I have seen some misinformation in a few threads about calories needed, and I didn't want to derail those threads so I thought I would post here.
Most people are prepping for about a 2,000 calorie a day diet- which is what you need if you're moderately active now, aka sitting at a desk with an hour or so of working out three days a week.
When things go bad, your need for calories goes UP. A LOT. When I did distance bike riding I could go through 5,000-6,000 calories a day. Another thing to keep in mind is that getting not-quite-enough calories makes people CRANKY. Very, very, very irritable.
Working your butt off, society collapsing, etc is stressful enough without turning into a raging cranky monster and having everyone snapping at each other.
If you're going to be in a situation where you're going to have to shovel snow, cut branches, butcher hogs, etc, etc, etc- any sort of serious physical work- you need to double or triple the amount of food you're keeping in prep or you'll start loosing weight way too fast. Make sure you have enough fat prepped, because you'll need to eat a LOT of it to get the number of calories you're going to need to keep going.
If you think 2,000 calories a day will keep a man working hard going for long, you're sadly mistaken.
Here's a few things you might have to do and the caloric cost:
Shoveling is 612 calories an hour
Heavy farming (moving hay bales, cleaning barn) is 514 calories an hour Sawing logs by hand is 460 calories an hour
Carrying Logs: 748 calories an hour.
Chopping firewood? An incredible 1,156 calories PER HOUR if you do it fast.
So if you go out, shovel out some snow, dig a ditch for a latrine, muck out animal pens and take care of some livestock, cut down a couple trees, cut them into firewood, and stack the cords, this is what your day would look like.
2,000 calories- base metabolic load.
+ 612 for shoveling
+514 for farming
+460 for cutting down the tree
+748 for hauling the tree
+1,156 calories for chopping firewood.
That's 5,490 calories for 5 hours hard work. Add a few more chores in there and you are easily pushing the 6,000 calorie mark.
Plus side: eat lots of bacon, who cares if it's fatty?
Down side: you probably need a lot more food the first bit post-SHTF than you planned on, because a 2,000 calorie a day diet will. not. work.
This was brought to my attention from a book I'm reading on the biodome project, where they budgeted 2,000 calories a day per person, and forgot that working your butt off means you need more calories! There were some hungry, cranky, bitchy scientists inside that dome, and all the interpersonal problems flared far worse than they would have if everyone was well fed.
Hope someone finds this helpful.
PS- in other news, I'm going to cancel my gym membership and go get a couple of cords of firewood set up in my BOL. That's WAY more calories than my frikken elliptical, AND I get firewood!