We're bound to be hearing a lot more about veganism and vegetarianism now that Oprah and her staff went vegan for a week. Once Oprah talks about, everyone else will follow. 

Oprah isn't the first famous person to think twice about consuming products from animals, of course. Take a look at this video that shows famous vegans and vegetarians through the ages.

I know that Mark Twain's vegetarianism is often disputed. I'm not sure how many other names on this list we can be 100 percent sure of, but it's an interesting list, isn't it?

Robin Shreeves ( @rshreeves ) focuses on food from a family perspective from her home base in New Jersey.