[E]ating meat is an extremely inefficient way of turning vegetation into food. If everyone gave up meat—or even just ate pork instead of beef—we’d have a big grain glut. The issue, of course, is that people don’t want to give up meat. On the contrary, as the world gets richer people are shifting toward incorporating more meat into their diets. That, in turn, creates a kind of food chain gentrification problem for those individuals who aren’t, personally, getting richer since it pushes up the price of grain.
(Matt Yglesias.) Which reminds me: when we colonize the rest of the known universe, will it tend to consist of desolate central planets surrounded by affluent satellites?