I think just cutting back to a 1000 calorie diet sounds harder than the 2 week liquid pre op I was made to do (I'm kinda all or nothing). Your diet seems like it would need a lot of will power while limiting real food intake. What kept me on point pre op was the fear of doing anything to mess up my surgery from happening. Do your best, wish I had some tips for you, but I would be struggling just like you. Just know that after surgery you'll be lucky to take in 600 cal a day, that includes protein shakes. Something to look forward to. Stay strong, you can do this.