The Code That Keeps You Alive and Is Now Being Written Into Machines

Autophagy is what happens when life tidies up after itself.

Cells digest their own debris, breaking down used proteins and faulty organelles to create something new. It’s a biological paradox: destruction as the price of renewal. The word itself means self-eating, coined long before anyone could see what that actually looked like, the quiet machinery of death and recycling built into every living thing.

The process was mapped most clearly by Yoshinori Ohsumi, who discovered that even something as simple as yeast carries the blueprint. His experiments in the 1990s identified a family of genes, Atg, that act like an internal waste-management system. When a cell is starved, these proteins assemble to form a double membrane, a microscopic stomach, that swallows broken parts and digests them back into raw material. In other words, your cells eat themselves to stay alive.

For most of us, this cycle happens unnoticed. It hums away in the background, removing damaged mitochondria, misfolded proteins, and the random detritus of living. Without it, we age faster, fall apart sooner, and die uglier. When it works, it’s a kind of microscopic asceticism, controlled self-denial at the cellular level, with each cell deciding what can be sacrificed for the whole.

Scientists have spent decades working out how to turn it on and off. The main switches are two opposing proteins: mTOR, which says grow, and AMPK, which says survive. When food is abundant, mTOR rules. When nutrients run low or energy dips, AMPK takes over and flicks the autophagic switch. The cell stops building, starts cleaning, and waits out the storm. The same principle applies when we fast or exercise, we trigger our own internal recycling system.

It’s not just maintenance; it’s evolution’s insurance policy. A species that can digest itself without dying doesn’t just survive scarcity, it thrives on it. That’s why calorie restriction, intermittent fasting, and compounds like resveratrol and spermidine are studied as “longevity mimetics.” They mimic hardship in a world of excess, fooling the body into survival mode without the famine. Biohacking through deprivation theatre.

But autophagy isn’t always a saint. In diseases like Alzheimer’s or Parkinson’s, the process breaks down, misfolded proteins pile up faster than the system can clear them. In Type 2 Diabetes, too little autophagy causes inflammation and insulin resistance, but too much kills pancreatic cells. In cancer, the contradiction becomes pure theatre: the same process that prevents tumours from forming in healthy cells later helps established tumours survive chemotherapy.

It’s a biological double agent, a system that can cleanse or consume, heal or harm, depending on timing and context.

That’s where the metaphor sharpens. Because humans, for all our supposed sophistication, are now building our own synthetic version of autophagy, across every system we touch.

You see it in machines that learn to optimise by deleting redundant code, in AI models pruning their own neural connections, in corporations “cutting inefficiencies” that happen to be people, and in governments running “reforms” that sound suspiciously like dismantling.

Autophagy has become a philosophy, one that’s moved out of the petri dish and into our economic, digital, and social structures. We call it streamlining, sustainability, or the new efficiency. But it’s still self-eating. Just scaled up.

Everywhere you look, systems are devouring their own weak parts to appear stronger. Legacy institutions purging departments to hit quarterly targets. Algorithms cannibalising the internet to train better algorithms. Even social media runs on this principle, users feeding on content created by other users, endlessly recycling outrage and novelty until only noise remains.

The irony is that we now admire this recursive hunger. We build machines to copy it. Neural networks, the crown jewels of AI, operate on adaptive pruning: strip away the irrelevant, compress the signal, discard the weak. The result is a machine that constantly refines itself, a kind of synthetic metabolism.

In a strange way, Ohsumi’s discovery gave us more than insight into biology. It handed us the template for the self-correcting civilisation. The dream of an organism, or an economy, that needs no external saviour because it can always eat its mistakes.

But there’s a catch.

In the lab, when autophagy runs unchecked, the cell doesn’t live forever, it dies faster. The recycling never stops; the line between renewal and annihilation blurs. The cell begins to digest essential parts of itself in pursuit of purity. The same thing happens in our world when optimisation becomes religion, when every inefficiency must be cut, every redundancy eliminated, every “unproductive” thing reclassified as waste.

Autophagy works only because it stops. It knows when to stop.

We don’t.

Our machines now simulate intelligence by consuming human knowledge faster than we can produce it. The models we build are trained on our own creative detritus, our words, images, thoughts, feeding back into themselves until the signal starts to degrade. The system is growing more efficient but less original. Just like an ageing cell that’s forgotten what it was meant to be recycling.

Meanwhile, the wellness industry has seized on autophagy as a lifestyle, fasting apps, biohacking supplements, corporate detox retreats. People are starving themselves to trigger molecular processes they barely understand, chasing microscopic immortality while the macro world burns. Humanity trying to cleanse its cells while the planet suffocates on the waste of its progress.

The truth is, we’ve taken nature’s survival mechanism and made it our operating system. Self-cannibalisation as a model of improvement. Delete what’s inefficient. Recycle what’s useful. Never rest. Never plateau.

Autophagy is life’s built-in humility, the admission that decay is unavoidable, so you might as well make use of it. We’ve reinterpreted that humility as ambition.

The more we imitate nature, the further we drift from its balance.

The next generation of AI will probably be fully autophagic, models that continually retrain on their own outputs, endlessly refining themselves in a feedback loop that looks intelligent but is really just iterative hunger. And if that sounds familiar, it’s because it’s what we do: a civilisation eating itself in the name of progress.

Autophagy is proof that life survives by dying in parts. But even the cell knows that the feast must end. The lesson isn’t to cleanse without limit, it’s to recognise that too much renewal is just another form of decay.

And if humanity ever forgets that, evolution has already written the punchline in its smallest script.