Im too cheap to go out and buy a plastic outfit. I personally had to weigh less than 158 on Sat. I was running about 165 - 168 range depending on the tiem of day. Starting on monday All I ate was raw vegetables and meat. No grains no fruit no sugars, and no soda (that was hte hardest for me.) I spupplemented my diet with a multi vitamins and my normal glucosim chondroiten stuff.
After the gym thrusday all I drank was the water I needed to down my vitamins. Friday at work I wore a lead vest all day (normally to protect people at the hospital form Xrays.) after work i went to the gym with a big plasitc bag full of sweats and rash guards. I wore rash guard, t shirt plastic bag and then a sweat shirt. I did 3 sets of bicycle stretch in the sauna routines. of 20 mins each. and showered afterwords. Between each routine I changed clothes and re weighed my self. I also chewed sugar free gum and spit in a cup. In less than a 2 hour period I was own to 156. (so 163 - 156 in 2 hours.) and that included a shower.
The biggest key I think is what my old BJJ teacher always said. The week of the fight never do anything new or different. I normally sweat in a sauna 20 mins each day to stretch before I work out and go to BJJ. I do a little of dehydrating all through out the month so my body is use to it. Fasting is a good way to clean your system out not just before a fight. And stretching is a good way to pass time when you are in the sauna boiling.
The hardest thing I have ever done in MMA was to sweat weight. It hurts more than a shot to the head or a kick to the shin. The people who win MMA fights are the ones who win it by training harder before the fight. Like the guy earlier said .. keep a buddy with you, if you have negative self talk lke I do you realy need someone motivating you to keep your ass in the sauna so you dont go stir crazy.
good luck.