Here’s what happened when I didn’t eat for prescribed periods of time: it affected every cell in my body, and my mind started working better. I can’t prove any of this. There’s science out there that might explain it, but that work is far from settled.

A few times in my life, I have experienced a state of mind that felt “right.” But I didn’t know why or what specifically caused the mental clarity, acuity, focus, and sense of well-being until I began fasting. Each time I did so, I found the same result until I came to understand that not eating and thinking straight were, for me, in some way connected.

I usually tell strangers the same story when I’m trying to sell them on fasting: I’ve been playing classical guitar for more than forty years. There have always been pieces from the more advanced repertory that I couldn’t play no matter how much I practiced. My hands simply were unable to do what my mind wanted them to do.

The work of Argentinian guitarist and composer Jorge Morel is one of the better examples of music I could not play. I couldn’t get the syncopation into my hands. Beyond that, it was just very complex. A few of the adaptations of Bach Lute Suites were similarly beyond my musicianship.

On the fifth day of what’s called a fast-mimicking diet protocol, I was suddenly able to play one of the no-way pieces by Morel. I didn’t need the sheet music, which was weird because I hadn’t memorized the piece. It was by no means concert-ready, but there it was in my hands and my mind simultaneously.

I hadn’t been practicing more than usual when I had the breakthrough, and it had been a while since I had tried to play this particular piece of music. While on that diet I found the Bach was much more accessible—again, having acquired the ability to sight-read them at a decent tempo seemingly out of nowhere. I didn’t suddenly become more talented. Yet now I could play “Danza Brasilera,” and it seemed to be the result of the fasted state.

I first stumbled onto the brain-modifying effects of fasting in 2010, when I almost killed myself doing a drastic fast shortly after observing a severe intermittent fasting protocol—about two hundred calories after sundown—for the entirety of Lent.

It was the second of two fasts for a book proposal I was working on called After the Rapture Can I Have Your Car? Obsessed with the contradictions embodied by the Christian right, I wanted to write a book based on the premise that a true believer in Jesus the protosocialist (someone from the Daniel Berrigan wing of Christianity) had a better shot at de-weaponizing America’s version of the Taliban than the nail-clipper disquisitions of the “Mere Atheism” camp (Christopher Hitchens, Sam Harris, Richard Dawkins, Bertrand Russell, Baron d’Holbach).

So I had a reason for fasting. There was a point—then a seizure, and then I lost consciousness. I suffered a stunt-writing accident. My trying to piss in the wind without getting wet was not without self-irony. I knew the project was ambitious, and a dead end was likely. And that’s precisely how it played out.

But just off the cul-de-sac of my anti–Christian right folly there was an opening. It was barely discernible, a sort of trailhead. There had been a subtle shift in my state of mind during those fasts. I was certain something had happened, but everything I found on the subject of fasting and consciousness came from alternative health sources and lacked rigor. There was no corroborating scientific evidence on the psychological impact of being in a fasted state.

Recent research produced by the ongoing longitudinal Whitehall II study, published in June 2017, would have been useful at the time. It delivered persuasive evidence that diet can play a significant role in depression and other common mental problems, and that they were correlated with sugar consumption. Other recent studies linked systemic inflammation—specifically the blood markers caused by excess carbohydrate intake—to age-related cognitive impairment and Alzheimer’s disease.

Meanwhile, a handful of scientists have begun to explore the relationship between caloric intake and psychological problems. Some scientists are even looking at the possibility that calorie restriction and intermittent fasting may ease the symptoms of depression.

So far, the documentation of the effect food intake may have in the treatment of mental illness is scattershot and unlikely to win anyone a Nobel Prize anytime soon. What science there is seems to suggest that various fasting protocols could be a powerful treatment for a variety of mind-related disorders.

