Oh this is a good question. I've read that women don't need to IF for so long to get the benefits, i.e. that 14 hours is enough. So perhaps you should cut down to that to minimise this risk.
I imagine it would help drinking a quality mineral water while you fast.
F 5 ft 3. HW: 196 lbs. Primal SW (May 2011): 182 lbs (42% BF)... W June '12: 160 lbs (29% BF) (UK size 12, US size 8). GW: ~24% BF - have ditched the scales til I fit into a pair of UK size 10 bootcut jeans. Currently aligning towards 'The Perfect Health Diet' having swapped some fat for potatoes.