Similar we were putting together a kids club grade school dual team for a sort of state level tourney. Picked kids for all the weight such that no one having to cut any weight. Exception was heavy weight, only had one kid and he was over by think ~6lb. We had ~1.5 weeks, told him what to eat. Mid week of tourney checked his weight, was getting close, told him what to eat before we'd check at practice the next night. He comes back 2lbs heavier, ask him why what happened, said his mom gave him a Snickers bar.
There's a reason some kids are in the HWT category.