Not fat, specifically, but portrayals of Suffragettes as being physically unpleasant, rhetorically unsound, excessively violent and foolish weren't uncommon in the early 20th century.

https://www.cartoons.ac.uk/group/were-suffragettes-taken-seriously-teacher

http://cdn.c.photoshelter.com/img-get/I00001J3wesi3xmY/s/900/720/Suffragettes-Votes-For-Women-Cartoons-Punch-Magazine-1906-01-17-39.jpg