Donald Watson (Sep. 2, 1910 – Nov. 16, 2005) founded the first Vegan Society, inventing the word vegan itself in 1944 using by cutting the central letters of the word "vegetarian". Born in a non-vegetarian family, in an environment where the practice of vegetarianism, or veganism, was unknown. He stopped eating meat after witnessing the slaughter procedure, and vegan after learning about how milk was produced.

"It’s the beginning and end of vegetarian. because veganism starts with vegetarianism and carries it through to its logical conclusion."

 He was able to surprise his many critics who claimed that he could not survive on his proposed diet by proving that he would not only survive but survive well and free from the need for doctors’ interventions in his final days. (Wikipedia)