Food on Earth Could Run Out, Requiring Humans To Eat Each Other Until There Are No More People Left

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A policeman searches for evidence at the area where body parts were found on November 29, 2013, in Reichenau, eastern Germany. A German police officer has been arrested on suspicion of murdering a man whom he met on an Internet site for cannibalism fetishists, authorities said. The 55-year-old had confessed to slashing the throat of his willing victim and then cutting his body into small pieces and burying them in his garden, police said. Robert Michael/AFP/Getty Images

If food goes scarce, humans could turn to each other for survival. Eventually though, there'd be no flesh left to consume and the human population would soon become extinct—which may happen quicker than you think.

In less than four years, only one human would be left if we all turned into cannibals, according to new research. Undergraduate students studying physics at the University of Leicester in England were interested in exploring the hypothetical situation, so they used a mathematical model to determine the approximate number of days when only a single human would be roaming the Earth.

The team of students calculated the amount of calories an adult male body is worth—about 125,800 calories they conclude—and then estimated that each human would eat a 2,500-calorie diet per day. Using an equation to calculate the scenario, they found that the last human would be left after 1,149 days or a little more than three years.

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The findings should be taken with a grain of salt though, for a number of reasons, including that it was published in an undergraduate research journal and that the method used doesn't take into account a long-list of factors which could affect survival. For example, the authors assume that all food would be shared equally, but if the food wasn't, the human population may thrive much longer than a thousand days or so.

"If instead, a small number of people gathered and stored all of the others, they could potentially last decades," the study authors wrote in their paper.

Additionally, people require a different amount of calories based on factors such as activity level, height and sex. But the authors only account for the recommended daily intake for an adult male. They point out that in order to make their model more accurate, they also must consider the caloric output and intake women and children require, which is typically much lower than grown men.

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While it's unlikely that worldwide cannibalism will be happening anytime soon, a number of recent cases shed light on the nauseating reality that there are some people out there that perhaps, wish it was. Like the Russian "cannibal couple" arrested last September who are believed to have killed, skinned and ate dozens of people. Or, the Florida teen who tried to eat the face off of a man he murdered.