An online friend and I have had a long back and forth about family food supplies and how long they'd last in an emergency. She specifically wanted me to gauge about how long her own pantry supplies would likely last her, not in days but perhaps weeks. So we came up with a system for quickly gauging how long a pantry would last a family if they had to stop buying food for a period of time. I thought I'd share in case any one here has ever seriously wondered how long their pantry would keep them fed in an emergency.
Step 1. Determine the household's caloric need per day. Here's a basic guideline from Bowes & Church's Food Values of Portions Commonly Used:
calories needed for adults
women 1800-2100, men 2400-2900
calories needed for children
under 10 years up to 2400
calories needed for teens
teen boys 2700-2900 teen girls 2100-2200
add on for nursing (+500) or pregnant (+300) women
My friend's household consists of herself, husband, 20 year old daughter living at home while attending local college, 15 year old son at home. We factored in activity level for each individual (very active son, sedentary self and spouse, moderately active daughter) and came up with about 9500 calories per day for their family.
Step 2. I asked my friend to inventory her pantry, her fridge, and her freezer for calorie-dense basics, such as flour, rice, dried beans, oats, hot cereal, oil, peanut butter, raisins, other dried fruit, sugar, nuts, meat (and I asked her to specify whether it was bone-in or boneless and whether poultry, red meat, pork), eggs, butter/margarine/Crisco, and cheese. I asked for rough measurements by pound, not boxes, bags, or servings.
We weren't going to concern ourselves with items like crackers, boxed cereal, canned vegetables or fruit, or condiments, unless she felt she had an extraordinary amount of any of those. (It turns out she did have more than average number of jars of mayonnaise (9 jars --long story), and we felt since this was a high fat item, in an emergency she could use the mayo as part of the daily fat for her family.) The cookies, crackers, and cereal would likely be gone in a few days if she halted shopping, and the canned veggies and fruits, while they would boost nutrients and add interest, they wouldn't be as calorie-packed as some of the other foods. Ditto on frozen meals and frozen veggies. We did leave in raisins and other dried fruit because a pound of raisins provides almost enough calories for one person for one day.
Step 3. While my friend compiled a list, I jotted down the caloric values for these products, using units that the items are usually sold, such as pounds, gallons, dozen instead of per serving. I rounded the numbers to make calculations simpler. These are just estimates for the average in each group. Here's my list:
pantry
dried grains -- average calories per pound (inc rolled oats, rice, flours, meals, dried pasta), about 1600
sugar -- calories per pound of sugar 1750
dried beans -- average calories per pound 1500-1600
vegetable oil -- calories per gallon about 33,000
dried fruit -- average calories per pound 1300-1600
peanut butter or other nut butters -- average calories per pound about 2600
shelled nuts and seeds -- average calories per pound about 2600
mayonnaise -- average calories per 30-oz jar about 5300
meats
bone-in poultry -- average calories per pound (mix light and dark) about 750-1000
boneless poultry -- average calories per pound (mix light and dark) 500-700 (depending on type and with or without skin)
bone-in red meat -- average calories per pound around 1000 depending on leanness
boneless red meat -- average calories per pound around 700 - 1250 (depending on leanness)
bone-in pork -- average calories per pound about 700-1000
boneless pork -- average calories per pound about as little as 475 (deli ham) - 700 (pork loin)
pork breakfast meat -- average calories per pound 1400-1800 (sausage and bacon)
fish -- average calories per pound 350-650
dairy
solid fat -- calories per pound (butter/margarine/shortening) 2400 to 3200
liquid milk -- average calories per gallon (as is or reconstituted dry) 1300, 2000, 2200 (skim, 2%, whole)
eggs -- average calories per dozen about 840
cheese -- average calories per pound about 1300-1700
Step 4. We combined like foods, such as flour with rice and pasta, to simplify calculations. And we used the arithmetic mean value for calories for each type of meat. After totaling the approximate calories for the items in my friend's inventory, I divided by the daily caloric requirement for her family. We were able to roughly guess just how long her food storage would last her family should she not be able to grocery shop as usual.
As mentioned above, for expediency, there were many foods that we didn't include, such as jarred applesauce, canned soup, canned vegetables, breakfast cereal, etc. Most of those items were in single quantities or have relatively low caloric value. Those foods would increase the time my friend's pantry would last their family, but likely not more than a few days.
This wasn't just a mathematical exercise. My friend and her husband are currently digging themselves out of debt from a struggling business during the shutdowns. They accepted loans from family members to get through the worst and now that business is back up and doing better, they want to repay those generous relatives. My friend was thinking they could make an extra payment or two to both family members in the coming months if they had enough food to live on, or near enough (she could buy some high-nutrient vegetables, fruits, and milk, while spending minimally). As it turns out, she has enough in her pantry and freezer to last about 12 weeks. I suggested they hold back about 4 weeks worth of food for that proverbial rainy day, if their relatives don't need the loaned money immediately.
My friend had a lot of flour and other grains. She bakes their bread and other goodies in place of buying packaged items. She's also been trying to eat more vegetarian meals, so they had a lot of dried beans in stock. Her husband and son eat a lot of meat, though. However, hubby hunts and fishes and filled a deep freeze this past fall (and there's still a lot of meat left, I'm told). Despite their difficult times in the past couple of years, they really did have quite a lot of the types of food that one normally associates with emergency planning. In addition to holding onto a 4-week supply, I also suggested they not eat all of the ready-to-eat items, such as canned soup, crackers, peanut butter, and breakfast cereal. Instead, she should put some of those items away separately, in case of a power interruption that would affect cooking meals.
It should be noted that just because one has enough calories for their body's energy needs, the diet may not be balanced. This list isn't a prescription for what to include in an emergency pantry. I'd assume one would add various other foods that meet vitamin and mineral needs.
p.s. we came up with a couple dozen ways my friend can incorporate mayonnaise into their weekly meals, using the other ingredients she has on hand.