Hi chubz85, every surgeon is different in their requests regarding do opti before surgery,so do and some don't.it depends on actually how overweight you are and how high your bmi is.the idea of going on option is to shrink your fatty large liver down which in turn gives the surgeon more room when doing the procedure and is easier to see what he is doing.your surgeon is the one to call the shots by how large you are and if you are very fatty in the stomach area too. I did not have to do opti but did it for three days before just to clean the stomach out a bit,it was my own choice.Just check with your surgeon what he requires you to do.it makes for a safer operating procedure to have the liver shrunk down in size.