This research springs out of study focused on cell metabolism, health, and aging. One of the most palpable results to arise from this research is that health care practitioners are now more likely to talk about health span rather than lifespan. The trend springs from a growing body of research that humans can maintain their cognitive powers much longer than previously thought and stay healthy much deeper into the woods of old age if they stay away from foods that cause spikes in blood glucose—and, with that, higher insulin levels—mainly by avoiding comestibles with high carb counts. Biohackers pinging off this research have posited that the specific approaches to caloric intake can not only preserve but actually improve cognition.

The unifying theory in most of their research is that metabolic derangements—characterized by the aforementioned spikes in blood sugar, caused in turn by what and when we eat—trigger the chronic, systemic inflammation that gives rise to a murderer’s row of ailments associated with aging, including cognitive decline. The narrative these scientists have been telling hinges on metabolism at the cellular level, especially as it affects the health of mitochondria and a few systemic markers of inflammation.

Depending on caloric intake, cells can do one of two things: replicate or go into repair mode. When feeding decreases, especially during a fast, cells enter repair mode. First, they use up all available energy stores, and then they start general housekeeping—by way of apoptosis (programmed cell death) and autophagy (the cell’s self-composter). The result of this repair mode is not merely weight loss; that’s more of a perk.

Regardless of the current unknowability, I do wonder if derangements at the cellular level may trigger psychological disorders and/or exacerbate existing ones.

I now firmly believe that the Black Fast was the way all this anti-inflammation diet stuff was done prior to the tenth century, at least among followers of a certain anti-establishment rabbi executed at the beginning of the Common Era.

Observed during the forty days of Lent, a Black Fast consisted of one small meal a day eaten after sunset. Meat, eggs, oil, butter (or any other fat), cheese, milk, and booze were all prohibited. In some traditions, the strictures tightened further during Holy Week, allowing only a small amount of bread with salt and water. Other traditions where the Black Fast is still observed—mostly Eastern Catholicism and Classical Pentecostalism—permit no food or water for up to three days. I did the Black Fast both ways.

During the first trial, I had one meal a day after sunset for forty days. It was a small bowl of lentil soup. I broke the fast on Sundays, eating a full meal after church per instructions from the priest I had consulted. I also kept the Daily Office, observing the canonical hours with set prayers and readings (all part of the out-Christianing the Christian right shtick).

After a few days, I found myself on that trail I mentioned. The clanking in the clothes dryer of my soul had ceased. I felt a calmness unlike anything I’d ever experienced. My mind was clear. There was little in the way of mental chatter, and I could do rudimentary math with an unprecedented level of success given my general innumeracy. I was more focused when playing the guitar, but the doors to Morel and other hard-to-play works were still locked. Then Easter came, and I went back to eating like everyone else.

I was sad about that.

I’d finally discovered a semblance of mental clarity, focus, and psychological normalcy, and it required starvation. But neuroplasticity—specifically, activity-dependent plasticity—is a wondrous thing. New experiences create new channels in the mind. A growing body of work in neurobiology postulates that new experiences and states of mind achieved—no matter how briefly—change us fundamentally, actually rewiring the brain.

That was my experience. When I started eating again, my brain didn’t completely revert to its bumptious, innumerate ways. But that didn’t matter to me—I wanted nirvana. I wanted to get back on the trail I found at the dead end of that anti–Christian right book proposal.

If severe calorie restriction improved my mind, zero intake might fix it for good, I reasoned. I decided to try the stricter version of the Black Fast but allow myself a little water, because the possibility of dying looms around the fourth day without food and water.

By day three, I was in a pure meditative state. That said, I had almost fainted quite a few times (fairly common during a water fast if you aren’t used to it). “If you aren’t used to it” is an important qualification, because while I never feel faint now, before my body adapted to running on lower blood glucose, it was common. Other than that, I felt okay and was being careful when I moved around. I felt adamant. The privation was worth it. Fasting was allowing me to win the staring match with what I have come to think of as my own personal mental derangements for the first time in my life. I had discovered that it was possible to consciously starve them out.

