Have a good meal of whatever is desired to help replenish yourself
Carbohydrates need to be low in quantity, regular and of low glycaemic index choices during the daytime, things like basmati rice, sweet potatoes and porridge. Following the weigh-in, carbs are a mixture of high and low GI sources. The high GI ones are to get the depleted stores back up as quickly as possible before the fight, whilst the low GI choices (oatcakes) are to prevent you running out of energy in the ring.
Before the fight you will be partially dehydrated, so it's imperative that you rehydrate as a lack of fluid will limit your boxing performance much more than any other nutrition inadequacy will. Commercial isotonic sports drinks can be useful here, as well as sipping water frequently before the fight (sipping rather than guloping is important to avoid bloating). Lightly splashing water on the brow before the fight is a useful hydrating tip as this will help keep you cool and reduce sweating, causing even more water loss. It will also help reduce the risk of sweat running down into your eyes.
As with all boxing meal plans, this one was merely a guide and shouldn't be stuck to rigidly. You must eat a variety of different meats/fish /alternatives, complex carbohydrates, fruit and vegetables every day, and drink plenty of water. Adapt the meal plan to suit your own needs, according to your personal results.