I didn't have to do diet before my surgery. One week post op, I lost 14lb being on the liquid diet. But as soon as I started the soft food diet I gained 3 lbs. I'm now 3 weeks post op n have lost a total of 21 lbs. But I know as soon as I start solid food, I'll probably gain a few lbs back is like regular diets.But hopefully without the hunger I can't wait for my first fill in a few weeks. Remember to walk every day I've notice that if I don't walk my wait stays the same I have to keep motivating my self. hopefully my experience helps you. We all need a good support sistim to help us thru our journey. Every time I come to here motivates me