The Oompa-Loompas take issue with chewing gum specifically it makes a woman’s jaw big and strong (that is, more masculine), and it’s also framed as being another type of greed. Miss Bigelow, for instance, couldn’t help but take anything in front of her to chew, to the point that she chewed her own tongue in half. This, the novel suggests, was part of Violet’s problem: she selfishly believed she always needed something to chew, and so ended up in a dangerous situation.