How much have you lost? Your legs used to have more padding between the outside and the nerves, and now that it is gone, the nerves are more likely to be pinched when crossed.

You are likely pinching a nerve. Crossing your legs also impedes proper circulation and is not a good idea! (Pregnant women are advised not to cross their legs as it can cause problems for mom and baby!)

Yeah, man. Stop sitting with you're legs crossed- it's uncomfortable for everyone!

...Congrats on your weight loss.

Get it checked out. What most people call "cutting off circulation" is actually a nervous system issue -- but that could mean neurological as well.

This sounds like it describes it: http://www.drlamb.com/paresthesia.htm as does this: http://en.wikipedia.org/wiki/Peripheral_neuropathy