I'll need to redo some reading but I was under the impression that the TG (Triglyceride) which make up 90% of the Adipocyte require a gram of water for each gram of TG. I see some things that indicate the same thing online but it is less clear.
As an interesting sidenote: fat people have relatively a lot less water in their fat tissue than lean people.
You can also think about the fact that when you drop triglycerides in water, it will not solute at all. Also, human body creates fatty membranes (cell walls) to absolutely _prevent_ the influx / efflux of water.