Provide your own vegetables at 70-80 m2.
selfsufficiencySelf-sufficiency is the easiest for fruit and vegetables. Which consist largely of water, so you can get high yields per square meter. You must of course always eat yield of the season. Unless you have a greenhouse, so you can forward and stretch the season. A man needs about 400 grams of fruit and vegetables a day meaning 146 kg food per year.
The garden produce can vary from one to four kilograms per square meter. With intensive use you can grow vegetables twice a year. The yield can increase by choosing productive vegetable species (carrot: < 10 kg/m2) and intensive cultivation. Plan for winter cabbage, sauerkraut or carrots.
With an average of two kilogram of yield per square meter, so you are at 80 square meters that you need per person. With good soil, humus, timely and sufficient water to make even better.

Bread, potatoes and pulses, largely estimated at 250 square meters.
An hectare of potatoes can yield more than sixty tonnes. For one person, so you need approximately 15 square meters. An hectare of wheat produces less food, but also straw. Winter wheat is sown in the fall and brings about nine tonnes per hectare. For one person, so you need hundred square meters.
The amino acids in cereals and legumes are complementary. Eaten in a 3:1 ratio you get basically all the amino acids in the right ratio on your plate. Because pulses per square meter yield less than grain the required surface is similar. Pulses, potatoes and cereals are grown in rotation. Legumes put nitrogen in the soil. Compost and (even your own) fertilizers are certainly needed in order not to exhaust the soil.

Oilseeds: count on 30 square meters
A small amount of polyunsaturated fatty acids in your diet is absolutely necessary. The Nutrition Center recommends 15 grams per day. Per year this is about 6 liters or 5 kg. A healthy oilseed crop in our region that grows well, is rape(seed). It produces per square meter half a kilogram of seed, good for 200 grams of oil. The remainder is more than 3 kg press cake. That is edible or for use as animal feed. Other healthy alternatives with slightly lower yields are flaxseed, sunflower and rapeseed.

Meat, milk and other animal products are tripling the necessary surface. The animals have need of housing, pasture and winter feeding.
Pork has a feed conversion of 5:1. For a pig around 500 kilo of grain and other crops are annually needed. The advantage is that they eat everything, even what we do not lust: grass, acorns, guts, spoiled food...
Per person have one or two chickens that also lay eggs advantages. Food scraps and rapeseed cake can be fodder. They scavenge themselves a lot together: seeds, insects...

An interesting addition is a fish pond. In a reservoir undemanding fish like carp or freshwater grass carp can be kept.

According to local tradition, a small family (2 children) on the poor Campine sandy soil would have to cultivate 2 hectares of land in order to provide for a living (with 1 pig, 1 cow). To provide them with manure, 14 hectares of heathland and sheep were needed. And bees.