If you can spring for it buy some high protein beans or lentils or some other legume and mix them, almost every society on the planet no matter the geography invented rice and beans because it’s so damn easy to store for long periods of time and will get you the protein and calories you need to survive.
Is it fun? No. But it will get you fed and it’s an excellent base to throw in other things to spice it up. Get a little extra money and can afford a bit of meat and veggies? Sauteed them up and you get a full blown meal with a side dish and a porkchop/fish filet/chicken breast with your rice.