I've not had an experience with pred (thank goodness) but my cousin was on it a few years ago and for a fairly long time too as I recall. She has Lupus, arthritis and some pretty severe allergies.
I do remember that she managed to lose 25 lbs. while on it I think it took her about 6 months, just eating right and trying to walk as much as possible. She can't do cardio or workout or any exercise like that, so she would get off the bus 2 stops early, things like that. She also got a pedometer and tried to get as close as she could to the recommended 10,000 steps a day.
Hope this helps, and good luck to you!
Height: 5' 0"
Starting weight: 170
Goal Weight: 115
Mini goal: 159 by August 31
Eat five different coloured vegetables every day!