"Well, what are you going to do now, my dear? More cookies? Something else?" The old man asks, watching her expectantly...
"I don't know..." Belinda answers, looking at the cookies with a lingering eye. "Those are some VERY good cookies..."
"Have as many as you like, but keep in mind... go too far, and the spells are irreversible. You've already gone too far on the cake, but you haven't gone too far on the cat yet..."
"Irreversible? So I can never be thin again?"
"Not magically, at least. The only way you'll ever lose weight now is the natural way... which would be very difficult at your size."
"Hmm. Well, hell - if I'm gonna be fat forever, I might as well be a fat cat forever, too." And with that, she picks up the tray of cookies and shovels every last one of them into her mouth.
The first thing that happens is that she begins to get smaller - not slimmer, but proportionally smaller. Her thumbs pull back and become dew claws, as do the big toes on her feet. Her ears pull all the way to the top of her head and her lips form into a cat's mouth, no longer able to articulate words. She is now one hundred percent persian cat, albeit a 48-pound cat.
"Meowr," she mewls as she pads over to the old man and rubs up against his legs. She is rather accepting of the role of a cat, it seems.
"Well aren't you a pretty little thing," the old man coos as he bends down to pick her up, and finds that he can't. So he settles on petting her instead.
"Well, young lady, I won't force you to live here with me, be my own little pet kitty, but the option is always open. Just so long as you never sit on my lap. I don't particularly want my legs crushed," he says, smiling. Belinda, despite being a cat, understands him perfectly. Her size is no hindrance to her movements, either - being magically induced, it is not beholden to natural laws of physics. So she's four times the size of a fairly large cat while remaining just as agile.