Potato yield appears to be around 300 cwt/acre. Cwt stands for ‘hundred weight’, which is 100 pounds in America. There are 278 calories in a 299 gram potato. 1 gram equals 0.0022 pounds so 299 grams is two thirds of a pound.
Thus, one acre of potatoes yields:
(300cwt / acre) * (100 pounds / cwt) * (278 calories/.67 pounds)
= 12 million calories
A human eats around 2,000 calories per day; or 730,000 calories per year.
Thus, one acre can feed sixteen people. Which means that I’m cutting it close.