I'm a former NCAA wrestler who's finished 2 marathons (with the blazing times of 5:01:00 and 5:00:30). All I can say is that anytime you push through a mental barrier, you become that much stronger. Your mental limitations are like muscular limitations - the more you push to the limit, the more powerful you become.
I absolutely believe that there's nothing I cannot do, given the time and energy. I've run 2 marathons at the point of mental fatigue. I've cut as many as 20 lbs in a week for wrestling. I finished a college degree with honors while getting at least a dozen confirmed concussions, who knows how many unconfirmed, and while still competing.
I really feel like I can conquer anything. I actually gave up NCAA to work for free at as many startups I could during my 4th year to do the jobs that no one wanted to do. I definitely feel like a made the right decision. I can't be a pro wrestler these days :)
Don't eat anything besides lettuce and orange juice frozen into popsicles. Run 5 miles every morning wearing 3 layers of sweat suit, possibly carrying a smaller wrestler on your shoulders while you do so. Use chewing tobacco between class so you don't pass out during the day. As soon as you weigh in, eat as much as possible until the match, as both a recovery aid and to actually weigh more than you're supposed to for your weight class, giving a slight advantage over the guy who has to turn you over.
Cutting to make weight is not really a good model for healthy, sustainable weight loss.
TLDR: Mostly lost water weight. I'd done it enough to really know how my body worked. I knew the exercise techniques that worked particularly well for me, and I ate a super-clean diet.
This wasn't a Jared Fogel style "I lost x lbs." He lost fat/tissue. For wrestlers, it's mostly a water cut. In sports like wrestling, boxing, or anything with a weight division you may need to lose water weight to get down to the cap of your division. I was 171 in HS and 197-184 in college. You have to be below the division cap (any over 171 in this case would get you DQ'ed).
Water weight isn't too hard to lose when you start. In your sleep, we all lose from 1-3 lbs, then we use the restroom when we wake up (.3-.6 lbs). If you start with a workout in the morning (1-2 lbs depending on the workout), you can walk 2-3 more lbs off throughout the day. Of course, normal people eat and drink in the course of the day to "refill." Over time, you get to the point where you know how to master this cycle, with extra workouts to boost it, and control your diet to engage the metabolic systems. It's a delicate balance.
In college, I wasn't a starter who had to weight in weekly, so I wasn't always close to weight. Even though we'd work out 2-3 hours a day, we have our bodies to the point where an extra push is required to get down to size. Typically, someone my size and structure should never have been more than 5-10 lbs overweight at most. I just came in one Monday weighing a great deal, and I was also tapped to start for that match to give our starter a rest. Since my resting/homeostasis weight was 5-10 lbs over, losing the first 10 lb chunk was easy. The next portion was a little rougher, but I'd been doing this for 7 years (HS + college), so I knew how to do it.
As for the techniques, I would run, jump rope, and wrestle wearing sweats. Wrestling has a higher caloric exertion rate than boxing, which is already way higher than running or jumping rope alone. Our college facilites also had a steam room, so I would clock time there to keep my sweat up after finishing a workout.
As for diet, I'd start each meal with a couple big glasses of water, so I wasn't quite as hungry and wouldn't binge. I'd then eat nutrient-dense vegetables (spinach salad, bell peppers, seeds, berries). Then eat lean protein (chicken breast, fish, no beef). To end I'd either drink a V8 or a yogurt shake. After all of that water and nutrient dense food, you feel stuffed.
All this being said, you'd have to be completely moronic to try to rapidly that much lose water weight without having done so before. Do. Not. Try. This. At. Home. Trained athletes have died doing this wrong
What's the wrestling opinion on "hyperhydration" (drinking as much water as possible up until two days before weigh-in to manipulate vasopressin and aldosterone levels to essentially mimic diuretics, Tim Ferris wrote about it: http://www.fourhourworkweek.com/blog/2008/01/18/how-to-cut-w...)? That's what's popular in drug-tested powerlifting. I hated cutting weight and the whole "sauna suit" and exercise approach sounds like torture to me, but I've cut up to 15 pounds using hyperhydration and steam rooms without having to do all that much (but I still hated it).
It's the accepted practice now in the collegiate and post-collegiate levels. In high school, people still stick to the old school death by dehydration method, but more experienced people know about the hyperhydration methods.
Actually, some of the best athletes move up weight classes now. Cael Sanderson (only 4x undefeated NCAA champ) comes to mind. It's being determined that moving up and eating well increases your strength and speed, and makes you more successful than cutting too hard (to a point). Everyone these days is incredibly lean and well trained- the difference factor is in stamina now, and it is night and day between someone who cut too much weight and someone slightly smaller, but better nourished, than his opponent.
That's pretty much the opinion I found when I trained with the more elite powerlifters. The top guys only cut when they want to take a national or world record in a lower weight class, and even then they try to lose as much weight as possible by dieting months in advance.
I absolutely believe that there's nothing I cannot do, given the time and energy. I've run 2 marathons at the point of mental fatigue. I've cut as many as 20 lbs in a week for wrestling. I finished a college degree with honors while getting at least a dozen confirmed concussions, who knows how many unconfirmed, and while still competing.
I really feel like I can conquer anything. I actually gave up NCAA to work for free at as many startups I could during my 4th year to do the jobs that no one wanted to do. I definitely feel like a made the right decision. I can't be a pro wrestler these days :)
Edit: Typos -- the head bonks are showing :)