My cat is gettin skinney?

I would just for a check up, is she getting REALLY skinny, or just looks like she is losing a bit? Have you recently changed foods, is she getting more exercise? I got my cats a cat tree, and every since then they have both slimmed down because they exercise all the time on it. If its in any way a drastic change, a vet visit would put your mind at ease. Good luck!!