Vegans in general eat right, but there are a few that are simply vegan to better the environment and they eat anything as long as it is animal product free.
I would argue you cannot be a true vegan if you don't eat right. It is not wise stewardship of the human body to place foods or drinks into it that are harmful. Why save the whales, while encouraging breast cancer in your own body with a glass of wine? Why protect the trees and air quality, while smoking a joint on occasion, causing over 400 chemicals to pursue through your lungs?
No, I would say you can't be a vegan and drink wine, beer, smoke funny cigarettes, or otherwise harm your body. Your body is part of this plant, and you don't approve of cancer research on monkeys, but you'll do it on yourself.
Whether you believe in God or evolution, the fact remains all creatures should be protected, including your own body.
That's my two bits,