Food prep math...

[suburbindigenous]

I'm still new to all of this and haven't started REALLY storing any food yet. I have just gotten into the habit of buying an extra 1 or 2 of something, which has gotten my pantry a few extra cans of diced tomatoes, tomato sauce, and tuna.

The analyst in me wants to figure out exactly how much food I need to store to be secure for however long I decide to be prepared for. Let's say my goal is to have enough food stored for 3 months for the two people in my household. I guess I could figure our average caloric intake is about 2,000 per day and figure I need 180,000 calories of food at hand. Then I would need to figure the amount of calories in each of my stored items...

Is this really what people are doing or am I going about it the hard way? I don't eat grains or beans, so I think my high-calorie staples will be meat, nuts, and fats. I do have about 3 lbs of butter in the freezer. It's a start!

[MTUCache]

While going by calories appeals to my mind as well, being an engineer, I do see that as a bit of over-thinking.
It may be better to go by cans/meal and meals per day.

While calories are the fundamental use of food, there's other considerations that will take priority (hunger, nutrients, etc).
A big tub of multi-vitamins will take care of some of that, but you still need to figure out things based on food groups, calorie-density, etc.

I try to divide mine up into complete "meals" for my family of four:
* one pound meat, two cans tomatoes, two cans beans and two cups rice is a pretty generous meal
* one pound meat, one jar sauce, one pound of pasta (again, a big meal)
* one pound meat, one jar sauce, two cups of rice
* 6 packets of oatmeal, 6 eggs

How many meals we're going to need per day (2-4) is going to depend on what kind of activity we're doing, how much time we have, as well as what level of hunger we're able to stand.
When SHTF you're going to have to decide whether you're staying on full-rations, going to half-rations, or even double-rations to get through that scenario.
Maybe some days you get only one huge meal while others you're snacking constantly through the day.

Bottom-line, your energy requirements are just one aspect of food. Being able to gradually get your family down to 1200 calories/day is a lot more difficult than just announcing it at a family meeting, especially if you're going to expect them to be doing physical labor that they're not accustomed to. Nobody is expecting scurvy to set in after a couple weeks, but if rice/beans/meat/cans is all you've got things are going to get desperate REALLY quick, if only for a chocolate bar and a fruit cup. 

[Alpha Mike]

I imagine there are a variety of methods people employ to calculate their LTS food needs. I believe having some inventory of you LTS food is important.  Just use what every system you feel comfortable using.
 
Myself, I am doing something similar to you.  Mine is on a spreadsheet with the calorie count and a conversion estimating the number of days supply (I have not created any graphs or charts yet )  That said, I still have to manually ensure that I have complete meals as well as a variety for foods and flavors.  I also include purchase date / expiration dates.

No mater how you track your food stores, Just remember some basic rules.
  Realistic amount of food for the work at hand.  You may be working harder after the collapse/disaster.
  Balanced diet -  carbs, veggies, protein.
  Variety, variety, variety.  Appetite exhaustion sucks.
  Store what you eat (because you will be stuck eating what you stored anyways.)

AM

[Herbalpagan]

I do mine in complete meals...then when I got enough, I started adding more of the basics.
I started by grabbing extras of what I got, when there were sales...for instance, whenever there was a 10/$10 sale, I would get 20 and I would add whatever else was needed to make that item a meal (spaghetti 10/$10, I'd add the sauce as well). Once you get to three months of meals, you are at the point where you can shop exclusively on sales or coupons (they rotate every 9-12 weeks).
I noticed that doing this worked well except for bread items and meats...so I worked on that getting flour and canning meat and picking up canned meats like chicken (macaroni/rice+one can of cream of soup+one can of veggie+one can of canned chicken=delicious casserole). Oats for breakfasts or wheat for pancakes and muffins.
Keep working on it, learn how long things actually store and soon you will have a nice complete pantry.

