Absolutely agree about heavy breathing and stamina, they're goated.
I don't care for size of the girl that much, as long as she gets out of breath quickly.
I like small aspects, like when girl is trying to avoid stairs and getting up, when she's sleeps a lot more, when she starts to be out of breath when talking, when she when she's tired most of the time and when she's overheating constantly.
Those minor aspects that even she herself isn't paying attention anymore.
Also parts of body like ankles, hands, feet and face are goated too.
When girl is so fat, that even her hands and feet get fatter, it's insanely hot