Food waste has gotten a lot of attention lately, and rightly so. In the United States, we trash up to 40 percent of our post-harvest food supply. But there’s another, more insidious form of waste that plagues our food system—and it’s baked right in.

We devote more than 100 million acres of U.S. land to growing crops that don’t contribute efficiently to our food system and in some cases pose an outright threat to our health and the environment. Federal agriculture policies have a powerful impact on decisions made at the farm level. We need government policies that support the use of farmland for nutritious food—as well as conservation and climate protection—not for wasteful products.

Revising how the federal Farm Bill program subsidizes or otherwise supports certain crops and practices, for instance, could change which crops farmers choose to grow and how they grow them, reducing waste of all sorts.

Conventional beef is a prime example of the inefficiencies in our current food production system. According to the U.S. Department of Agriculture (USDA), about half of U.S. cropland is used to grow feed for animals in industrial livestock facilities, better known as factory farms. In the 12 states of the Midwestern “Corn Belt,” 70 percent of planted acres are devoted to just corn or soy. But the average American cornfield feeds only three people per acre, making it less productive than farms in Bangladesh.

That’s because feeding grain to animals and animals to humans is a highly inefficient way to feed people. According to industry sources, most feedlots require about six pounds of grain to increase a cow’s weight by one pound. Then, less than half of the cow becomes edible meat. In the end, it takes more than 14 pounds of grain to produce one pound of beef sold in a grocery store.

That’s about as efficient as filling the gas tank of a mega-SUV that only gets two or three miles to the gallon, compared to a car getting 30 mpg. If you fed the same amount of grain given to…