Survival required the consumption of energy.
If one dismissed the electricity used by a television, then a man weighing 60 kilograms sitting on a couch watching TV all day would consume about 2000 kilocalories of energy.
If he were to engage in physical labor, he would need to consume even more.
Two thousand kilocalories, converted into electric energy, is approximately 2.3 kilowatt-hours.
This is the basic metabolic rate of a person for one day.
Of course, even with some exercise, the energy required would not be much more than this.
Even with high-intensity exercise, a person would only need about four kilowatt-hours a day.
Each gram of carbohydrates can provide about 18 kilojoules/3.75 kilocalories of energy for humans.
A person consuming 550g of sugar a day could maintain basic consumption.
