50 Is the New Crappy
As for the rest of me from the neck down:
I've veered from a size 0 to a 14 twice in adulthood; one round was health related (see "lupus," above), the other was after I quit smoking and met my future husband, who has a raging sweet tooth.
Right now, I'm a size 4, and have finally accepted, after a ten-year mourning period, that I will never be a 0 (with a 20 inch waist) again.
In fact, this year I discovered that my "ideal weight" wasn't quite what I always thought it should be.
The old fashioned actuarial rule used to be that a 5-foot-nothing female should weigh 100 pounds. During my teens through my 20s I did, which meant I could still shop in the children's department. (No sales tax!)
But it turns out I wasn't taking something called "frame size" into account. Your crazy loud aunt was right: "Big boned" is an actual thing.
While I was briefly mortified to learn that, according to this formula, I had a "large" frame, it was also enlightening and reassuring to be told that I'm actually supposed to weigh between 116 and 127 pounds.
Plus I don't let myself listen to Adam Carolla's podcast unless I'm on the treadmill, so that gets me down to the condo's fitness room every day.