Quick, look in your refrigerator. If you were to clean it out, how much of it would you have to throw away?

You probably have Tupperware containers of this month's leftovers and probably half a dozen fruits and vegetables that are past their prime. And if you count the remains of last night's dinner stinking up the trash can, you're looking at several pounds of wasted food in your kitchen.

The waste in your home is likely to be repeated in millions of other U.S. households. Then think about every unfinished plate at restaurants nationwide and thousands of buffet lines, grocery stores and dining halls at closing time.

All told, Americans throw out between 25 and 50 percent of the food produced in this country, according to estimates. On the conservative side, that's more than $100 billion in food going to landfills every year.

Wasted money isn't the worst of it, says writer Jonathan Bloom, who blogs at Wasted Food (www.wastedfood.com) and is working on a book about the subject. That food rotting in landfills, because it isn't decomposing with the help of oxygen, is creating millions of tons of methane gas, which scientists say is more than 20 times as harmful as carbon dioxide to our atmosphere. Eighteen percent of what goes into landfills is food, and landfills are the largest human-related source of methane.

"People who grew up after World War II don't value food the same way as those who lived through the Depression, when rationing happened and people had to grow their own food. Wasting food was [seen as] helping the enemy," Bloom says. "The stakes are even higher [today] if you talk about global warming."

Even though there is more food waste at the commercial level, widespread change almost always starts at home.

"In the household setting, people have power to effect change and reduce the amount of food that gets sent to landfills," Bloom says.

It's a matter of breaking habits we've collectively been forming over the past 60 years. Bloom points out that the government isn't seriously studying this issue; the last major report was in 1997 based on data from 1995.

Raising awareness of the copious amounts of wasted food just might be a silver lining of the sinking economy.

"People are paying attention more," he says, especially since food and commodity prices skyrocketed last year. "They want to make sure they stretch [the food] out and get all the use they can from it."

Bloom says about 25 percent of the food we bring into our homes isn't eaten, which totals on average more than 450 pounds a year per household. Estimates are that 15 percent goes in the trash and 10 percent into garbage disposals. By curbing the amount of edible food thrown away, Bloom says families could save hundreds of dollars a year.

"It's easy to discount the impact that you, as an individual, can make," Bloom says. "At the same time, if everyone thought that way, we'd never accomplish anything. Whenever the idea of reducing or composting food waste seems unlikely to catch on, I think of how recycling was a foreign concept 20 years ago."