I'm dropping a lot of weight for wrestling this year and I don't know if I can stay that light all the time.
Is there any way to drop weight just for the weigh-ins (which are on the day of the match) but not feel tired for match?
For same day weigh ins, cutting a lot of weight is not ideal, and it will affect your performance.
That being said, if you are weighing in early in the morning, and competing later in the afternoon, you will have some time to properly rehydrate and recover.
This question talks about some techniques that are out there: Dropping weight before a MMA fight
But it mostly applies to the day before weigh ins that MMA has.
For wresting, BJJ and Judo, I would really recommend getting leaner, and not cutting, and if you are cutting, not being more the 5lbs over a week before the competition.
5 lbs you can get rid of with a strict diet, lots of fiber, and a little bit of dehydration.
Generally for weight cutting, you need to keep your protein up, and avoid almost all carbs and sugar (and by carbs i mean grains, and super starchy vegetables, things like spinach, brocolli, and such are fine).
Drink tonnes of water the week leading up to the fight, and then the day before only drink when you are quite thirsty. This process is pretty common, and will super hydrate you, so your body will think it is going to keep getting all this water, so it just sends it straight through and keeps doing that, even when you only drink a little bit the day before. This has varying degrees of effectiveness, depending on your body, your diet, and whatnot.
Also, really restrict your sodium for about 2 days before weigh-ins. Sodium can really mess up a weight cut by making you retain water.
After you weigh in: Gatorade / Powerade aren't bad for re-hydrating, but a bottle of Pedialyte (In the baby isle of your local drug store) is better. Pedialyte is designed for babies who are sick and dehydrated from it. It's great stuff. (The no name brands are pretty much the same, so if your on a budget you can have that to).
Also, Don't Guzzle water like crazy right away, take your time to rehydrate or it'll go right through you.
If you have had to really restrict your food to make weight, make sure you have some fruit to eat to. It'll give you some sugar to use for energy right away.
That about sums it up!
You don't give much info about your weight or age. That would help me give you a better plan.
At 28 years old, I would cut 5lbs an hour, for a total of 2 hours to make weight for freestyle tournies. By making the ambient temp in the room as warm as possible. I would then put on a cotton layer, then plastics, then a couple of layers of sweats. I would then exercise at a high pace for 5 minutes, play computer games for 10, workout for 5 and rest for 10 for the two hours. Go to weigh in an hour early and check weight. Cut more if needed. Remember your goal is sweating to make weight not working out. This was my no muss no fuss way.
In school you have a lot of crap going on around you that can get in your way. If you are in school wrestling you will make weight around an hour before your match. To modify the cut I would eat and drink normal to 24 hours before the scales. Then no more solid food, in the morning drink a protein/energy shake and if you can handle it coffee and a lot of it till 7 or eight hours before the scales. You will need to find out what conditions allow you to cut x/pounds an hour. Start your cut at lunch, try for 20% of the cut. After school try for 50% of what is left and then finish 10–15 minutes before the ref arrives or you arrive at the other school. This will be the hard part if you are traveling. As for drinking after weigh in, I tell everyone that doesn't need to make weight again that night or the next morning," drink a mouth full untill you piss clear/white. Don't gulp or guzzle more than is strictly needed because it will just come up during your match.
Last bit of advice is to know yourself. When you know that you can, map out a weight cut and it is super easy. Write down your thoughts and feelings during the cut, review them after and make changes as you see fit.
If you are going for a tournament you should follow a program to everything, your training, your diet, your rest everything. So you should follow a program to lose weight and stay fit with endurance. There is no magical way to do this. Have a schedule and just follow it. Close to your tournament days you should rest, make a plan of your gameplay and watch your diet. Good luck.