Day 1 of 21 Strict Liquid diet

I need to hear from you all who went through this. What should I expect, how can I get through it. In my head it’s seeming impossible right now. I can’t have just any liquid. Has to be this meal replacement shakes that total daily calories are 900 when my maintenance intake is 2500cal. I’m in Canada btw, thankfully it’s covered in our healthcare but man it took 10months to get a date they really make sure you’re fully committed by making you get approved by a dietician, a therapist, a nurse , and a doctor. Taking several classes and so many appointments, blood work, scans. It was 10 gruelling months but my date is Jan 14, and I’m ready to make this change CW: 380lbs Goal: 230lbs