I brought a boxer in bang on the weight having 450g carbs the day before he boxed. The result? He was actually stronger fighting at a weight he made comfortably. A lot of boxers cut a shit load of weight to 'get the advantage' and it does the opposite. I'm not saying that weight cutting is always detrimental, but it's often not necessary for the average amateurs.
Working with my first MMA fighter atm (just the nutrition side of things), so looking forward to that