My useful items are prunes -- eat the with Greek yogurt for a lovely dessert or if I need something stronger Milpar. It's a very gentle laxative. Don't know how they fit in with your particular regime.
Your digestion is probably a bit messed up with fasting! apparently the scan bran gets you going, pity it tastes like cardboard even with dairylea extra light on it, anyway, thats what I tried today as am normally regular but not been great since starting SW!
The best way I know is abdominal massage, press quite firmly up the right hand side of your abdo across the top and then down the left hand side of your abdo, keep going round your abdomen in a circular movement (this follows the natural direction of the bowel movement) always works for me!!! Plus drink plenty of water too