I don't know what the middle of middle age is (50?) but I identify. I was really starting to spread when I reached 50. I started biking to work (14 miles round trip) and it worked for me for a while. My then nacent gut vanished and I went around telling everyone they should bike to work.
It didn't last. My 60s happened. I kept biking to work but no more bikini body.
Now I'm 74 and I genuinely look like shit warmed over shit. I bike around town but my gut sticks out like I swallowed a watermelon an I have a ridiculous outie. My moobs can fill out an empire waisted dress. I have no waist at all. I have to take care not to show buttcrack.
Yet one of my besties is as trim as ever, and he does nothing to maintain it. I'm convinced we all have the bodies we have and are going to have, pretty much locked in. But all that exercise helps. I'm in my 70s and although I may look like shit, I feel pretty good. So keep at it.
You know what does work? Ozempic. My wife gets paid to take it as part of a study. The pounds are sliding from her like snow from the roof of a heated house.
They lied. Drugs are the answer to all of our problems.