The basic diet is rice, beans, bancha tea, seaweed, and canned chicken soup. Your needs will vary according to your appetite. However, as a basic guideline the average adult will need the following amounts in reserve to cover a 3-month period: 2-3 lbs. each of pinto, black, adjuki, and northern beans, and 20-30 lbs. of rice.
Seaweed can be purchased in Asian food stores very inexpensively and integrated into soups and salads. (The Japanese hijiki salad is my favorite and a tasty way to include seaweed in the diet. I found a large block of wild laver in an Asian market for $5 which can be reconstituted in water for addition to soups.)
Bancha tea is a roasted green tea; you will need approximately 1 box per month or 3 boxes per person (teabags can be reused for a yield of two cups per bag).
Chicken soup should be eaten daily and bought in cans to sustain the timelines needed. You will need approximately 80 - 90 cans of soup for a 3-month period. Remember, more or less as you wish and additional foods are okay.
REMEMBER TO CHECK YOUR EXPIRATION DATES ON FOOD ITEMS AND REPLACE AS NECESSARY.