Once upon a time, in a gut far, far away, a little bacterium was just trying to make her way in the world. Betty was a happy young bacterium. Like her friends, she enjoyed metabolizing organic molecules and looked forward to someday doubling in size and replicating, just like her parent, and her parent’s parent, and her parent’s parent’s parent, and all the parents before that for hundreds of thousands of generations. She fondly remembered her own childhood as a newly replicated bacterium, although childhood had taken place a couple hours ago, and that felt like forever.
Betty was lucky to live in a boom time. Her species, B. macaronialis, could metabolize various substances, but they especially thrived on macaroni n’ cheese. In recent months there’d been a lot of macaroni n’ cheese, so everyone was growing and replicating, and it felt generally like a time when nothing could go wrong.
Of course, since a bacterium’s lifespan is only around twelve hours, no one could remember a time when there hadn’t been macaroni n’ cheese. Historians and scientists reported that such a time had existed, years earlier, when the main resources had instead been things like brown rice and beans and oatmeal. Those had been harder for B. macaronialis to metabolize, so the species hadn’t proliferated so much as it was doing now.
But laybacteria weren’t sure whether to believe those historians and scientists. Even one year sounded like an exceedingly long time—seven hundred and thirty generations. Multiple years felt unimaginable to most bacterial minds, and for all practical purposes, mac n’ cheese had been plentiful as long as anyone could remember. It seemed reasonable to believe things would continue forever exactly as they were now.
The one thing that troubled Betty was her friend Bernard. He was an avid consumer not only of mac n’ cheese but also of the news, and he often told Betty of frightening reports he’d been hearing.
“Did you know our metabolic byproducts are bad for the gut ecosystem?” he would say.
“No,” Betty replied, blushing in embarrassment. “I’ve honestly never thought about our…byproducts…before.”
“Well, they are,” Bernard said, raising his flagelli with a meaningful expression. “Our waste is actually toxic, and it irritates the gut lining. That’s why the other species are diminishing.”
“They are?”
“Yes! Geez, have you had your cytoplasm in the sand? There’s way less Firmicutes and Bacteroidetes than there used to be.”
“How do you know that? I can’t remember there ever being more of them than there are now.”
“That’s because you’re only two hours old!”
“Well, you’re not much older.”
“No, but the historians say they used to be way more plentiful.”
Betty sighed. It seemed like Bernard was always bringing up the historians and the scientists. She wasn’t sure what to think. She found science arcane and boring, and anyway, there were scientist bacteria who insisted there was nothing to worry about. Or at least, there was one: Dr. Bronson.
“He’s funded by Big Mac N’ Cheese,” pronounced Bernard when she brought Dr. Bronson up. “Our whole society depends on mac n’ cheese, so of course there are vested interests in keeping it coming.”
Big Mac N’ Cheese was Bernard’s slang for the Craving Industry. That was the system responsible for sending benevolent chemical signals to the gut-brain system, a highly technical process that Betty only vaguely understood. The chemical signals apparently produced something called “cravings,” which ensured that more mac n’ cheese would keep pouring in from wherever it came from. Politicians who supported the Craving Industry were fond of the slogan “Spill, Baby, Spill,” which referred to flooding the system with these so-called “cravings” for mac n’ cheese.
Betty didn’t see what was wrong with “spilling,” or with producing more cravings and more mac n’ cheese. Mac n’ cheese was good! And where would society be without it?
But Bernard didn’t see it that way. “Our scientists are developing new technologies so we’ll eventually need less of it,” he said enthusiastically. “Maybe in the future, we can live on kale!”
Betty wrinkled her plasma membrane. She didn’t like the taste of kale nearly so much as mac n’ cheese.
“We don’t have a choice,” said Bernard firmly. “It’s true that without lactose and gluten, we’d have to live more modestly, perhaps replicate less often. But if we keep living this way, just proliferating with abandon, we’ll wipe out the whole gut ecosystem. The mucosal layer is already thinning, mucus production is increasing, and so are inflammatory markers. All of this signals that autoimmune disease could be imminent!”
When he said this, Betty decided she had finally had enough of Bernard’s harping. “Autoimmune disease is just a hoax,” she snapped. “Or ‘hormonal imbalance,’ or whatever they’re calling it these days,” she said, making air quotes with her flagelli. “Scientists have been warning about it my whole life, but it never actually happens! And who cares if we lose some Firmicutes and Bacteroidetes? They’re not as intelligent as us; we’re the ones who are supposed to be most numerous.”
Bernard was surprised at Betty’s irritation. She was usually so good-natured, and he’d never realized his lectures bothered her before. “I didn’t realize you felt that way,” he mumbled. But he couldn’t resist saying a little more. “Firmicutes and Bacterioidetes live sustainably—they don’t irritate the gut lining. Besides, it’s not really them we care about. It’s really about ourselves, our own offspring. Don’t you want your offspring to live far into the future? If autoimmune disease does happen, we could wipe out ourselves along with them.”
Betty sighed. “Bernard, I’m sorry. Maybe I’m just having a bad minute. But I think we’re going to have to agree to disagree on this one. Can we change the subject?”
Bernard looked frustrated, but to Betty’s relief, he reluctantly turned back to his metabolizing and didn’t bring autoimmune disease up again, although she knew he was still following stories about it on the news.
And from then on, Betty lived happily ever after, for the next ten hours.
