Should we eat the old people?

Based on numbers from Vogel’s book “Prime Mover: A Natural History of Muscle” (W.W. Norton & Co., 2002), a human body on average can provide around 45 pounds of slightly fatty meat and other edible parts. (An all-meat diet, if organs are consumed as well, can supply all the body’s nutrients, as demonstrated by Eskimos.)

Those victuals translate into about 60,000 kilocalories. Humans need 2,000 to 3,000 kilocalories a day for sustenance. (The “calories” listed on nutritional labels are actually kilocalories.) Assuming there was barely enough chopped-up man-meat to go around and the cannibals were getting only 10 percent sustenance per day based on a 3,000-calorie diet, a single person could provide 200 days of sustenance to the person who eats him.

Even so, Vogel writes, “a population would have to sacrifice nearly two of its adults each year for each of its (surviving) members. That means [the population] would decline by almost an unthinkable two-thirds each year.”