For amber yes but you have to make her gain around 20 lbs. Every time you you go a calorie over the limit that's equal to about 0.045lbs so try to get as much as you can.
I just checked that out.
I had to take her from 150lbs to 200lbs before her model changed.
Is that her final stage or is there more if I keep going?
that will not be her final stage in the future but it's her final stage for this update yes.