Who Does the Weighing

None of us were weighed at orientation. The doctor weighed me at my meet the surgeon appt a few weeks ago and I was a dead on 40. I'm just concerned that when I see the NUT and RN next week and one of them weighs me, if I'm less weight can I then be refused? That would seem very unfair considering I'm trying to follow some of the things they told us at orientation like weighing and measuring food so now I'm eating less.  I'm probably just being paranoid but this surgery means the world to me.