somehow, it turns out that nearly every time we remove one of the thousand natural shocks of existence, we find out that we needed it, and we have to replace it somehow. Exercise, Vitamin D supplementation, Slack channels—these are all contrivances designed to replicate things we’ve lost.

What if hunger is in a similar category?

As a culture, we fret endlessly, for good reason, about how to deal with the rising tides of obesity and diabetes. And, largely, the fretting takes the form of wondering what we should eat—which nutrient profile is optimal, what supplementation we might need. But this is all kind of stupid, given the variation we see in traditional diets. If you think that low-carb is the way to go, it’s hard to explain the vigor of Irish peasants, or the remarkable health of Okinawans, who mostly ate sweet potatoes and whole grains before we ruined their diet. Fan of plant-based life? The Inuits do pretty well with no dietary fiber intake whatsoever. Think sugar is the issue? Tell that to the Hadza people of Tanzania, for whom honey is a cornerstone of nutrition. Even a quick survey of humanity reveals that we’re truly omnivorous. Every traditional diet is better than the Western diet, but they’re all totally different.

So, why is the Western diet so bad? As is documented by Stephen Guyenet’s excellent book The Hungry Brain, it’s probable that it’s because our diet gives us brain damage. Our food is incredibly delicious and varied, so our bodies consider it extraordinarily valuable, so we over-consume. Once we chronically over-consume, our brains, which manage our appetites in order to maintain a set weight point, nudge that set point higher and higher. We inch towards obesity, and our bodies defend every inch. We remain prisoners to our hunger unless we can manage to eat a more traditional diet—which is to say, a highly restricted diet, less appetizing due to its lack of variety. Empirically, few of us can do this.

But there’s another option. We could regard hunger differently. We tend to think of hunger as a pressing need, which will cause total emotional and cognitive collapse if left unchecked. But what if we thought of it as resistance, as we do in exercise? When you’re exercising, you don’t freak out about your muscles being taxed. You accept it as part of a healthy process. Hunger is a signal, just like sadness, jealousy, pain, and cold. It’s not a command. We don’t always have to listen immediately, and, occasionally, we can stop listening for days at a time, and will probably benefit for doing so. And then we can eat whatever the fuck we want.

Some who agree with me adopt the One Meal a Day plan, which is exactly what it seems like—eat a whole bunch, once a day, with only passing attention to what the meal is. Reports seem to indicate that it makes you pretty surly at first, but then you get used to it and tend to lose weight. As for the Zero Meals a Day plan, four days in, I’m gaining a newfound respect for just how incredible my human machinery is. I’ve transitioned into deep ketosis, which means that my brain is being powered pretty much exclusively by fat stores. I’d imagined that this would be an incredibly grim time, a time of lurking, wilting, and anger. Instead, I watch A Christmas Carol in my neighbors’ backyard. They’ve provided cookies, pizza, and Glenlivet for the occasion—three substances I’ve had loving relationships with. I turn down their offers, and am chatty and cheerful, with no visible impairment. I’m tougher than I’ve been taught I am. I’ve been lied to, my whole life, by the Experts, about the schedule of my body’s needs. Given this incredible fact, I have to wonder how else I’ve been lied to.

Day Five - An Alternative to the Divine Burger

When Geoffrey Woo told me that fasting was a spiritual state of mind, I was pretty skeptical. For me, the most readily available spiritual experience is a Double Double Animal Style at In-N-Out. Certain meals can make me cry. But then I hit day five, and there was a shift.

Many dimensions of spiritual experience, whether meditation, prayer, or pilgrimage, involve stripping things away. The goal is to quiet the buzzing elements of consciousness that can stop us from appreciating the essential wonder of existence. It’s just fucking great to be alive, right? Nothing we hear on Clubhouse should make us feel that it isn’t. God, or whatever you put in God’s place, is all around us. But that’s hard to remember.

On the other hand, at a certain point in the fast, the blooming confusion just disappears. It’s simply gone. That thing we occasionally call Monkey Mind has been turned off in favor of one of the most basic monkey functions—survival in the face of scarcity. And what’s left is an utterly basic state of mind, less conceptual, more sensuous. You are There. It’s not good, it’s not bad. It’s just Suchness. Mere Being.

Driving on the highway, amidst a sea of red brake lights, I felt my presence among the mass of humanity, like one blood cell in an artery, different from but also the same as everyone around me. Walking on the beach with my wife, I felt no essential boundary between my skin and the air, between my feet and the sand, between my fingertips and the rock mussels I bent down to touch. I was a part of everything. And, when I attempted formal meditation, I found it easier to slip into a state of profound concentration, although there wasn’t any bliss to speak of. Maybe the Jains, who fast regularly as a spiritual practice, are onto something. (Some, at the end of their lives, choose to fast to death, rather than undergoing traditional palliative care.)

