Whats a very effective food for a pre meal to keep a person going for 2hs?

I need something to keep me going for my upcoming karate test, not supps or drugs, just food suggestions please.

Go with a whole pile of low GI carbs, mixed with a little fat, and a fair amount of protien. But to the best of my knowledge, it’s the low GI carbs that’ll give you ongoing energy.

peanut butter