The lightest I can remember weighing was 193 pounds. I can remember the number because I was so damned proud that I had lost 15 pounds. I was down to a size 14, I remember because I found some awesome robin's egg blue jeans with totally useless zippers in the pockets (useless in the design sense, they served no purpose at all) and they had a 34" waist. I was 5'4" and hadn't yet had to look for "tall" jeans. I was 12.
The smallest size I can remember wearing in my adult life was when I was 21, I was 5'9" and a size 24. I remember because I was having to get new clothing of some sort almost every weekend because of how quickly I was dropping sizes. I went from a size 32 to the 24 in just a semester or so, probably due to walking on average 5 miles a day 5 days a week with one weekend of all day hikes once a month. My bra size went nuts, from a 50B to a 38DD/36DDD and I was buying every bright color and wild print I could get my hands on because I could. No more plain beige, white, or black bras! I discovered that underwires were actually pretty damned awesome if they fit right. It was the first time that my bust became the fit issue with clothing rather than my belly.
I went from an estimated 360 pounds to 325. I know because I actually joined a gym and stood on a scale. I was bench pressing 197 pounds, curling 45, and resorted to the pneumatic leg press machine because it offered 790 pounds of resistance. I started training with the vague idea of making getting into power lifting competitions. I also developed a hatred for bikes and treadmills that had nothing to do with my aerobic abilities and everything to do with my still being very large and tall. Bikes never had a seat adjustment that made pedaling comfortable (and we will not discuss the comfort of the seats) and treadmills are made remarkably narrow for a device encouraged to be used for weight loss. Stairclimbers are of the devil.
Now, as of today, I am 327 pounds (if the scale is to be believed) and I have no clue what my actual size is. Based on the jeans that I have on hand it's probably a 28/30. I'm a lot less muscular than I was, alas. I can, in stretch knits and empire waisted styles with ample fabric below the bust, wear a size 24/26 shirt. I tend toward 2X tees that show that "yes, I do have boobs, thanks, stop calling me sir" rather than going immediately for the loose 3Xs. I find myself fairly comfortable about my size and body with the exception of my belly. The T&A are looking rather nice lately, in my opinion.
Thankfully, I know, if the trend in weight lost continues, the belly will solve itself. I have always lost weight in a certain pattern, under the bust for a while, from the face and neck, and then back to the underbust and belly, then thighs. I don't know after that because I haven't ever managed to get that far. Hopefully the boobs never get on the list because I've always, always been cheated in that department. A woman hauling around as many pounds as I do should have a RACK, goddammit!