6 mos diet and exercise

im once again contemplating wls. im going with the rny just because id rather have lapband but due to my camc insurance it would pay for the surgery but not for the adjustments of the band. my insurance requires a 6 mo diet and exercise plan. i was on ww for 2 mos and didnt lose 1 pound. then after that my diabetes dr chg my diet plan and now on that i havent lost any either. im wondering what diets have people been on to lose the weight on the 6 mo diet. any suggestions will be appreciated. i do work night shift so i dont have the typical normalized work schedule