I’ve been approved for my bypass. Surgery scheduled for 3/5/18. I have decided to start on my pre op protein diet last Sunday so my body doesn’t go into “shock” from no sugar or caffeine. Not really following it exactly as I should until 2/19. Anyways, I’m losing a lot of weight already. Is it possible that my surgeon will cancel my surgery after I’ve already been approved and scheduled if I lose a whole bunch of weight and go under the minimum BMI for my height?

Your surgeon will take your starting weight as the basis for surgery and they expect you to lose weight prior to, in order to show your commitment to the lifestyle change that is needed post op. Lose all you can now, and stay on your pre op diet.