We are wasting up to 25% of our food in the US, according to an article in Scientific American, which says that

According to the U.S. Department of Agriculture’s Food Loss Project, we throw away more than 25 percent—some 25.9 million tons—of all the food we produce for domestic sale and consumption. A 2004 University of Arizona study pegs the figure at closer to 50 percent, finding that Americans squander some $43 billion annually on wasted food. …

You’d think we could at least make sure it gets composted, before it gets to landfills and generates methane, a potent greenhouse gas 25 times as effective as carbon dioxide in warming earth.