I recently attended a health seminar and one of the “must-sees” was this 2011 film documentary called Forks over Knives.
It is not only a film but a movement with a strong online presence where you can view recipes, be part of the community and get to know a little more about the research that went into the film.  With all of the you are what you eat philosophies in circulation, this firmly pins the vegan argument to the board:  http://www.forksoverknives.com/