On the morning of day four, I got out of bed too quickly and was hit by what at first seemed like a garden-variety case of orthostatic hypotension—that is, a head rush. Knees bent in what probably looked like a junkie’s nod, I tried not to faint. Then my teeth chattered so hard I thought they were going to shatter, and then the convulsions started. I hit the tile floor pretty hard and head first. It was a bit of a blur, but I remember thinking, right before I lost consciousness, that I had finally gone too far: I was going to die.

I doubt I was unconscious for a long time, but at some point I woke up with a knot on my skull. I’d placed caches of food around my apartment before going to bed. I immediately broke the fast with one of them—a changed man, although I didn’t know it quite yet.

I had been half-shovel sane most of my life, a high-functioning neurotic. Ruled by a parade of brain and/or psychological disorders (it’s hard to know which), my moods were unpredictable. What I didn’t understand was the possibility that at least some of my issues might be cellular in nature. I lived on sugar as a kid. It would make sense that the cellular derangements caused by that kind of calorie consumption could in some way be manifested in the psyche. (To be clear, since the science is still in its infancy, I’m talking only about my psyche and my experience of it.)

Over the years, I had called my problem by different names. I made all sorts of reference-library and, later, Google diagnoses ranging from clinical depression, ADHD, and substance dependence to short- and long-term memory loss (due to substance abuse and trauma), PTSD, and, perhaps more than anything else, something that was nowhere to be found in the Diagnostic and Statistical Manual of Mental Disorders—a kind of shape-shifting melancholy with the look and feel of something fixed and unfixable.

While I’ve read quite a bit about neuroplasticity, my thoughts were gestural, and by that I mean that the position I’m going to sketch out here is my own invention. Simply put, if good experiences can rewire the brain, bad ones can do it too, embedding themselves in how the mind functions. That was the starting point. A crisis changes the mind, so only another crisis—such as fasting—could change it.

My mother died in 1986. It’s a good place to start because it wasn’t the result of ingesting anything, and it played a major role in the way my mind works. To my way of thinking that gave rise to a cellular situation, but it wasn’t the manifestation of a great crisis but was rather more like an effect. As such it was powerful enough to slide me between the sheets of a hospital bed on the first anniversary of her death. That experience, too, changed the way my mind worked.

When I was an allegedly dangerous teenager (if I ever was one), some country doctor decided it was wise to tie me down and feed me tranquilizers because I had halfheartedly thrown an ax at someone on the first anniversary of my mother’s death. At least I think that’s what happened. What I remember most is the very Vermont-seeming nurse with the unfiltered Pall Mall cigarette between her fingers, holding it to my mouth like it was a straw. That definitely changed the way my mind worked.

“So long as you’re not going to hang yourself.” That’s what the man at the hardware store had said to me around the same time. I smiled. He smiled back. It was an awkward moment for both of us, because that was clearly the only reason a skinny eighteen-year-old in full post-punk, late 1980s grunge mode would buy twenty feet of rope on a weekday afternoon. That transaction changed my synapses, too.

Sane or insane sometimes depends on where the volume is set on your soul. I was pretty good at making thoughts of self-murder go away by drinking, having sex with strangers, doing drugs, petting a dog, or going on a long walk. When I couldn’t make that kind of thinking go away, I bought rope. Suicidal ideation was an effect or perhaps a manifestation of something that was occurring at a cellular level, and it too left a mark. I refer to the above as “derangements” because I believe they mirror the types of metabolic derangement that occur at the cellular level.

My story includes many other so-called derangements, and I would argue that all of them changed the way my mind worked. Things seemed darker than they actually were, and that made it harder to maneuver through daily life.

Years later, what is perhaps my most notable derangement had me driving drunk the wrong way on Eastern Parkway in Brooklyn with my daughters, aged four and six, in the back seat. That derangement cost me the publishing house I owned, six jobs in six years, and a marriage, and it still had the audacity to try and finish me off on the floor of my kitchen after I ingested an ornate and nearly lethal cocktail of drugs and alcohol. That manifestation of my derangements very much was a cellular thing, however, and if it didn’t change I was going to die.

