lets say you have atleast some access to food, because it's difficult to plan for an all encompassing catastrophy, there are certain combinations of food that are considered complete or that provide all 20 amino acids (essential and nonessential). for example, eating rice, beans, and corn together provides all 20. there are others but I dont know them off the top of my head... i think another is rice, seaweed, fish (sushi). but rice, beans, and corn could be kept in pretty large quantities without spoil pretty easy.