There is more than enough food in the world to feed the entire human population. So why are more than 840 million people still going hungry?

Our meat-based diet is partly to blame, as land, water, and other resources that could be used to grow food for human beings are being used to grow crops for farmed animals instead. According to a recent report by Compassion in World Farming, "crops that could be used to feed the hungry are instead being used to fatten animals raised for food." It takes up to 16 pounds of grain to produce just 1 pound of edible animal flesh.

The average adult human burns about 2,000 calories per day, just living his or her life. We use almost all the calories that we consume to move around, breathe, and do everyday tasks. The same is true of farmed animals. For every pound of food that they are fed, only a fraction of the calories are returned in the form of edible flesh. The rest of those calories are burned away raising the animal to slaughter weight or contributing to feathers, blood, and other parts of the animal that are not eaten by humans. This is why animals raised for food have to eat as many as 16 pounds of grain to create just 1 pound of edible flesh.

Because the industrial world is exporting grain to developing countries and importing the meat that is produced with it, farmers who are trying to feed themselves are being driven off their land. Their efficient, plant-based agricultural model is being replaced with intensive livestock rearing, which also pollutes the air and water and renders the once-fertile land dead and barren.

If this trend continues, the developing world will never be able to produce enough food to feed itself, and global hunger will continue to plague hundreds of millions of people around the globe. The Guardian explains that there's only one solution: "It now seems plain that [a vegan diet] is the only ethical response to what is arguably the world's most urgent social justice issue."

The more meat we eat, the fewer people we can feed. If everyone on Earth received 25 percent of his or her calories from animal products, only 3.2 billion people could be nourished. Dropping that figure to 15 percent would mean that 4.2 billion people could be fed. If everyone went vegan, there would be more than enough food to nourish the world's entire population—more than 6.3 billion people. The WorldWatch Institute sums this up perfectly, saying, "Meat 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."

Producing the grain that is used to feed farmed animals requires vast amounts of water. It takes about 300 gallons of water per day to produce food for a vegan, and more than 4,000 gallons of water per day to produce food for a meat-eater. You save more water by not eating a pound of beef than you do by not showering for an entire year.

It should be no surprise, then, that food for a vegan can be produced on only 1/6 of an acre of land, while it takes 3 1/4 acres of land to produce food for a meat-eater. If we added up all the arable land on the planet and divided it equally, every human would get 2/3 of an acre—more than enough to sustain a vegetarian diet, but not nearly enough to sustain a meat-eater.

Dr. Waldo Bello, executive director of the Institute for Food and Development Policy, concurs that raising animals for meat is a waste of resources, stating, "The American fast-food diet and the meat-eating habits of the wealthy around the world support a world food system that diverts food resources from the hungry." Researchers and policymakers who study the problem of world hunger agree that we have plenty of resources to feed vegans, but not nearly enough to feed our addiction to meat.