The Real Reason You Shouldn’t Swallow Your Gum

Rumour has it that if you swallow chewing gum, it will stay lodged in your gut for seven years — a bezoar minus the magical poison-curing properties. Of course, as we’ve told you before, this isn’t true. But that doesn’t mean you have licence to swallow your gum willy-nilly — or spit it on the ground, for that matter. The only place gum should go is in the trash, because it’s absolutely terrible for the environment.

This topic is on my mind because of a question that came up in the comments of a recent post about how to know if you’re an arsehole. A reader wondered if their spouse was right in ragging on them for spitting gum on the ground, because what’s the harm? It’s biodegradable, after all. Except it isn’t.

We put it in our mouths, but it isn’t food — gum is made for a synthetic material called polyisobutylene, which is also used to make inner-tubes. It doesn’t break down in your stomach, and it doesn’t break down in the environment. As How Stuff Works put it, “once gum is made, it is gum forever.”

Don’t spit it out

People chew a frankly ridiculous amount of gum every year — around 300 sticks on average in the U.S., our churning jaws powering a global industry worth $US19 ($26) billion. Lots of those sticks probably end up squished on the street or spat into the dirt. Why is this bad? Think of gum like discarded plastic: difficult or impossible to recycle, and likely to be sitting around for a long time wherever it lands. If you spit it on the street, it will stay there forever unless someone cleans it up. Cities spend a lot of money doing just that — according to an interview in The Atlantic with documentarian Andrew Nisker, director of the film gum exposé film Dark Side of the Chew, the UK spends some £56 million ($101 million) every year cleaning it up; in the US, more of those costs likely fall on property owners. Have you ever walked around a city and noticed weird black splotches all over the footpath? That’s residue from old gum. As Nisker states:

Modern gums are made from synthetic polymers, basically plastic and artificial rubber — and they are non-biodegradable. … Gum was once made from natural substances, which microbes could help biodegrade. But modern gums don’t offer them the right habitat to do their thing. … So to clean it off the streets, you need to blast if off with loads of hot water and steam, plus some chemicals to help break it up. It’s time consuming and it costs money.

Beyond the matter of beautification, gum is bad news for birds; if they ingest it, it can be fatal — which isn’t great considering bird populations are already shrinking rapidly across North America.

But don’t swallow it either

But that’s spitting it on the street. Why can’t you swallow it? While it’s true that it won’t lodge in your stomach, that means it will come out, undigested, in your poop. And poop-covered gum is, you guessed it, still gum. Assuming it doesn’t build up and lead to a blockage in your own pipes (resulting in a hefty repair bill), it can travel to your local sewage treatment plant, where it can really, er, gum up the works. Because it doesn’t dissolve in water, gum can cling to anything else that’s mixed in with the rest of the sewage, contributing to the formation of those evocatively named “fatbergs” that cause so many headaches for local municipalities.

Wrap it up

The only way you should ever dispose of gum is to put it into the trash. Sure, it will sit in a landfill forever — with all of our other non-biodegradable crap — but at least you won’t be ruining the environment or killing a bird when you do it.