Nimmo was a vegetarian but became vegan in 1931 after witnessing a cow and its calf on opposite sides of a road, separated by fencing."Throwback Thursday: Dr. Catherine Nimmo, Vegan Pioneer". American Vegan Society. Retrieved 6 October 2021. In 1948, Nimmo and Rubin Abramowitz formed the first vegan organization in the United States known as the U.S. Vegan Society in Oceano, California.Iacobbo, Karen; Iacobbo, Michael. (2004). Vegetarian America: A History. Praeger Publishing. p. 167. Stepaniak, Joanne. (2000). The Vegan Sourcebook. McGraw-Hill Education. pp. 6-7. The Society lasted from 1948 to 1960 and was a predecessor to the American Vegan Society.Inness, Sherrie A. (2005). Secret Ingredients: Race, Gender, and Class at the Dinner Table. Palgrave Macmillan. p. 156. Nimmo distributed copies of the UK's The Vegan Society magazine and corresponded with Freya Dinshah and H. Jay Dinshah. She joined the American Vegan Society and was its first paid member. She authored articles for the American Vegan Society magazine, which at that time was called Ahimsa.
