This "cornerstone" strategy uses four items as daily (or almost daily) sources of the three macronutrients: protein, fat, and carbohydrates. Various types of vegetable oil provide dietary fat. Wheat (e.g. pasta, flour) and rice provide plenty of carbs and some protein. Then you just need a good source of supplemental protein for the foundation of your diet.
Note well, these four items are not all that you eat. They provide only the foundation of your diet. You can survive for a long time on those four foods, because they provide all the protein, fat, and carbohydrates you need. But to survive and thrive, you need many other foods (perhaps from a survival garden and a well-stocked chest freezer).
1. Vegetable Oil
Dietary fat is an essential nutrient. Despite the many messages in media today, touting low-fat foods and low-fat diets, you need fat in your diet to survive. And, after the SHTF, if you are more physically active, fat is not only an essential nutrient, it is a good source of calories.