I can speak from experience about this. I had lap band surgery over 3 years ago and had many complications with it. I had it removed in October of 2013. Originally my doctor was going to do the sleeve at the same time, but there was too much fat around my liver to do it safely.
My doctor put me on the pre op diet and told me I had to lose 50 pounds before he would do the sleeve surgery. I lost 16 pounds the first week on it, but the longer you are on it the slower you lose it because your body goes into starvation mode. It took me a little over 8 weeks to lose the 50 pounds, but it was worth it. In total I was on nothing but liquid for almost 11 weeks. It is not something that I would recommend as it is very emotionally draining. I had my sleeve surgery on December 10 and as of December 23 I was down 28 more pounds.