So nice to see a thread already exists, even if the original poster is no longer here (?).
Same situation here: Dieting does NOT work. In fact I learned it's counterproductive during (peri-)menopause because if you restrict your calories too severely, your thyroid and hormones will compensate and lower your metabolism anyway, plus you'll be miserable. So nevermind dieting. 1500 calories per day seems to be my ideal, even though I'm not losing any weight - it's just the minimum amount of calories I need not to bite the world's head off in a rage. Your mileage may vary.
The middlefat comes from a few different things:
1. Your body produces more ESTRONE as your ESTRADIOL goes down. These are two kinds of estrogens. Estrone is made from fat cells and stored there, and your production of it goes up as your estradiol production goes down. Apparently these two kinds of estrogens oppose each other, leading to a vicious cycle. Meaning, as your body makes more estrone and gets fatter, your ovaries think "meh must be time to shut down." Theoretically at least, HRT can stall the process.
2. Your cortisol goes up during perimenopause, part of it due to hormonal changes but also just life itself (stress). High blood sugar can lead to high cortisol. So can lack of sleep or disrupted sleep. One of the telltale signs of high cortisol so called "male pattern" fat distribution - ie your hourglass shape goes away and your belly gets fat. Also, HARD exercise can raise cortisol, which is not helpful. At our age more gentle kinds of exercise (yoga, walking etc) are better.
3. Thyroid issues. Production goes down with age. But more than that, your other hormones affect how your thyroid hormones work or don't work. You can assume that if your hormones are jaggedy your thyroid isn't working right either. This means your metabolism goes way down and you' can't lose weight even with exercise . . . assuming you even have the energy for it.