I'm on week 4 of my pre--op diet, just having optifast shakes and 1 optifast bar a day, not doing to bad I am down 15 lbs. last Thursday at my check in. Only 3 weeks till my surgery, hoping to be down another 10 to 15 by then. I drink lots of water in between my shakes to help stop the hunger seems to work for me. Good luck and best wishes to us all!