Dennis Avery of the Hudson Institute, a Washington D.C.-based policy research organization, says it’s a myth that the world can feed more people if we gave up eating meat. Avery wrote a response to a recent column in the Washington Post that suggested it would be more energy-efficient to grow grain to feed people instead of growing grain to feed livestock. In dispelling that flawed logic, Avery pointed out that grass is cattle's biggest feed source, and although humans cannot digest it, grass happens to grow in a lot of places where grain cannot be raised. In other words, you cannot automatically replace what cattle eat with crops suitable for human consumption.
Read Avery's article.