It is a fact of life that you cannot live off of meat alone indefinitely. And though you can often find black walnuts, pecans, and other nut trees to forage from, there is no nut tree as common as the Oak. Acorns, the product of the Oak trees, are prevalent, and if you could just eat them as is, then survival would for the most part be pretty easy as far as gaining food goes. You actually can eat them as they are if you don’t mind the bitterness and it is a funny sidenote to add that in the movie Jeremiah Johnson, the item that Jeremiah’s Indian wife gave him to eat that made him gag was an acorn cake which hadn’t had all of the tannic acids leeched out.

Making acorns palatable:

1. Shell them. This is easiest done on a large rock with a smaller one. Separate the meat from the shell, and then grind the meat to flour with two stones.
2. Leech the tannic acids. You can boil them out, changing the water periodically as it gets discolored. Make sure the water is at a boil each time you put the meat in, as going hot to cold tends to lock the tannins in for some reason. Another method is to put them in a sock and let it seep in running water for a time. This will remove the tannic acid and distribute it into the water source. You are losing tannic acids which are useful if you do this.
3. After leeching the tannins out, make cakes out of the flour. These will be coarse and dry when done. A better acorn bread involves flour of some sort being added. However, these acorn cakes are very nutritious, high in energy and carbohydrates, and will hold you over for a while. I can imagine they are delicious with maple syrup.
4. Bake on a rock over your coals.

As a side note, if you boil the tannic acid out of your acorn mush, make sure that you save it. It can be re-used as antiseptic, tannic acid for hides, or a low grade dye for leather.