Much food goes to waste, which squanders resources and adds to greenhouse gases

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By Nina Shen Rastogi
Tuesday, June 15, 2010

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 the resources used in producing and shipping a foodstuff -- resources such as fresh water and fossil fuels -- are wasted. In addition, edible matter that has been tossed and 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 into the trash. The problem is, there just hasn't been much research into this question.

The 40 percent figure that you mentioned comes from a 2009 report that was one of the first peer-reviewed papers in years that tried to assess food waste on a national level. That statistic is not a measure of how much food individual Americans throw out -- such as 40 cents' worth out of every dollar spent, or five eggs from every dozen. Instead, it refers 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 at the National Institute of Diabetes and Digestive and Kidney Diseases, part of the National Institutes of Health, began by tallying up how much food, expressed in calories, per person -- was available for human consumption in the United States in 2003. Then they estimated how many calories the average person ate that year. The difference between the two figures -- roughly 1,400 calories 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 calories to 40 percent. But since the study is a top-down, holistic snapshot, 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, researchers from the U.S. Department of Agriculture estimated that, in 1995, 91 billion pounds of food -- or about 26 percent of all the edible food available for human consumption -- went missing in the nation's 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, the group concluded that British families throw out 22 percent of the food and beverages they buy to eat at home -- just over 13 pounds 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. A little more than two pounds per home is "unavoidable waste" (stuff such as apple cores and eggshells) and another kilogram is "possibly avoidable" (things that some people eat but others don't, including 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! 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 by sending them to the Lantern at 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 Read previous Green Lantern columns here. The Green Lantern thanks Jonathan Bloom of for his assistance with this week's column.

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