@kaia @lain people should ask ME. a hobby-specialist in this kinda stuff

a person needs ~~3 snickers a day for motivation if all days are hard physically, 2 if they are moderate, 1 if they are full rest a day.
thats ~~~<900 snickers a year per person
one snickers is roughly 55g

so per person you need to hoard ~~<50 kilograms of snickers (equivalents are fine too, such as muesli bars, bounty, mars, milky way, skittles, sour candy, etc etc etc) a year per person

so a four person family, in a 2 year shelter, would require something like 400kg of snickers [equivalents, cookies, all ok]

next up, GRAINS
going safe, 150kg of grain per person per year, and it better be grain you actually eat day to day. so prolly like 80+-kg wheat (includes pastas), 30 kg rice, 30kg oats, 10kg "other" grains would be my setup, so thats 1200 kg of various grains for 4 people 2 years. "Other" could be pre-mixed pancake mixed, etc etc.

how much travel? MREs one per person per estimated day of big travels a year. Estimate 2 MREs a week is usage(random low-end asspulled number)
~~110 MREs total

various room-temp OK spreads (peanut butter, chocolate spread), one jar a month? 24 jars

probably something like 5-7 liters of cooking oil per person, so 40 liters total

so thats
40 liters oil
1200kg grains
400kg snickers
110 MREs (81kg)
so thats like 1750kg of foodstuff that needs to be changed every 2-3 years to stay at good prep at all times

say the average foodstuff costs totals to 10€/kg (haha) then thats 17500€ / 3 years = ~~6000€ a year expenditure to keep a fresh prep supply ready at all times

assuming the prepper family eats half of that properly and food doesnt get wasted, ~~50% of that expenditure is saved yearly into normal food costs

stopping this post now