RE: This is reversible by losing fat weight.
Tell it to my thyroid. (low thyroid with levothroxine taken daily).
Also each decade older the same weight loss targets become more elusive.
I watched the last hour or so of The Truth About Fat on PBS.
It interviewed the Biggest Loser victorious subjects——all after they had regained all the fat plus more about 3 years later.
Scary show. The body keeps plotting to discover what you are doing and undermine you to keep you fat so you won’t die in the caves again as in the earlier ice age days. Cave people with weight gain genes survived to have children to pass the bad news onto all of us. “Set point” adjusts so more exercise and less eating result in more new fat pounds added.
That's their stories and they are sticking to it.