This is last years version of his standard on-the-road lecture with 
much supporting info.  This will probably become my new go-to page 
for vegetarians and vegans.

I always tell them that, as an ex-vegetarian, I respect and 
understand that their religious dictates, or ethical position on not 
killing animals, is the source of the strength that keeps them true 
to their dietary choices, in the face of irrefutable scientific 
evidence that their path will lead to short and long term damage to 
their health.

This, of course, has no impact on the zealots.

Then there are those who, due to succumbing to effects of propaganda, 
rumor, peer pressure, or whatever, have been mistakenly led to 
believe that they were on a path the greater heath... if smart and/or 
curious, they take note and ask for more information.  Those few 
really make my day.

Loren Cordain - Origins and Evolution of the Western Diet: Health 
Implications for the 21st Century.

http://www.youtube.com/watch?v=5dw1MuD9EP4