。
It seems she's getting fatter and fatter.
Literal
She [topic-は] increasingly fattening goes [seems-ようだ].
Three layers of grammar pile up here: 太る ('to get fat'), the auxiliary ~ていく (a process unfolding away from the present), and the evidential ~ようだ ('seems, appears'). ~ていく specifically points to a change continuing into the future, while its sibling ~てくる would point at a change that has been happening up to now. ようだ marks the speaker's claim as inferential — based on what they're seeing, not on direct knowledge.