I was just idley surfing the web as I sometimes do whrn I should be doing work, and I came across a link to an article about why being a vegitarian is unhealthy and unwise. It goes about examining the most common reasons people cite for being vegitarian and tears them down one by one. I thought I'd post it since I know some vegitarians and I've always felt the same way as these people do, that it's a logically unsupportable practice that's done primarily because the person in question is ill informed or wants the feelings of specialness or control over their life that it provides.
http://www.lloydianaspects.co.uk/opinion/veggie.html You might find it a bit source-shy. It's essentially written as one man's opinions, but that's O.K. It's O.K. because everything it says is backed up here:
http://www.becomehealthynow.com/article/dietbad/293/ And that one is fully sourced.