[Transplant]

I do mine in complete meals...then when I got enough, I started adding more of the basics.
I started by grabbing extras of what I got, when there were sales...for instance, whenever there was a 10/$10 sale, I would get 20 and I would add whatever else was needed to make that item a meal (spaghetti 10/$10, I'd add the sauce as well). Once you get to three months of meals, you are at the point where you can shop exclusively on sales or coupons (they rotate every 9-12 weeks).
I noticed that doing this worked well except for bread items and meats...so I worked on that getting flour and canning meat and picking up canned meats like chicken (macaroni/rice+one can of cream of soup+one can of veggie+one can of canned chicken=delicious casserole). Oats for breakfasts or wheat for pancakes and muffins.
Keep working on it, learn how long things actually store and soon you will have a nice complete pantry.

That is how I started. I would plan my menu for the month then I would buy what I need plus enough for 3 or 4 extra meals. After a while I had 2-3 months supply. Since our move my supply has been some what depleted because for the last 3 months before the move I didn't buy anything. We wanted to get rid of the older stuff so we lived off our stock. I have bought only fresh stuff like milk and eggs oh and meat since we have been here. This week I get to start all over...plan the menu for the month and buy double.

[LibertyBelle]

I started off by tracking all the meals for one month and then based extras for my stores on that.  But then I realized that I'm a seasonal (for lack of a better word) eater.  For example it might be three months since I've wanted pumpkin/squash soup, and then suddenly I'm craving it at least a couple times week.  Or maybe it's just that I tend to eat something until I get burned out on it and then it may take a good 3 months or so before I feel like having it again.   So now, if I've eaten something (and liked it) at any time during the past year, I try to make sure to have a half dozen cans/jars/containers of it on the shelf.

[Wildthang]

I took the approach of stocking up on staples that allow us to cook different dishes by utilizing vegetables from our garden, fruit trees, and the chickens we have.
I bought the #10 cans with a shelf life of 20 to 30 years so we don't have to worry so much about rotating foods. I have lot's of powdered milk, flour, corn meal, tomatoe powder, cheese sauce, whole powdered eggs, butter powder, chopped onion, potatoe flakes, sugar, salt, baking powder, oatmeal, and several cans of various dehydrated vegetables and rice. I think that staples may be harder to get than regular foods if times get rough, so to me the staples are very important.
We also can a lot of stuff as well. One thing about living in northern Ohio, is if the SHTF in early winter, it will ne several months before the garden will start to produce so we try to keep at least 8 months of food on hand. We also have about 4 pails of the dehydrated meals just in case we run out of fresh vegetables.
On top of all of that, we keep a large supply of canned goods in the pantry which is about the only thing we have to rotate!

[Kayakmom]

Here's an idea that I had and thought was helpful.  I was putting together a week's worth of food for the family and I was having a hard time feeling it was balanced, especially with all the repeat meals.  So I took my iphone and pulled up my "myfitnesspal" app and plugged in the meals for the week. it then graphed out calories, calcium, vit A, iron, and so on.  I could see where we had deficiencies and try to adjust for that. 
there are other websites that will do this to that are generally geared toward dieting, etc, but the info is helpful.  another good one is fitday.com

[stry67]

Here's an idea that I had and thought was helpful.  I was putting together a week's worth of food for the family and I was having a hard time feeling it was balanced, especially with all the repeat meals.  So I took my iphone and pulled up my "myfitnesspal" app and plugged in the meals for the week. it then graphed out calories, calcium, vit A, iron, and so on.  I could see where we had deficiencies and try to adjust for that. 
there are other websites that will do this to that are generally geared toward dieting, etc, but the info is helpful.  another good one is fitday.com

I like that idea!

[BenAntireliant]

An Article by the University of Utah suggests that we typically eat the same meals 80% of the time.  I've started to document the 5 to 10 most common meals we eat for breakfast, lunch, and dinner.  Then I can calculate how much of each ingredient I'll need to store for a year's supply:
(X/Y)*(356 Days)*0.8
Where:
X = Amount of ingredient (ex. butter, flour, sugar, etc…)
Y = Number of meals (ex. 5 meals for breakfast.)
I'll then compare my list to what others have suggested.
A more in-depth explanation is here:
http://antireliant.com/long-term-food-storage-list/