6 large potatoes
an acorn squash
1.5 cup rye, barley, or buckwheat porridge
1 cup carrots
8 oz. collards
1 cup green beans or peas
1 cup cooked fava beans, or other legume
2 T hazelnut oil
The following supplemental animal foods would be eaten weekly:
6 duck eggs
6 oysters (12 oz fresh weight)
10 oz mussels (fresh weight)
The result is a diet that contains 2000 calories per day: 70g of protein (12% of calories), 45g fat (19% of calories) and 350g carbs (69% of calories). Fat calories come primarily from monounsaturated fat, with 7g of polyunsaturated fat (3% of calories) and less than 6 g of saturated fat (2.5% of calories). For comparison, the American Heart Association recommends less than 7% of calories from saturated fats. I'm not convinced that saturated fat is harmful in moderate quantities, but this amount should satisfy all but the most extreme anti-fat crusaders. The omega-6 to omega-3 ratio of the diet is 3.8:1, which is favorable, and even more so when one considers that most of the omega-3 is marine, long-chain omega-3 (from shellfish). If more calories were necessary for some reason, the calories could come from additional potato consumption.
The diet is also sufficient in all micronutrients, in most cases supplying more than the RDA. Besides calcium and choline, both supplying 100%, all other micronutrients are in excess of 120% of the RDA. This includes commonly deficient micronutrients like magnesium (680 mg, or 170%), potassium (7.5g, 160%), selenium (100ug, twice RDA), and zinc (18mg or 163%). Vitamin K and vitamin B-12 are the two most abundant micronutrients; both supply well over 500% of the RDA. That's good considering their low toxicities and the dangers of deficiency.
The math involved in figuring the amount of space necessary per person on this nutritional regime is complicated, especially considering that land may bear multiple harvests in a year (for instance, if fava beans were overwintered on the same soil that bore summer vegetables), the complexity of soil conditions and climate. I'm no expert in gardening, let alone shellfish farming, and I would even question the logic of coming up with a seemingly precise figure balanced on dozens of flimsy assumptions.
*In the nutritional analysis, I used 1 lb strawberries and 2 lb raspberries per week. Berries grow great in our local climate, as the vigorous raspberry patch flowering outside my window attests.
Note: much of this information is derived from what I have seen at farmer's markets, assuming that the foods sold there reflect what grows efficiently in our climate. Also, I have to thank Stephan Guyenet's posts on gardening and our own (much smaller and less efficient) urban garden. We grow tomatoes (not suited to the climate!) raspberries, blueberries, and herbs. We used to grow strawberries and are now growing kale and swiss chard.