Canadian documentary filmmaker Andrew Nisker's first film was about the garbage in his household. His latest film is about another kind of garbage: gum. Dark Side of the Chew started when Nisker read that chewing gum is the second most-common form of litter (cigarette butts are number one at 1.7 billion pounds a year). He decided to look into both the history and the present-day economics of gum: It turns out that chewing gum dates back thousands of years, and today costs millions of dollars to clean up.

I recently spoke with Nisker about his new film, and why we should care about gum. A lightly edited transcript of our conversation follows.

Bourree Lam: When did chewing gum first show up in human history?

Andrew Nisker: According to archeologists, humans have been chewing gum for at least 5,000 to 9,000 years. Some evidence comes from ancient gum samples, found in Finland. The gum samples found there are made from birch-bark resin. It’s believed that Neolithic people chewed this gum to treat oral infections, to fix hunting tools, and maybe repair pots. There’s some speculation that they also just chewed it for pleasure.  

We also know that for over a thousand years cultures in the Middle East chewed mastic gum. In North America, First Nations (Aboriginal Canadians) people chewed gum made from spruce-tree sap. In the film, we talk about chicle—a gum chewed by the Mayans and Aztecs. Modern gums are made from synthetics.

Lam: Why do humans love gum so much?

Nisker: There are few reasons. On the most basic level, the sweetness in gum provides us with a bit of an energy boost—because of sugar. If it’s sugarless, we still get an energy boost because chewing gum stimulates the body to expect food, and if we don’t get the expected food our body burns fat to fuel muscles. Also, the very act of chewing activates pleasure sensors in the brain—which helps us to relieve stress.

Lam: What’s the most interesting thing you learned making this movie?

Nisker: One of the most interesting facts we discovered is that gum was one of the first items to be mass marketed by Thomas Adams. The gum company he founded in 1869 is still around today. They make Chiclets!

Lam: What's the size of the gum industry today?

Nisker: The gum industry is huge. It was difficult to get firm figures from the companies themselves, but consensus seems to be that it's over a $19 billion industry.

Lam: How much gum do people in Toronto chew a year?

Nisker: In the film, we tried to figure out how much gum waste people generated in Toronto. We worked with ESRI, a Toronto-based company that uses GIS mapping analytics and photo-mapping software to quantify the amount of gum waste that shows up on the city’s sidewalks. What we discovered is that in an average year, Torontonians generate roughly 2,000 tons—that’s 275 sticks per person. Basically that’s a small herd of elephants.

Lam: So what are the economic concerns of gum?

Nisker: If you can imagine all that gum waste collecting on our sidewalks (not to mention, on our streetcar seats, carpets in public spaces, chairs in classrooms, our hair, etc.) there’s a lot of gross chewed gum sticking around. Most people ignore it in small patches, but where it concentrates it's a blight. Towns and cities in the U.K. are leaders at ridding gum waste—millions of pounds are spent removing gum on London’s streets. Across the U.K., that number is even higher. That’s a lot of money that could go elsewhere. When gum is being removed from public spaces, that’s tax dollars being spent. If it's private business, or business associations, that’s a cost that's being passed to consumers.

Lam: How many millions are we talking about?

Nisker: I don’t have a figure for Canada, but in the U.K. it’s £56 million.  In Canada and the U.S., it seems that the cost falls on local business owners, whereas in the U.K. it's tax money and private funds.

Lam: Why is gum so hard to clean? How is it done?

Nisker: Modern gums are made from synthetic polymers, basically plastic and artificial rubber—and they are non-biodegradable. The very attributes that help [gum] hold the flavor in your mouth make it very difficult to remove when it ends up sticking on the sidewalk. 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. It’s very difficult for any organism to eat plastic. 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.

Lam: What do you think about countries like Singapore, where the government has banned the domestic sale of gum?

Nisker:  That’s a good question that we didn’t have time to explore in the film. But we did the research. Part of their reason to ban gum was the waste issue: It's uncivilized to litter, plus it costs money to clean. So to deal with the problem, they thought it would be easier to ban it. But it’s not a total ban. The gum manufacturers lobbied the government to allow medical gums, so if you have a prescription, you can chew.

Lam: What is medical gum?!

Nisker: Medical gums (or functional gums) are an emerging industry. There’s everything from Nicorette, sexual aid medications—think Viagra gum—to low-dose heart medications that's being prescribed in gum. Gum can be used to release the medications at a slower pace.

Lam: How do you feel about gum after making the film? Is there indeed a dark side?

Nisker: Is there a Dark Side of the Chew? Yes there is. There are questions around gum, such as really understanding what it's made from and how it might impact our health. Besides this, when people improperly dispose of their gum on our sidewalks it costs money to clean up. And not to mention the environmental impact of cleaning it up. We could avert the problem by just being more aware that our habits have larger impacts. Simple solution: Throw used gum in the trash, or chew a natural gum alternatives like chicle.  

Lam: Mouthwash vs. Gum?

Nisker: I’d chew a chicle-based gum if I could find it. It’s not really available in Canada, so most likely I’d just brush my teeth with natural toothpaste.