@dawei7 So, I can totally identify. I had a bodpod scan done last year and found out I had a nearly-normal BMI and 40% body fat. I was, at the time, 30f, 152 lbs, 5'5". My RMR came out to be around 1100 calories.
Sarcopenic obesity was new to me, but I'm glad to now have a name for this term. So, thanks for that.
Anyway, I decided to cut for a while--which wasn't all my decision, but my endocrinologist told me that she wanted me at a BMI of 21. That means getting down to 125 lbs, so off I went. It took some trial and error to find the right cutting calories mixed with more resistance training to hopefully build/maintain what little muscle I could. I took a maintenance break during the holidays as well.
Anyway, I decided to cut to at least that and get another scan to see what my body fat percent was. I have read some stuff that says you should get to 20% body fat before bulking, but
this calculator seems to think I'd need to get down to like 112 pounds to do that (if the body fat percent on my Aria scale is accurate... which it was close to my bodpod scan, so I'm going with it as pretty close). I'm not sure I can cut that long, to be honest--that would just be too much to handle, psychologically.
I might also cut down to maaaaybe 120 pounds or until the end of summer, whichever comes first (who wants to be gaining over the summer??? If I hit 120 before then, I'll maintain) and then bulk starting in the fall.
Regardless of what you decide to do, I think that you should calculate your TDEE and go off of that--not your RMR. Add resistance training/weight lifting ASAP to build/maintain muscle. You won't likely build much on a cut, but you also can't afford to lose what little you have.
When I was on my maintenance break during the holidays, I did see my body fat percent go down on my Aria scale even though my weight stayed the same--so you could also consider a recomp, where you eat at maintenance or just a little above that and lift to build muscle. This will make you smaller without changing the scale much, so if you're willing to give up on the scale for a little bit and be ok with slowly losing inches, this could be a good route for you.