Dura Lex Sed Lex

1a: The size of mammals (blue dots) is shown in relationship to their metabolic rate. For humans, the metabolic rate varies considerably (red dots), but is on average (star) much higher than expected. Human weight is set here at 50 kilograms. 1b: While life expectancy among humans rises along with energy consumption, the increase is less than would be expected for a mammal with the same metabolic rate (compare dashed line). 1c: Birth rates decline with rising energy use roughly equally among humans and other mammals. 1d: With rising per capita energy consumption of a country, the gap between the birth of the first child and the onset of menopause is decreasing.


Humans need to eat around 2,000 calories per day, but the average person in industrial nations burns more than 32,000 calories a day. In wealthy industrial nations like Germany, the average energy consumption of an individual is 110,000 calories, which is still only half of the U.S. value. Because he only eats a small portion of the energy he uses, this level of energy consumption has little effect on the individual’s weight. It does, however, influence his demographic traits, such as lifespan and birth rate, Oskar Burger of the Max Planck Institute for Demographic Research has found in a new study. And this enormous energy usage could even explain the low birth rates seen in highly developed countries, according to the author and his collaborators. https://www.mpg.de/5880006/energy-consumption-birth-rate