To survive, we need 20 amino acids, of which nine are essential, that is. One thing is certain: the candidates would not include meat or most fruits and vegetables. Meat has no fiber or vitamins or key nutrients. Fruits and vegetables may contain vitamins, but they don't have anywhere near enough fat or protein, even if they're eaten in quantity.
Your body doesn't need as much as you think to stay alive, but you skip them at your own risk. If you've eaten so much of some food that you actually got sick and couldn't eat it again, here's what could happen if you depended on just one food to survive. When you eat a new type of food that you've never eaten before, your body will try to digest as much as possible, it will remember what type of nutrients the food contains and, in this way, it can cause cravings if you are deficient in some minerals, vitamins and even salt. It's not a good idea to eat the same food every day, although in a severe SHTF situation you're probably only dependent on one or two types of food to survive.