Knowing what to buy as far as survival supplies go is relatively simple. You know that duct tape, para cord, and sheet plastic all have hundreds of uses. You know that it is a good idea to buy a battery operated radio, have flashlights on hand, and that you can never have too much ammo. But when it comes to planning for your emergency food needs, the mind boggles.
Basically I stock up on food that we will eat anyway (canned soup, canned meat, canned vegetables, and grains along with some MREs and freeze dried food on the side that can be used for the occasional backpacking trip). The problem comes when you try to plan for long term food needs, say of about a year or so. That is often as far as most people get before they become overwhelmed with what to buy, how much to buy, how to store it, etc. When you start to calculate calorie needs per person, per day, for 365 days, along with assuring an assortment of food that covers all of your macro nutrient and micro nutrient needs...well you can see how people can end up throwing up their hands.
And then I watched an episode of Surviving Disaster that gave the most succinct explanation of long term food storage that I ever heard of. It was such a simple idea I nearly fell off of my chair. Basically what the guy said is that for three months of food for one person at 1800 calories a day, you need three gallons of oil, 100 6-ounce cans of tuna fish, and a 20 pound bag of rice. This simple stockpile would cover all of the fats, proteins, and carbs an average person would need to survive for three months. Aside from the fact that should you be forced to live on this food, you would never want to see another tuna fish or grain of rice again, the concept simplifies emergency food storage to something that everyone could understand and do. For a year's worth of food, simply multiply these items times four.
If you can't fathom eating these three items for a year (and you are worried that you will miss some significant dietary nutrients), consider how you can substitute items that fall into the three categories.
For fats, consider: butter, mayonnaise, salad dressing, cheese, milk (dried), meat, nuts, eggs.
For protein, consider: meat (dried, canned), fish (canned), milk (dried), eggs, beans and rice, soybeans.
For carbs, consider: rice, whole wheat flour, beans, oatmeal, barley, pasta.
You'll note that some of these foods overlap categories (ie: canned sardines packed in oil cover both the protein and fats categories). Throw in some canned/dried fruits and vegetables and some spices and you will be set. Also, don't forget a good multi vitamin.
The bottom line is that emergency food storage doesn't need to be overwhelmingly complicated.Theoretically someone could go to Costco and buy 100 pounds of rice, 15 gallons of oil and 400 cans of tuna and be set for a year. Most of us like a bit more variety in our diet and would substitute canned sardines, beef jerky, Spam, beans, and other sources of protein for 300 cans of the tuna but when you look at the simple equation that makes up your food needs, everyone should be able to have enough emergency food stores on hand to carry them through both short and long-term disasters where your food supply could be interrupted.