And yet. This week, my downstairs neighbors have chosen to intensify their carnivorism. Daily, odors of steak and stew fill my apartment. The odors are so vivid that it feels like a 3-D painting of blood and triumph has been hung on my head. My sense of smell has sharpened, and I involuntarily appreciate every nuance of the tiny particles of flesh on the breeze. Sleep is difficult. 

Day Six - On the Other Hand

So, to this point, I’ve defended fasting as a health intervention, a spiritual practice, an education in one’s bodily faculties, and a personal rebellion against the commercial incentives that poison us. And I think that’s all true. I think Alex Kuczynski is being incredibly facile when she lumps fasting and eating disorders together.

But, okay, let’s admit it. Fasting is kind of crazy. At the very least, it can feed into neurosis. You don’t even need to be diagnosed with an eating disorder for this to happen—let’s take, for example, me. My adventures with fasting began a few years ago when I did a few 36-hour fasts, which were prompted by hypochondria. I’d just met my now-wife, and I immediately became convinced I was dying of cancer, due to transient aches and pains that were obviously just side effects of acid reflux. 

This time, I’m not fasting for such obviously insane reasons. But it’s still profoundly weird that I’m doing this, in the same way that lifting weights is weird. Lifting is weird, right? Post-industrial life has forced us to sit and stare at spreadsheets all day, an act which destroys our bodies, so, in response, we have to go to stinky buildings and throw metal around. To mimic our ancestral condition, in which manual labor was a matter of course, we have to do something our most distant ancestors would probably never do—fashion things that are difficult to lift, at great expense, so we can experience difficulty.

Similarly, though fasting mimics the ancestral environment, our ancestors would never, as a lifestyle choice, embrace scarcity. Scarcity just happened sometimes. Moderation was forced on us. We ate whatever was around, whenever we could, probably without very much thought.

The insane part of post-industrial life is that moderation and resistance is up to us, and this is not easy. Faced with the seemingly infinite varieties of comestible available to us, whether food, drink, or drug, we have to make difficult choices on an ongoing basis. Rather than being simple lifeforms who eat food and move on, we become half-assed philosophers of our fridges, wondering whether the pork chop is moral, whether the Oreo is worth the cost, and so on. These are clearly questions of organisms poorly equipped to handle abundance, questions of minds diseased.

So, I don’t think fasting is disordered eating per se. But I also don’t think that ordered eating is an entirely meaningful concept in this post-scarcity civilization.

Oh, and, also, as for fasting’s performance benefits? Given how prominent fasting advocate Jack Dorsey performed against Ted Cruz, he might want to stop skipping lunch.

Day Seven - Gravy

You have no idea how incredible food is. You just don’t know. You quite simply can’t imagine how a dry, mealy, persimmon tasted to me at 4 AM, when I woke from half-sleep and decided that it was time for calories again, how its stores of sugar were psychoactive, how it brought color back to the world, how even my fluorescent-lit kitchen looked like one of heaven’s antechambers.. You’ve never tasted cashews as I tasted them, richer than gold, boomerang-shaped deposits of life itself. And, four hours later, when I disposed of a chicken-fried steak, the experience waselemental. I’ve never run after an antelope, but I’d like to believe that what I felt was something like my forebears did after they’d pulled a barbecued animal from off the fire, the charred husk of what was recently a charging, wild, and lethal life-form, and put it to their lips. The grease was a gift from a higher power.

And, truthfully, I don’t know how incredible food is anymore. I’m a week out from my fast as I write this now, and I’m already relatively complacent as I enjoy a state of material abundance previously unknown to humanity. My Thai shrimp curry is delicious. But it’s not mind-altering. Once again, I’ve become comfortable.

This, I think, is one of the best arguments for occasional fasting. It shows you what you don’t have. Famine is one of the most common historical experiences; until you’ve felt it, if only briefly, in a sense you don’t quite know what it’s like to be a person. And, until you’ve tasted hunger—ketosis is heavy in the mouth, vaguely fetid in its sweetness—you haven’t really tasted food.

After this experience, I’ve decided to fast quarterly. Seven days is kind of excessive; I think I’ll generally stick to three days. That’s probably enough, at the very least, to make any steak into the best steak that’s ever existed.

-Sasha Chapin