These Researchers Dug Through People’s Garbage to Find Out Why We Waste Food

Two new studies explore what food gets wasted, by whom, and why—with surprising findings that could guide your next move in the kitchen.


Food waste is a huge problem in this country. It’s also still largely a mystery to many of us. For this reason the Natural Resources Defense Council (NRDC) recently sent a team of researchers out to literally dig through people’s trash.

The organization conducted 277 “household bin digs” (specific audits that involved separating food into 10 different categories), asked participants to keep kitchen diaries, and conducted detailed surveys in three different cities—New York City, Denver, and Nashville—to paint a more detailed picture of food waste than we’ve ever had. Their findings, detailed in two reports published last month, are enlightening.

In Denver and New York—where the data showed people often buy groceries but then don’t prepare food from them—households wasted the most food, followed by restaurants and caterers. In Nashville, residents and restaurants were just about tied. In all three cities, coffee, milk, apples, bread, potatoes, and pasta were among the top 10 most-wasted, still-edible foods; chicken was also up there.

The researchers also got into people’s heads a little bit, and found—echoing the results of prior research—that more than half of people felt less guilty about wasting food if they composted it. And a whopping 76 percent believed they throw out less food than the average American.

One of the most surprising findings is the fact that respondents who understood what a significant problem food waste is were no less likely to waste less food.

Civil Eats discussed these and the report’s other surprising findings, as well as where to go from here, with Dana Gunders, NRDC senior scientist and author of The Waste-Free Kitchen Handbook.

Can you talk about why NRDC set out to do this study?

When I started working on this issue, one of the most frustrating aspects was, and continues to be, that there’s not very much data on it. We have not been able to answer basic questions like: Why are people wasting food in their homes? Or who are the biggest generators of wasted food in a city? Or can a lot of that food be donated?

How did the data you came up with compare to the widely shared estimate that 30 to 40 percent of all food in the U.S. goes to waste?

Dana Gunders

Dana Gunders.

[Other research has found] consumers [generate] the biggest chunk of waste, and we are finding that as well. I think this has validated some of the biggest-picture assumptions that were out there before—and gives us more specifics. For instance, the USDA research lumps all consumers in one category, and it kind of combines restaurants with households. This report gives us a little bit more resolution on something like that.

We’re careful, though, about extrapolating these numbers. For instance, we found that about 3.5 pounds per person per week was wasted across the three study cities, but that’s in three urban environments. We’re careful not to extrapolate that out to the entire U.S. population.

Two interesting findings I don’t think were demonstrated before are: Smaller households are producing more food waste per person than larger households. We also did not find a relationship between income level and amount of food wasted. (It doesn’t prove that there isn’t one.) We’ve often operated under the assumption that when food is a larger portion of your budget, you’re more careful not to waste it. The lack of correlation there opens an opportunity to help those with lower incomes waste less food and stretch their food budget further.

Did you find any seasonal patterns to how people waste food?

This research was just a snapshot. We spent a lot of time creating a methodology and template so that this research can be replicated. We decided to look at the city scale, in the hopes that other places could replicate it and over time we can start to have more information on what’s happening around the country—in different seasons, and in rural and suburban areas.

It’s been found before that people feel less guilty if they compost their food waste, rather than trash it. Is that justified?

If you look at the EPA’s food recovery hierarchy and the general reduce-rescue-recycle frame, composting is a great thing to do with food that can’t be eaten. But it’s not the best use. We certainly don’t want to be putting all the resources into growing food, transporting it, getting it to our table, and cooking it, just to compost it.

Composting does have a very real, clear benefit not just of reducing methane in landfills but also recycling nutrients and offsetting the need for some other fertilizers, which has a big greenhouse gas benefit as well. The messaging is tricky. We want people participating in composting programs, absolutely. Yet we don’t want them to be flippant in the way they’re managing food. You could draw the analogy to [the question of whether to] use a reusable water bottle, or is it okay to use a plastic water bottle just because you’re recycling it?

