How to test for Bioelecetrical impedance in an body fat analysier
Per the Wikipedia article:


  The impedance of cellular tissue can be modeled as a resistor (representing the extracellular path) in parallel with a resistor and capacitor in series (representing the intracellular path).


Therefore such a network ought to make a reasonable model for your purposes too.

You'll need a way to get some ballpark values for these components; one option would be to use your own impedance analyser on some volunteers to figure out what's reasonable. The literature on this sort of measurement probably has plenty of examples too, however.