I'd been vegan for 1.5 years for ideological reasons still eating lots of processed junk, lots of coca cola, fried foods and mock meats and mock cheeses and using oil so that I didn't feel I really changed anything except I wasn't part of the animal foods industry when I started HRT fluctuating between 65-70kg, and this is the range I stayed in all my life, even when I still ate meat and dairy. All my life I was used to eating whatever I want and still being skinny. When I started HRT I stayed the same weight but my belly started to bloat. Perhaps I lost muscle mass which was exchanged with belly fat. As I was bothered by this making me look even less hourglass figure than before and my dad's dementia worsened, I became health concious for the first time in my life and moved closer and closer to a whole foods plant based nutrition.
The resulting combination of losing back the fat I gained in the first few months of HRT and losing the muscle mass I had before HRT resulted in me fluctuating these days between 60-62kg. My height is 1.79 meters.
Bottom line - if I had kept eating what I was eating before HRT, I probably would have gained weight.
Another note - throughout all this my body as a whole stayed skinny in all parts except the belly. That was the only place in my body that gained and lost fat from what I could tell.