Carrying Capacity and the Fat Problem

Ask how many people a plot of land can feed and the reflex is to answer in calories. That reflex is the reason most land calculations are wrong, and wrong by a large factor. Carrying capacity is set by whichever requirement runs out first, and on a small mixed plot it is almost never calories.

The farm's engine was built to find that out. The worked example is on the record: a one-hectare plot in the standard mix, wheat at 0.4 of the hectare, fava at 0.3, olive at 0.1, potato at 0.2, measured against an adequate standard of 2,200 kilocalories, 55 grams of protein, and 50 grams of fat per person per day.

The number

The engine computes the edible yield of each crop, converts it to calories, protein grams, and fat grams, and divides each total by the annual requirement. The result:

• Calories feed 10.5 people.
• Protein feeds 18.7 people.
• Fat feeds 3.7 people.

The plot is limited by fat. A design that reads only the calorie line would call this hectare a home for ten people and then watch the fifth of them sicken on a diet that had run out of the one macronutrient the other two lines never counted. This is the single most useful number in the whole course, and it is the reason the engine flags a fat gap instead of a calorie gap.

Why fat behaves differently

The staple crops do not carry fat. Read the crop file and the pattern is immediate. Winter wheat holds 2 grams of fat per pound, fava 4, potato 1, dry beans 4. Calories and protein can be grown on grain and legume ground. Fat cannot be grown on that ground at all, because a grain plant stores starch, not oil. Fat comes from a different class of crop: oilseeds, nuts, olive, and animal fat.

The engine's data shows what that costs. Sunflower seed holds 100 grams of fat per pound and yields about 40 pounds per 1,000 square feet on loam, so 1,000 square feet returns 4,000 grams of fat. A person needs 50 grams a day, about 18,250 grams a year, so the fat alone for one person takes about 4,600 square feet, a tenth of an acre, and that is before the seed reserve and the drying loss. Hazelnut holds 170 grams of fat per pound and yields about 35 pounds per 1,000 square feet, so a planted nut block meets the same fat need on about 3,000 square feet, seven hundredths of an acre. Walnut, at 160 grams per pound and 40 pounds per 1,000 square feet, lands in the same range.

Compare that with the whole calorie requirement. A person's 803,000 kilocalories a year come off about 13,000 square feet of wheat on the same soil, a third of an acre. Fat for the same person costs a tenth of an acre in annual oilseed and about the same calories per square foot as wheat if you plant nuts. The land is affordable. The catch is that the fat crop is either an annual that competes with staples for the best ground, or a perennial tree that bears nothing for four to eight years. There is no third option that puts fat on the table this winter from grain ground.

The fat crops are slow and they need a press

Read the infrastructure as well as the crop. Olive is not a tree you plant and forget. It is a tree, a harvest window, a press, and a set of jars, and Cato budgets for all of them. The engine carries olive at a perennial ramp, first harvest in its own time and full yield only at maturity, because a young tree feeds nobody. Pelman's farm puts the fat on 9 olive trees and 45 square metres of net ground, and even there the yield is variable by year. This is why the fat question is the hardest one: it is the nutrient that needs the longest lead time, the most processing equipment, and the most forgiving climate of anything on the farm.

The open question

Whether a diversified low-input system can supply adequate dietary fat on one acre is a live research question, not a settled one. The engine's fat-limited carrying capacity shows what the standard mix delivers today. Whether better nut and oilseed integration can raise it, and by how much, is exactly what a working farm can test. Count your own fat line first, because it is the line that will fail first.