Weight class based sports are a different beast and sometimes what we do is not necessarily healthy when it comes to making weight. If you are looking to maintain strength, conditioning and overall wellness it is important to research and understand how hydration and dehydration effect the body.
Most here will not experience the unhealthy sides of cutting weight but it is still important to understand how to do it right. Hydration is important but weight class athletes will dehydrate themselves very quickly just for a weigh in. I remain fully hydrated until 24 hours before weigh in but I can offer some experience in how to cut weight the right way long term. Remaining fully hydrated actually will help you in your cut because as most know when you are fully hydrated your body will NOT retain water and flushes all excess water. Maximum hydration is the key to a successful cut. If you are drinking less than 1.5 gallons a day you are not drinking enough. If you are not sweating you are not hydrating!
Read up on the hormone vasopressin.