The average American family of four wastes between $1,350 and $2,275 a year in food.
Much of that ends up in the kitchen trash can: uneaten leftovers, milk past the expiration date and vegetables that go bad.
In the U.S., all that waste adds up to 90 billion pounds of food a year, and the planet is paying a staggeringly high price for it.
"It's not something many people think about, but it takes a huge amount of resources to get food to our plates," says Dana Gunders, a scientist with the National Resources Defense Council.
Uneaten food means that the water and land used to grow the food are wasted, too.
"That's just a terrible use of those resources," she says.
About 24% of all water used to grow crops goes toward food that will be wasted, whether on the farm or in the kitchen, according to the NRDC. The land used to grow this wasted food is roughly the size of Mexico.
Rotting food in landfills creates methane, which is 25 times more potent than carbon dioxide in its contributions to global warming, she says.
Americans typically throw out 21% of their food, according to the U.S. Department of Agriculture. Fresh fruit and vegetables, seafood, meat, milk and eggs top the list of the most wasted foods.
But a worldwide movement is working to change things.
Earlier this month, the USDA and the U.S. Environmental Protection Agency challenged consumers and companies to waste less food. A day later, the United Nations called on people worldwide to reduce their "foodprint."
Even the pope weighed in on the issue, saying that wasting food flies in the face of efforts to feed the hungry. Our "culture of waste" is like stealing from the poor and hungry, he said this month.
So how do you become a nonwaster?
Start by understanding expiration dates, says Jennifer McEntire, a food scientist and spokeswoman for the Institute of Food Technologists. Such dates — including "sell-by" and "best-if-used-by" — don't refer to food safety, but are set by manufacturers who have determined when their food tastes the best.
"Manufacturers will do tests to determine how much time that product can sit on the shelf before it starts to taste a little stale, the texture isn't what the manufacturer wanted," McEntire says.
"Then they build in the buffer and that's the date they stamp on things. They want people to be eating it when it tastes the best."
So those crackers that are a day past the expiration date? They may not taste as fresh as they did two months ago, but they are still safe to eat.
With the exception of baby formula and eggs in California (follow the expiration dates on those), the government does not regulate expiration dates. And it is legal to sell food past its expiration date.
McEntire recommends people pay more attention to dates on dairy and meat, as the likelihood of getting sick is greater than a canned or packaged product, which are often still safe past their expiration date.
Pay special attention to "use-by" dates, but in general, the institute considers expiration dates guidelines, not hard and fast rules.
Other ways to reduce your waste:
Check the temperature. An FDA study found that 27% of refrigerators are warmer than the recommended 40 to 41 degrees. That can make food spoil faster. A proper temperature will make your food last.
Buy only what you need. It sounds obvious, but buying more than you can eat is one of the biggest sources of waste. "We get busy. It's tough," says Ginnie Nash, who manages a nutrition education program at University of California Cooperative Extension.
Plan out your meals on paper ahead of time and see what's in the fridge and the cupboard before going shopping.
Slice up some fruit and stick it in the fridge. Kids are more likely to eat peaches, for example, if they're sliced up and ready to go in the fridge, Nash says. Easy is key.
Stock your kitchen like restaurants do. Meaning: Put the oldest food in the front of the cupboard or refrigerator, the newest in the back, Nash says.
Ask for smaller portions. Some grocery stores, including Whole Foods and Vons, will cut fruit and vegetables in half for shoppers who ask.
Most commonly, Whole Foods shoppers have a watermelon cut in half when a whole one is more than they can eat. The remaining half is sold as is, used by the store's prepared foods department, given away as samples to customers or donated to a food bank.
Start a compost. You're still throwing food away, but it's not going to waste. It's being turned into nutrients to fuel your garden. Composts produce less methane than food rotting in landfills because there is more air flow, particularly when composts are turned, says Gunders, from the NRDC.
Freeze your leftovers. Freeze anything you think you might not use before it goes bad, Gunders says.
If meat isn't going to be used within two days, wrap it in foil, label and date it and put it in the freezer, Nash says. Separating it into family-size portions will increase the likelihood you'll use it in time.
"If we just got in habit of popping stuff in the freezer, that could go quite a long way," Gunders says.
Expiration dates: What do they mean?
Most expirations are set by manufacturers, with the exception of eggs and baby formula.
Sell-by or display until: Tells the store how long to display the product.
Best-if-used-by or best before: Recommends the date to consume the product by in order to experience peak flavor and quality. It does not pertain to the safety of the product.
Use-by: The last date recommended for the use of the product from a food-safety perspective.
Source: U.S. Department of Agriculture
How long will food keep?
Apples: 1-3 weeks
Lunch meat: 2 weeks unopened, 3-5 days opened
Cereal: 6-12 months unopened, 2-3 months opened
Cookies: 2-3 weeks in airtight container in cupboard
Cream cheese: 5-6 days after opening
Eggs: 3-5 weeks
Uncooked poultry refrigerated: 1-2 days after purchase
Uncooked beef, veal, pork or lamb, refrigerated: 3-5 days after purchase
Shredded cheeses: Use within 2 days of "best when purchased by" date
Sources: U.S. Department of Agriculture and U.S. Food and Drug Administration
The reporter can be reached at (559) 441-6431, firstname.lastname@example.org or @BethanyClough on Twitter.