The way I see it, there are two ways to think about the ethics of meat eating. One is to look at the suffering of each individual animal that is killed for consumption. The other way is to take a global approach, where one is concerned with negative environmental/human consequences caused by the meat industry. Of course, you don't have to choose one over the other, it just seems worthwhile to make a distinction. With this distinction in mind I'd like to call attention to a recent piece by George Monbiot in The Guardian that argues that much of the human malnutrition connected to the meat industry could be alleviated most effectively by changing the system in which animals are farmed. The author, a longtime proponent of veganism, had some of his assumptions challenged by the book Meat: A Benign Extravagance by Simon Fairlie.
From "I was wrong about veganism.