I've heard that Americans waste 40 percent of their food. Could that possibly be true? That's five eggs from every dozen!
Determining how much food we waste every day can be tricky, but the calculation matters a great deal. Squandered calories mean that whatever resources went into producing and shipping a foodstuff—like freshwater and fossil fuels—are wasted, and edible matter that's left to rot in landfills tends to generate methane, a powerful greenhouse gas. So we really ought to know what percentage of our food output gets dumped down the trash. The problem is, there just hasn't been much research into this question.
The report that included the 40 percent statistic was one of the first peer-reviewed papers in years that tried to assess food waste on a national level. That's not a measure of how much food individual Americans throw out—like 40 cents' worth out of every dollar spent (or five eggs from every dozen). It refers instead to the amount of food lost all along the supply chain, including damaged produce from supermarkets, losses at processing plants, uneaten restaurant entrees, and food that goes bad during transportation.
To make that calculation, researchers from the National Institutes of Health began by tallying up how much food—as expressed in kilocalories per person—was available for human consumption in the United States in 2003. (The raw data came from the U.N.'s Food and Agriculture Organization.) Then they estimated how many kilocalories the average person ate that year. The difference between the two figures—roughly 1,400 kilocalories per person, or about 38 percent of the original supply—represents the amount of food energy lost in the farm-to-fork journey.
The NIH team further concluded that per-person food waste has increased significantly since the 1970s, from about 30 percent of available kilocalories to 40 percent. But since the study is a top-down, holistic snapshot of the issue, it doesn't tell us anything about where the waste happens—or, to speak directly to your question, how much is due to overzealous grocery shoppers or recalcitrant children who fail to clean their plates.
Another widely cited set of statistics sheds light on the consumer end of the issue—though it, too, needs a bit of context. In 1997, a team of researchers from the USDA estimated that, in 1995, 91 billion pounds of food (PDF)—or about 26 percent of all the edible food available for human consumption—went missing in our food-service establishments and home kitchens. (By comparison, a relatively tiny amount—just 5.4 billion pounds—was lost by supermarkets, convenience stores, and other retailers.) The big caveat with these numbers is that the USDA's calculations were based on a limited number of studies from the 1970s; even in 1997, the figures were intended to be only preliminary estimates. The USDA is updating its underlying calculations, so hopefully we'll have some new statistics in the not-too-distant future.
So how much of the food we bring home ends up getting thrown out? One researcher has written that American households toss about 14 percent of the food they purchase, but the Lantern hasn't been able to determine how that figure was reached. In the United Kingdom, the government-funded nonprofit WRAP has conducted extensive studies on the topic. In a 2009 report (PDF), the group concluded that British families throw out 22percent of the food and beverages they buy to eat at home—just over 6 kilograms per household every week. A full two-thirds of that is what WRAP calls "avoidable waste"—i.e., things that were, at some point, fully edible. About 1 kilogram per home is "unavoidable waste" (stuff like apple cores and eggshells) and another kilogram is "possibly avoidable" (things that some people eat but others don't, like bread crusts and potato skins).
Personally, the Lantern has always had a hard time keeping her food waste in check. Like many green foodies, she loves nothing more than spending a Sunday afternoon strolling the farmers market. Ramps! Fiddlehead ferns! I'll learn how to cook 'em all!, she thinks. But during the week, she's too exhausted to cook what she bought—so some of that lovely produce goes bad before the Lantern figures out what to do with it. You can compost most uneaten food, which is preferable to throwing it in the trash or down the disposal, but reducing waste in the first place is the best option of all. Whether you're at the farmers market or the Wal-Mart, buying in bulk often makes economic and environmental sense. But that 20-pack of chicken legs doesn't seem like such a good idea when half of it gets freezer burn and has to be chucked. So what's the best way to keep a fully stocked, varied fridge and pantry without creating lots of unnecessary waste?
That's where you come in, dear readers. This week, we're turning the green advice column inside-out: How do you avoid refrigerator rot and pantry putrefaction? How do you plan your grocery shopping and cooking to minimize waste? Share your tips and tricks in the comments section below, or send them to the Lantern at firstname.lastname@example.org. We'll print the best responses in an upcoming column.
Is there an environmental quandary that's been keeping you up at night? Send it to email@example.com, and check this space every Tuesday.
The Green Lantern thanks Jonathan Bloom of wastedfood.com.