“It’s a Man Eat Man World”, Holly Graham, William Sainty, Sam Kneeshaw, Simon Howard-Clark2017-11-19 (biology, STEM humor)⁠:

[cf. rocket equation, jeep problem] In this paper we calculated how long the human race would last if it resorted to cannibalism and only cannibalism.

We took into account how many calories a human composes, using the value for an average human male, and that each human will consume exactly 2500 calories a day in accordance with the recommended calorie intake for men.

Using an exponential decay model, we found that 1 person would be left alive after 1149 days.

…We shall also assume that the average number of calories consumed per person per day is that of an average adult male: 2500 calories, meaning that 1 human body feeds 50 people a day. Each day, therefore, the population of the world will decrease to 50⁄51^th of its size compared to the day before.

…Using Equation 4, we calculate that it would take 35 days for humanity’s population to decrease by half, and by the 451^st day only 1 million would remain. As the population approaches 1, the number of people being eaten dramatically slows, as shown in Figure 1. It would take 116 days to go from 10 people left alive to just 1, which is found by substituting y = 10 and y = 1 into Equation 4.