Make sure it’s the lucozade sport (or similar drink) fizzy lucozade will just end up coming back up. Easy to eat foods that can give you a quick sugar rush, sweet, sugary cereal bars are good for a quick boost but also ones that give you a sustained release like bananas, protein bars etc. Also pack some plain dry stuff, crackers, salted crisps etc for the event that you do feel a bit sick
Jelly babies
Coconut water
Dates
I literally have lucozade and cereal bars as last time I packed loads and that’s all that I touched xx