It’s been seven years since the Black Fasts, and almost ten years since that big sleep on the kitchen floor. Present tense: relax. I’m better now, clean and sober—all that. I’ve tried different forms of caloric restriction over the years to attain the state I found myself in during that first Black Fast.

I usually do some kind of fast every month, sometimes with little in the way of mental changes but occasionally with notable psychic shifts on the order of something plate tectonic. It’s easier to water fast for three to five days than to mess around with calorie restriction or intermittent fasting. I eat no grains, no root vegetables, and nothing with sugar in it, including most fruit (the main exception being avocados and the occasional tomato). This past fall I had one Honeycrisp apple and it gave me such a sugar rush I felt like I had just met God. These days, I’m almost always in a state of nutritional ketosis, a mostly fat diet originally developed in the 1920s to treat childhood epilepsy. It features limited protein and very little carbohydrate, and I have found that it has pronounced positive effects on mood and mental acuity.

I had tried to fix my own derangements with varying degrees of success—whether they were inborn or pocks of life on life’s terms—by drinking to excess, abstaining from drink, ingesting various psychedelic drugs, sleeping, not sleeping, reading, not reading, smoking pot, not smoking pot, obsessing about unrequited love, looking for true love (online, at work, on public transportation, in books), learning transcendental meditation, going to church, not going to church, studying breathing rituals, attending AA meetings, avoiding AA meetings, rescuing animals, seeking gurus, and many other schemes. But it was my friend Frank who finally got me pointed in the right direction.

Frank Butler practices Chinese medicine. I’ve seen him for years, and he was the one who first explained cellular derangements to me, although I’ve no doubt mangled his nuanced understanding of the kinds of cellular situations that give rise to disease. He said science was finally catching up to things Chinese medicine always knew, and I guess I was predisposed to believe him because I’ve seen Frank do miracles in his practice.

When I told him I was experiencing greater mental acuity during fasts along with a settling of age-old issues, he told me about a diet protocol prescribed for thousands of years by Chinese doctors: a cup of steamed vegetables twice a day for mental focus—maybe two hundred calories. It was sort of a second cousin twice removed from the Black Fast.

I embarked on a five-and-a-half-day water fast during the holiday break. As mentioned earlier, the effects can vary. This time something truly amazing occurred. I entered the fast worried that it might impede the various obligations and tasks associated with the season, but there was none of that. I even managed to get my dog to urgent care on Christmas Eve after he ate something repulsive in the street, still do some last-minute shopping, and wrap presents. And while almost everyone has a visceral reaction to the sight of a person downing a shot glass filled with almonds and olive oil (a go-to fuel source for me), no one ever seems to notice when I’m fasting. My mood either improves or doesn’t change, and not eating is tough to spot.

Acquiring agency in the estuary of the kinds of metabolic and/or mental derangements discussed here is a slow process. Achieving a state where fasting becomes easy requires months of metabolic adaptation, and you should not try any of the protocols discussed here without professional guidance, blood tests, and preferably someone who is willing to respond to your panicked “What now?” texts. (Thank you, Frank.)

On this fast, it was as if a huge part of me were missing. But it wasn’t anything I needed. I could think; I had recall; I could still play Jorge Morel in that completely mediocre way that happens among players who don’t have enough time to practice. My mind was clear. But the clarity was far beyond anything I’d come to know through meditation. The closest corollary I’d ever felt was during the recovery days following a very large dose of LSD. There was a marked absence.

When I told Frank about the extraordinary quality of this fast, he nodded. He’d had the same experience. “It’s an absence of anxiety,” he said. He was right, but it was beyond mere absence. It was like the part of the mind that houses anxiety was gone. All signs seemed to point to the annihilation of self, especially this newfound lack of anxiety. No self meant nothing to worry about.

A single cell is always faced with a choice, based on caloric intake, between replication or repair. Replication doesn’t require an explanation, and it has obvious psychological corollaries. The repair mode is trickier, but the key is that process called autophagy, when the cell cleans house. Perhaps the unfed mind engages in a similar kind of housecleaning.

Read more on the mind in our Winter 2018 issue, States of Mind.