I'm genuinely interested in this topic. I'm not saying that vegan diet is the best diet out there, but what I've read so far it really seems to be a much healthier alternative than the "western default".

Some interesting studies about vegan diet and it's impact on health:

http://ajcn.nutrition.org/content/89/5/1627S.full http://onlinelibrary.wiley.com/doi/10.1038/oby.2007.270/full http://www.bmj.com/content/293/6560/1468 http://onlinelibrary.wiley.com/doi/10.1002/1097-0142(1989080...

All these studies contain findings that support the idea of vegan diet being one of the healthiest option: vegans tend to have lower BMI, blood pressure and reduced (prostate) cancer rate.