I'm sorry, I didn't have time to read all answers, but I'd give my input anyways as far as eating goes.
I just asked about beef jerky in the nutrition part of the board, and I was suggested to buy a dehydrator. GOD I LOVE THIS THING. Best purchase of the year.
So I'd like to suggest the same to you right now. Amazon has a pretty cheap one, around the 40's, that way you can create a good amount of beef jerky for very low price, and you can always carry a little sandwich ziplock to class and munch on it in between classes and so.
And if you want to have some carb with it you can easily do it do, get some wheathins and crush them, mix it with ground beef before you make the jerky and bam, you have protein and carbs for snacks!
Might be worth the try for you.
Good luck.