But we need look no further than our own shores to figure out what’s causing food crises overseas: While millions of people are starving, a billion more—many of them Americans—are overweight. Our addiction to meat is largely to blame for both problems.

When world leaders met at the United Nations’ Food and Agriculture Organization summit in Rome earlier this month, they vowed to halve global hunger by 2015 and discussed strategies to boost agricultural production, which must be doubled by 2030 to meet rising demands. But no one proposed a convincing way to alleviate world hunger.

Dr. Walt Willett, professor of medicine at Harvard University and author of Eat, Drink and Weigh Less, offers this simple solution: “If we changed the way we ate, modifying what we eat, we could practically end the global food crisis, since eating more crops and much less red meat … would free up resources to feed the world.”

It would take just 40 million tons of food to eliminate the most extreme cases of world hunger. Yet a staggering 760 million tons of grain will be used to feed farmed animals this year (compared to 100 million tons used to produce fuel). Around 1.4 billion people could be fed with the grain and soybeans fed to U.S. cattle alone.

In the midst of a global food shortage, it is wasteful to feed perfectly edible food to farmed animals rather than feed it directly to malnourished people—especially when you consider that it takes 4.5 pounds of grain to make a pound of chicken meat and 7.3 pounds of grain to produce a pound of pork. Even fish on fish farms must be fed 5 pounds of wild-caught fish to produce 1 pound of farmed-fish flesh. This is inefficiency at its worst.

It’s not a new problem either. In 1947, President Truman asked Americans to stop eating beef on Tuesdays and chicken and eggs on Thursdays to help stockpile grain for starving people in Europe. According to the Worldwatch Institute, the number of farmed animals has increased 60 percent since 1961, and the number of birds being raised for food has nearly quadrupled in the same time period.

Says Worldwatch, “[M]eat consumption is an inefficient use of grain—the grain is used more efficiently when consumed by humans. Continued growth in meat output is dependent on feeding grain to animals, creating competition for grain between affluent meat-eaters and the world’s poor.” Simply put, we could produce more food for more people if we stopped squandering our resources to raise animals.

It takes 3 1/4 acres of land to produce food for a meat-eater; food for a vegan—someone who eats no animal products, including dairy and eggs—can be produced on just 1/6 acre of land. Vegfam, a U.K.-based charity that funds sustainable plant-food projects, estimates that a 10-acre farm can support 60 people by growing soy, 24 people by growing wheat or 10 people by growing corn—but only two by raising cattle. While some are blaming developing nations like China and India for creating food shortages, Americans should look in the mirror before pointing fingers. According to The New York Times, Americans eat twice as much meat as the average person worldwide.

Parents have long cajoled American children to finish their fish sticks or pork chops because “people are starving in China.” Now we need to encourage people of all nationalities to eat their veggies—as well as beans, grains and fruit—instead of animal flesh if we are to alleviate hunger. As George Monbiot of The Guardian wrote, “[I]t now seems plain that [a vegan diet] is the only ethical response to what is arguably the world’s most urgent social justice issue.”