According to my gal pal, who is an LPN.
A loss of water weight is actually your fat cells being depleted of the water that they rely on. Once those babies are drained, they can start melting away.
Guess you would have to be careful to drink lots of fluid, so the good cells aren't negatively impacted.Many people talk of their tummies melting away overnight. This is why it's happening, I think. They are no longer full of water.
Not sure if that is the best way to say it, but it helped me understand.

