I've gone down from an 11 (mens)/12 (womens) down to 10 womens. If you retain fluid you will lose weight in your feet area. It was funny, as I didn't notice the difference until I went to try a new pair of shoes on, and the right one fell off my foot as I tried it on.

I went home afterwards and tried on some shoes I haven't worn since summer started, and lo and behold, they are bigger on me.
So, I went from a 12 to a 10 in about 7 or so weeks time, but that's fluid loss, which is great. I haven't had "hot feet" in a while- at night, my feet used to be so hot in bed, I'd get up some nights a take a cool clothe to cool them down.
Before I got this heavy, I was a size 9/9 1/2 womens.