。
She got up from the table without eating much.
Literal
[topic-は] properly without-eating seat [object-を] stood-up.
席を立つ ('to leave one's seat, get up from the table') is a set phrase — literally 'stand the seat (up).' It's the standard Japanese way to describe leaving a seated position, especially excusing oneself from a meal or meeting. ろくに食べないで is the modern equivalent of ろくに食べず: 'without eating much.' ろくに ('properly, sufficiently') always pairs with negation to mean 'barely, hardly.'