Part 3 · Subsistence First
The Subsistence Equation
Work backward from the household's calories, protein and fat to the kilograms and then the square metres. The arithmetic of a subsistence system, with the fat gap that most plans miss.
A subsistence plan that starts with a list of vegetables is a plan that will fail, because it never asked how many calories the household actually eats. Start from the people. Work backward from what a body needs to how many kilograms of food that is, and from the kilograms to the square metres of ground. This lesson is the arithmetic the whole of Part 3 depends on.
The subsistence curriculum in the vault states the equation as a chain: available land, times soil productivity, times climate, times water, times labour, times crop selection, times storage, times nutrition, times risk, times external inputs, equals household subsistence capacity. Read it as a sentence about limits. Any factor at zero gives zero capacity. The arithmetic below fixes the nutrition term and shows how the others scale it.
Calories first
An adult needs about 2,000 kilocalories a day. Multiply by 365 and that is 730,000 kilocalories a person per year. That is the number the farm must grow, before any loss.
Then convert calories to kilograms. Different crops carry very different calorie densities, and Pelman's own table, which reports daily grams and daily calories for each crop, lets you derive them. Read straight off his figures: wheat at 125 grams and 426 kilocalories a day works out to about 3,400 kilocalories per kilogram. Fava beans at 225 grams and 768 kilocalories is about the same, roughly 3,400 per kilogram. Olive oil at 65 grams and 526 kilocalories comes to about 8,800 per kilogram, because oil is nearly pure fat. Those conversions are arithmetic on his published table, not new data.
Then convert kilograms to ground. Wheat yields about 0.24 kilograms per square metre in his field, fava the same, olive oil close to 0.9, and the vegetable garden about 3.8 because vegetables are mostly water. So the whole chain runs: needed calories, divided by calories per kilogram, divided by yield per square metre, equals square metres of that crop.
His whole system, taken together, produces about 1,000 kilocalories per square metre per year. That one figure is the most useful thing in this lesson, because you can scale it to any household and then adjust it down for a harder climate.
Protein second, and why the pair
An adult needs on the order of 105 grams of protein a day in a diet of this kind, and Pelman's system delivers exactly that. But protein is a completeness problem, not a quantity one.
Neither of the two staple crops supplies complete protein alone. Grain is low in lysine. Legume is low in methionine. Eaten together, in the same day, they complete each other, which is why rice and beans, or wheat and fava, or maize and beans, recur in every farming culture on earth. A plan that grows grain and no legume, or legume and no grain, feeds the household a protein that the body cannot fully use.
In his table the legume carries the larger share: fava supplies 59 of the 105 grams a day, wheat 16.5, and the vegetables 30. That is why the legume plot is the biggest single block on his farm, 350 square metres against the wheat's 200.
Fat third, and the gap nobody plans
Fat is where most home plans quietly fail. At 30 percent of a 2,000 kilocalorie diet, a person needs about 67 grams of fat a day. Pelman's system supplies about 70, and almost all of it comes from one line: 59 grams from olive oil. The grain and legume together give 7.5 grams.
This is why an oil crop is not optional in a subsistence system. Vegetables and grain are bulky and watery and cannot carry the fat. The oil tree or oilseed is the densest thing you will store, and it is the line most garden planners forget entirely.
Micronutrients, and the honest shortfall
Calories are not the same as nutrition. Never evaluate a subsistence system on calories alone. Pelman's farm meets or exceeds the recommended intake for a 70 kilogram adult on every measure the 2024 study checked, with one exception: calcium, at about 80 percent of the recommended intake. That shortfall is real and it is his, and it tells you that even a decade-old, peer-reviewed, well-planned system can run one nutrient short. Plan for the gap, test it, and close it deliberately, whether with a mineral source, more leafy greens, or small animal production.
Exercise
Run your own equation
Using the baseline from lesson 301, compute your household's annual calories. Pick three crops you can actually grow: a grain, a legume, an oil. For each, look up its calories per kilogram and its realistic yield per square metre on your soil. Divide calories by calories per kilogram, then by yield, to get the square metres each crop needs. Add the three areas and write the total. If you cannot find a yield figure you trust for your soil, write the field number you will measure this season.
Exercise
Find the fat gap
Take your daily fat target, about 30 percent of your calories divided by nine. Sum the fat your planned crops supply. If the oil crop does not cover most of the gap, your plan has a fat hole. List two oil crops that will grow in your climate, one annual and one perennial, and note the year each first yields.
Fieldwork
Weigh a week of food
For seven days, put every item the household eats on a kitchen scale before it is cooked and write the weight in grams in a notebook, one line per meal. At the end of the week, total each food by category: grain, legume, oil, vegetable, animal. Take the label's calories per hundred grams for each and work out the household's real daily calories, protein and fat. That table, not an estimate, is the base of your subsistence equation.
Failure mode
The calorie-only error, and its twin, the protein-and-calorie plan with no fat. A pantry can clear 2,000 kilocalories a day and still leave a household deficient in fat and in calcium, because calories, protein and fat are three separate budgets that must each be filled. Track all three, and track calcium, or you will build a system that feeds a body but not a healthy one.
