Back in the early 80's I cut twenty pounds from 146 to 126. I was a shell of myself at 126 but only had to make weight once before I got the 5 lbs after Christmas.
(It is ironic as I write this my freshman son is cutting weight for the duel on Thursday is searching our pantry knowing he can not eat.)

I am glad that I know what he is going through and I would never allow him to do the stupid things I did to make weight. Going three days without food or two days without water.

I can't honestly tell you how it affected me on the mat. I never thought it did, because I always that I was the strongest and meanest 26 pounder alive. I was not but I sure thought it!
In hindsite I should have realized that the severe lactic acid build-up and cramping after each match was not only a result of my dehydration but my lack of proper diet.

Good luck and please cut weight the right way!
The lower weight class you are trying for is not always as easy as it appears!