Human race will die out in just over three years if all of us turn cannibals.Wikimedia Commons

Imagine a world where there is no food for us to feed on, and the only way to survive is to resort to cannibalism. A group of British researchers has envisaged such a dire situation, and calculated that humanity will die out in just over three years in a "man eat man world."

As part of the research, the scientists took into account how many calories a human is comprised of, and estimated that each human would consume exactly 2,500 calories a day. They also used a decay model to predict that only one person would be left alive 1,149 days after the human race starts to eat itself.

"There are currently 7.6 billion people on Earth. In this paper we present a hypothetical situation in which all food has been removed from the surface of the Earth, and humans have resorted to cannibalism in an attempt to survive. We will calculate how long the human race could survive if it had to resort to cannibalism and eat only human flesh," the scientists said in a study, recently published in the Journal of Physics Special Topics.

When it comes to the nutritional value of human flesh, it's not packed with calories for their size. Compared to boars and beavers packing nearly 1,800 calories into each pound of muscle, it will be only 650 calories in the same about of flesh from a modern human, according to a previous study.

In the new study, scientists have calculated the total amount of calories in the edible parts of an adult male human body to be nearly 126,000 calories. Based on the calculation, the scientists suggested that if the average number of calories consumed per person per day is 2,500, one human body will be able to feed 50 people in a single day. Each day, therefore, the population of the world will decrease to 50/51th of its size compared to the day before.

Scientists also said that they haven't taken into account the logistics of the situation, assuming that the edible body parts have been shared equally amongst everyone left on the planet. They have also imagined that people will be grouped together in one place when the population is low in numbers.

"Having an all-meat diet would have no adverse effect on your health provided you ate a variety of components from the food source, e.g. liver or kidneys. However, you would be at risk from contracting Prion diseases, which you get from eating human brains," scientists said.