I swear by psyllium husk capsules from Holland and Barrett. Been taking them since about day 4 of the diet and they've worked a treat. There was one weekend where I was lazy/forgetful and didn't take any and let me tell you, I won't be making that mistake again. Painful doesn't even cover it!
They're usually about £12 a tub for a month's supply but they're currently on offer essentially for buy one get one free.