She probably lost weight. I mean technically after a WLS it couldn't be the same I think. To me it's not that obvious but I am not always very good at it.
At my first adult job, there was a party for someone who left the company. And there was a pregnant colleague (from another department) who came back from her leave just for this occasion. And I ask how is she and when is the baby due (looking at her belly)... Turns out she already had her baby weeks ago. Still thinking about this and I am still mortified