Do we know why things like bread, pasta, milk, and apples are wasted so often?

It’s all conjecture, but I have a few guesses. One is that [they] are just commonly eaten foods. When you’re doing a study with 600 people, not all of them eat cottage cheese, but they all eat pasta, and they all drink coffee. Frankly, I was surprised that those were at the top of the list. Before the study results, I would have guessed that we use up quickly those routine foods like coffee or milk; my gut tells me it’s foods we do not buy regularly that often go to waste in our kitchen. That’s not reflected in these results, but it may just be that those unusual things are not showing up on the list [because they’re unusual].

What else surprised you in the report?

I was surprised by just how much food thrown out in [homes] was edible. Over 50 percent of what people are throwing out is completely edible food.

I was a little surprised that prepared food was the number-two thing on the list, and that so many people just don’t feel like eating leftovers. However, that’s a pretty straightforward habit to start addressing: If you don’t like to eat your leftovers, then you’re making too much, so let’s help people make the right amount for themselves. Or if you do like leftovers, can we help you freeze them, or not forget to take them to work, whatever it is?

We just released a portion calculator—we’re calling it the Guest-imator—meant to help people over the holiday period plan their portions a little better.

The second report focused on the donation potential, but treating food waste as food assistance is a bit of a fraught issue. Is the ultimate goal to prevent food waste to begin with, or to ensure that more of what’s wasted reaches people who lack food security?

In my ideal world, we would have a system so efficient that we don’t have surplus—and where we design from the start how to make sure people have enough food—not provide food assistance in a way that’s sort of happenstance. That said, we’re very far off from that, and we have so much surplus food that it feels like a better use of it to provide immediate food assistance for people than not.

In Denver, we looked at how much food is not being rescued, how much of the meal gap it would address, and how much it would cost if it were. [The report shows that an ambitious but realistic 901 additional tons could be rescued to close almost 10 percent of the meal gap, costing about $2 million. The full—but more hypothetical—potential would rescue more than 4,000 tons to close 46 percent of the meal gap, with an estimated $6.2 million price tag.] The ongoing capacity to rescue food has a much larger price tag than the initial infrastructure investment.

We’re trying to enable that funding to appear, and also highlight that it’s not free. A lot of the institutions that are accepting and redistributing rescued food need staff capacity. They currently rely on volunteers, and we can’t just assume we can dramatically increase food rescue without a paid workforce to do it.

The research also mentions some cities that have been testing innovative waste prevention strategies. Can you talk about some of those?

The Waste Not OC Coalition is a project in Orange County, California, where they have gotten fairly creative with how they rescue food, including using Yellow Cab drivers to transport it. There’s a case study of the Daily Table, a project started by the former president of Trader Joe’s, that’s basically a low-cost supermarket in Boston. Another is the Drexel Food Lab in Philadelphia; they’re taking products that are often difficult to donate and creating recipes that make them easier to donate. For instance, bananas get really brown, but if you just blend them up and freeze them, it makes them easier and they can be the base for smoothies or banana oat bars or whatever.

How do we connect awareness about food waste with behavior change?

People are aware it’s a problem globally, but they don’t think it’s their problem. We need to think of creative ways to have people wake up to what’s occurring in their own homes, and take some ownership rather than treat it as a problem they don’t have to think much about.

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  1. Sunday, November 19th, 2017
    This concrete beneficial study is a great way to approach how to start making inroads to solving the huge issue of wasting food.

    I would be one of the first to apply for a paid position in a future "food rescue" program. My job title: Social Worker Agent in "Food Rescue."
  2. Mel
    Thursday, November 30th, 2017
    If Bunny Bread would make half loaves of their plantation bread, I wouldn't end up giving as much to my chickens. Also, if the standard number of servings in recipes was reduced, that might help prevent some people from cooking too much at once.