SARAH: In Shakespeare's time, England was still an agricultural society: food was expensive, and almost everyone did manual labor of some kind or another. Accordingly, it was rare that people became fat —

RALPH: Falstaff, in Henry IV, Part 1, is an exception!

SARAH: As I was saying, it wasn't people that became fat, but animals were certainly fattened up, in preparation for slaughter.

RALPH: But the word fat was sometimes used, as it is used here, to describe the characteristics of animals who were penned up and fattened — they were seen as being dumb, slow-witted, or lazy.

SARAH: So these weeds aren't particularly obese — it's as if they've become slow-witted from growing on the banks of the Lethe river, which causes forgetfulness.