Jeffrey Moussaieff Masson was interviewed by Salon, and the discussion involved the ethical quandaries related to eating meat and other animal products. Essentially, Masson believes that even humanely-raised livestock do not live a happy life. Masson believes that animals have feelings, and he thinks that the most responsible choice on an ethical, environmental and physiological level is to observe a vegan diet. Masson addresses these issues and more in his book "The Face on Your Plate: The Truth About Food."
Although his approach is somewhat extreme, Masson brings up some great points about the thought processes that people use to justify their omnivorous existence. Whether you agree with Masson or not, he thinks outside the box enough to create an interesting and informed opinion.