I've heard of losing an inch or two, simply because you gain weight on your head and feet, and when you lose you also lose weight in those places, hence losing some height.
I don't remember where I found it, but there was a study on this a few years back. Ultimately, if you lose a large amount of weight, say 50 pounds or more, you tend to "grow" by half an inch to a full inch. After all their sciencing, the real answer was the bones didn't grow but people stopped slouching as they were not weighed down as much and walked taller due to confidence. I'll try to dig up the article, it was a cool read.
I'm an inch taller than I was 100 pounds ago - the weight caused my frame to spread a bit and put a lot of pressure on my spine and the bones in my feet. When the load lightened, the 'springs' of my physiology relaxed back out a bit from their compression, too.
I gained an inch which I attribute to yoga. I was 5"8" forever, then a few years ago (after my yoga practice became much more regular) the drs started measuring me at 5'9".
I have never been entirely sure of my height, just that it's between 5'4" and 5'5". The last few times I've been to the doctor I've been well over 5'5" ... so much so that I made them redo the measurement.
It was bugging me but I never realized it might be related to the weight loss ... the thing is, I don't think I was this tall even back when I was skinny.
But the one thing I know is that in my family I am the shortest by quite a bit. All the weight loss in the world won't change that ....