For years I have noticed this when people I knew lost lots of weight. I recently was in a group for obsessive eating recovery and many people had lost 45-150 # and kept it off for years. You could generally see wrinkling, but there is even a bigger issue-abdominal skin(hidden??). My wife mentioned I was looking older after I lost 20# quickly on one weight reduction program(even though I had lost 60# 3 years previously and we were both relieved at improved health!!. A few of the younger folks that lost 45-150# looked pretty good, but they may hide abdominal skin. I know one person that gained the weight back and lost the wrinkles(also a fast weight loss though). I think we need to get more feedback here!!
I also notice on a TV show where they did surgery on a young guy that had lost about 80# I think, and before tightening the skin to fix this they also removed 30# additional fat!! Maybe that was the key...get rid of that specific abdominal fat?? Body sculpting? Who knows. This is a health/mental health delimma though because this extra skin/wrinkles is a serious problem emotionally!!