No free feed; get a measuring cup, read the amounts on the bag, and follow them to the letter.
Putting a round cat toy in the dry food can slow down how fast she eats. Also - watch the wet food, if you use it. Very high in calories.
Grain-free food might be an idea, as there is less "filler" and kitty will feel full on less.
Best of luck and I hope your girl feels better soon!
"Common sense and a sense of humor are the same thing, moving at different speeds. A sense of humor is just common sense, dancing." -- William James