In the 19th century, vegetarianism was linked to a much more radical agenda which incorporated not just health issues but moral, spiritual and political agendas. In the UK the Vegetarian Society was set up in the 1840s and while the movement was always marginal in this period, there was a proliferation of media, books, clubs and restaurants. As always ridicule was never far away as in this cartoon from Punch in 1852. For a very interesting analysis of the cartoon and the movement generally, look at the Happy Cow website (an excellent modern site for anyone interested in vegetarian matters, whether eating or reading) at:
https://www.happycow.net/blog/vegetarian-humour/
If you are interested in the history of vegetarianism more generally, the standard text is Colin Spencer’s Vegetarianism: A History which will take you from Homer and Pythagoras through to the modern day. See: