When my parents were teaching me vegetarianism as a child, they told me that it was just better in a healthy way. I was eating foods that would keep me healthy and depleting me into a bad habit.
I'm not saying meat causes obesity, but that is one of the reasons my parents taught me.
Another factor into vegetarianism/veganism is the basic fact that meat is coming from a dead carcass.
But very well article, even going vegetarian one day of the week can make a difference for the environment.
Factory farming is a very, very cruel practice. If somebody wants to eat meat, I'd rather they buy their meat from a local farm, rather than a large factory farm.
If anybody is interested in vegetarianism and want to see what happens in slaughterhouses, check out http://meat.org/