Humanity’s exceptional relationship with energy began hundreds of thousands of years ago, with our discovery of fire.
Fire did much more than just keep us warm, protect us from predators and give us a new tool for hunting.
A number of anthropologists believe fire actually refashioned our biology.
“Anything that allows an organism to get energy more efficiently is going to have huge effects on the evolutionary trajectory of that organism,” explains Prof Rachel Carmody of Harvard University in Cambridge, Massachusetts.
She believes the decisive development was cooking.
The carbohydrates, proteins and lipids that provide our bodies with nutrition are unravelled and exposed when they are heated.
That makes it is easier for our digestive enzymes to do their work effectively, extracting more calories more quickly than if we ate our food raw.
And we figured out more ways to access the calories in our food – by pounding it with a rock, by grinding into a powder, or even just letting it rot – or of course by roasting it over a fire.
In doing so, we further increased the supply of energy to our bodies.
This allowed us to evolve even smarter brains, and the ensuing virtuous circle propelled our brains to the top of the class.