They say that the skin is very elastic, and it will get tighter with time...A lot of time it is loose if you lose too fast. Toning, doing something like yoga may help.

My personal experience was that my skin did not tighten(last time I lost). I did end up having plastic surgery...and will again once I get this weight off again. ( to get rid of the stretch marks more than to tighten loose skin, but it is nice to have a beautiful flat tummy and not have to really work at it!) I like the results...but that is just my humble opinion.