Garbage Can Teach Us a Lot About Food Waste

A novel and slightly gross study aims to fill in gaps in our understanding of Americans’ food waste

What's in here? A new study aims to find out. Pixabay

One man's trash is another man's data.

This month, in a first-of-its-kind study, the nonprofit Natural Resources Defense Council (NRDC) will begin digging through the trash bins of residents and businesses in three American cities. Why? Because it turns out we don't actually know that much about food waste. We know that Americans waste about 36 million tons of food a year, but we don’t know the nitty-gritty details about individual behavior. How much of that “waste” is bones and peels that can’t be reused, and how much is food that could have been eaten? And how could not wasting some of that food help communities provide for the 48 million Americans who aren’t sure where they’ll get their next meal?

The new, slightly gross research will help us to understand the truth behind our communal food waste habits. NRDC researchers want to know not only how much food we throw away in a given week, but also how much of it could have been eaten if we had planned better or ignored an erroneous expiration date.

Starting in Nashville, Tennessee, the team will ask hundreds of volunteers to keep a weekly kitchen diary about what they throw away, and why. Then they’ll return to dig through their trash bins—Hazmat suits and all—to see if the diary matches the deeds.

The same work will begin in Denver, Colorado, a month later and in New York City in January, to get a sense of how these behaviors vary across the country. Altogether, researchers will survey about 1,000 residents and 100 businesses.

“This is the first time anyone’s trying to really track and get a better understanding of food waste in U.S. cities,” says Dana Gunders, senior scientist and food waste guru at NRDC, whose groundbreaking 2012 report found Americans waste 40 percent of their food—or more than 20 pounds per person each month.

The Rockefeller Foundation has given nearly $1 million to fund the project in hopes that it will give cities and citizens tools to chip away at their piece of the food waste pie. The Environmental Protection Agency set a goal last year for Americans to cut food waste in half by 2030—which in turn would cut water use by 25 percent, save consumers $165 billion a year, and reduce methane emissions from landfills by 20 percent in the process. But many cities are still grappling with how to reach that goal.

After funding the agricultural Green Revolution that helped feed a billion people, the foundation sees too much of those production gains being wasted today.  

“We really believe there’s a very strong common interest emerging, from the household level up to major corporations, where people want to know what to do,” says Zia Khan, Rockefeller’s vice president of initiatives and strategy. “We’re optimistic that, once we provide this information, lots of innovative people will figure out solutions at different scales.”

Garbage Can Teach Us a Lot About Food Waste
Expiration dates can be confusing to consumers, resulting in wasted food. Ken Tannenbaum/iStockPhoto

This isn't the first time scientists have gone dumpster diving to understand what we’re throwing away. Trash-digging projects of a similar scale have taken place in London and Vancouver, but in those studies, the researchers weren't able to match up bins with food waste journals. Besides, “we can’t assume that we have the same practices as British citizens,” says Gunders.

Cities have also hired “solid waste experts” from companies like Kansas-based Engineering Solutions & Design to sift through their landfills and tell them what could easily be diverted, and scientists at NRDC have done similar work. But those studies typically break the waste into several categories, one of which is “food.”

“What we can’t say from that is: What kind of food was it? Was it edible, or just bones and peels? Why did it happen? And it doesn’t give you any information on how to address it,” Gunders says. 

"The geek in me is actually strangely jealous that I’m not getting to be elbow deep in food waste in Nashville." 

Gunders hopes this study will fill in some of those gaps. We have vague notions about the food waste chain: Imperfect produce is left to rot in farm fields or discarded at the grocery store. Food that was once perfectly good goes bad in our refrigerators or is left uneaten on a restaurant plate. But we don’t know how much of that could have been eaten, and how much was inevitable scraps and bits from processing.

When Gunders looks at residents’ trash surveys and through their bins in the coming months, she’ll be interested both in what’s just “past due” (and technically still fine to eat), and what should have been eaten days earlier before it spoiled. One reason people throw away food is that they might not understand that best-by dates on packages are suggestions, a problem legislation introduced to Congress this year aims to address. The other represents a series of more complicated problems: our ability to match cooking aspirations with reality and our propensity to over-order among them.

One hypothesis Gunders is confident making: people tend to underestimate how much food they’re really throwing away. The average American household wastes about $2,000 worth of food each year, according to Jonathan Bloom’s book, American Wasteland. But a survey conducted last year by the Johns Hopkins Center for a Livable Future found that 75 percent of Americans still think they waste less than the average American.

“It’s like my favorite statistic,” says Gunders. “Everything points to the fact that people don’t know how much they’re wasting and tend to think they’re doing great.”

When researchers dug through trash bins in London and Vancouver, they found they regularly contained more food waste than the average diary had indicated. Those researchers were not able to match specific bins to residents who completed the survey, working off of averages instead. Gunders said NRDC’s work in Nashville will compare diaries and bins from the same homes, though she’s not yet sure whether that will be possible in Denver and New York City.

On the commercial side, the project will work with several types of businesses, from schools and sports arenas to restaurants and grocery stores, to estimate the food each sector tends to waste. Talking to businesses will help them discern whether those sandwiches in the dumpster were uneaten halves from customers, which they can’t recover, or shrink-wrapped extras from the refrigerator, which could have been donated to a food bank.

Each city will get a report detailing how much food wasted by businesses could instead be recovered to feed the hungry. And all this data will be made available for other cities interested in trimming their trash bills or meeting their communities’ needs with food that might have been tossed.  

“What we will have at the end is a decent estimate of residential waste, why and what, and a very preliminary look at commercial waste,” Gunders says. “I expect it’s a first step that people will build off of for years.”

Get the latest Science stories in your inbox.