I think we need to up the goal a little.
A quick google search showed potatoes have a 347 calories/ pound and yields for commercial farms in the US run between 24,500 and 61,000 pounds of potatoes per acre (http://kenoshapotato.com
). Using the bottom yield (24,500 lbs/acre) that would give us a bit over 8.5 million calories/per acre.
shelled corn yields around 15 million calories/ acre (average yield in the us is about 170 bushels/ acre, 56 lb/bushel, a bit over 1600 calories/ lb) 170 x56X1600 = 15,232,00 calories/ acre. (note, when looking up calories for corn, look up dried corn or corn meal. Sweet corn (not dried) has a much lower calorie/ lb due to the water. I used calorie data from https://www.nutritionix.com/food/cornmeal/lb
So, I'm guessing if you planted 1/8 acre of potatoes, 1/8 acre for corn, and 3/4 of an acre for all the cool stuff you want to eat (melon, squash, beans, peas, berries, etc.) you should make a million calories/ acre pretty easy. (Armchair farming is amazingly easy, no aching back, no bugs).
pinto beans can make better than 2 million calories/ acre. (average yield in Idaho is 1500 - 2000 lbs/acre (https://ipmdata.ipmcenters.org/documents/cropprofiles/IDdrybeans.pdf
) with about 1570 calories per dry pound). 1500 *1570 = 2.361.969 calories/ acre
Even lettuce can make more than a million calories/ acre (63 calories/ lb, 36,000 lbs/ acre (https://nevegetable.org/cultural-practices/table-15-approximate-yields
) for over 2 million calories/ acre.
I'm wanting to try this on my own property (Cache Valley, Idaho) next summer. I arrived in my new (hopefully final) home last August and am looking forward to planting a HUUUUGE garden. I'm in the process of buying the two acres of pasture behind me to add to the acre my house is on, over half of which has been goat pasture for many years. I've ordered 30 red maples (partly just for the color), 30 saw toothed oak and 30 mulberry trees for the coppicing or pollarding on part of the back lot. Also in the plan are lots of peach, plum, apple, pear and apricot trees as well as just about any kind of berries this area will allow. I'm hoping to do lots of rootstock with grafting for the fruit trees.
In addition to calories, I would be interested in the variety and quality of food I can produce as well as quantity. I am also interested in the energy input to raise the crop (both fossil fuel and norwegian steam (muscle). Maybe we could give extra points for variety and perennial/ self seeding foods that required minimal maintenance. As far as trees go, for the first few years I figure trees will not take up much space. As they grow and take up more space, we will have a conversion to more perennials, which is what we want in permaculture anyway.