hi, well I'm on day one of a Water Fast
right now and i'm on day 3 of my period. I have fasted over my period a few times before - the answer to whether or not you will still lose weight is 'yes' and 'no' and 'maybe' - lol sorry for the confusion. Okay because there is two typical types of weight loss, the loss of water, and the loss of mass (fat and/or muscle) its true that fasting over your period can give less 'impressive' results, as your body at this time of the month tends to be retaining water anyway, i've found the water weight loss during menstruation to be quite low. Fat/mass loss is not affected though - and this is the real type of weight-loss which counts. Water weight goes straight back on the minute you start eating anyway. The 'maybe' part of the answer comes from the fact that not every persons body responds the same - some girls suffer from water retention significantly less than others to begin with anyway.
So, whether or not you want to embark on a fast while you are having your period i guess depends on your motivation. If your motivation is quick lbs loss then you might want to wait untill your period is over, however if you are only fasting for this reason then you might want to re-consider whether fatsing is right for your purposes, as its a very hard physical and mental journey and i've found when done for vanities sake only can lead one to a pretty dark place.