How Many Calories Are In A Human

How Many Calories Are In A Human

If you were to eat, say, another human being, how many calories would you be taking in? That’s a valid question not only for health-conscious people, but for anthropologists, too. You see, our human ancestors were cannibals — but we don’t really know why. Did they kill and eat each other like they would a mammoth or a wholly rhino — for the meat? Or were they practicing some sort of religious ritual? To answer that question, James Cole, a senior lecturer in archaeology at the University of Brighton, looked into the nutritional value of a human being and then compared it to that of other animals our ancestors dined on. He found that eating a man provides fewer calories than gobbling down a mammoth, bison, or red deer. And that suggests that our ancestors ate each other not for nutrition but for some other purpose — maybe as a form of funerary or cultural ritual. The findings were published today in the journal Scientific Reports. Was it some sort of religious ritual?

Caloric Value of a Human Being

To calculate the calories of a human being, Cole looked at several studies done in the 1940s and ‘50s that analyzed the protein and fat content of different parts of the human body. From that information, he could calculate how many calories you get from a one-pound heart (650), a four-pound liver (2,569), and three pounds of nerve tissue (2,001). After combining all organs together, you can basically slap a nutritional label on a human corpse that reads: 125,822 calories. At least, within the constraints of those 1940s and ‘50s studies. (They analyzed a total of four men, ranging from 35 to 60 years old, and weighing an average of 145 pounds, so Cole’s caloric count only applies to male Homo sapiens with those parameters.)

Comparison with Other Animals

Cole then wanted to compare our nutritional value to that of other animals known to be eaten by early humans. Again, he pulled from the published literature, and calculated how many calories you could get from the muscle mass of 20 ancient animals. (No information for internal organs exists, Cole says.) He found that the muscles of a mammoth would provide 3,600,000 calories, woolly rhinos 1,260,000 calories, and red deer 163,680 calories. In comparison, a man’s muscles can get you only 32,376 calories. “We just aren’t that nutritionally viable,” Cole says.

Purpose of Cannibalism

So if eating a man isn’t that nutritious, why in the world would our ancestors spend time and resources to hunt other hominins that are just as smart just to get dinner? Cannibalism must have had another purpose, Cole says, possibly one connected to warfare or religion. Other researchers think those are valid conclusions. “There can be a cultural explanation for all of these episodes of cannibalism,” Rougier says. But that’s not a completely new conclusion, she says. For years now, we’ve gotten more and more evidence that early humans like the Neanderthals were actually quite complex. So it’s totally plausible that they ate human flesh for more than just gobbling down some juicy meat.

Complex Attitude Towards Cannibalism

“We know that modern humans have a range of complex motivations for cannibalism that extend from ritual, aggressive, and survival to dietary reasons,” Cole writes in the study. “Why then would a hominin species such as the Neanderthals, who seem to have had varying attitudes to the burial and treatment of their dead, not have an equally complex attitude towards cannibalism?”

Archaeological Evidence

This conclusion falls in line with an existing school of thought, which suggests, based on archaeological evidence, that cannibalistic episodes were motivated by social, cultural, and spiritual factors. At Gough’s Cave in England, for example, archaeologists found a large cache of human bones that showed evidence of defleshing and chewing. The people who gnawed on those bones probably didn’t do so out of hunger; there were plenty of animal remains found within the cave, and some of the human bones appeared to have been marked with ritualistic etchings.

Survival and Opportunistic Feeding

But Cole’s caloric comparisons cannot discount the possibility that humans used one another to supplement their diets. Ancient humans were likely opportunistic feeders, as Cole acknowledges in his study. Perhaps they turned to cannibalism when someone passed away, as an easy way to fill their bellies. Perhaps they resorted to eating one another when other food sources were scarce.


Ultimately, every cannibalistic episode happened under different circumstances, Cole writes in his study, and no one can say for sure why our ancestors opted for the occasional human smorgasbord. But Cole’s findings lend further credence to the notion that some ancient cannibals were acting out of choice, not desperation.


1. What motivated ancient cannibals to eat human flesh?

Ancient cannibals were likely motivated by social, cultural, and spiritual factors rather than pure nutrition. The act of cannibalism may have been connected to warfare, religion, or ritualistic practices.

2. How many calories are there in a human body?

According to the study, the human body contains about 125,822 calories, based on the protein and fat content of different body parts.

3. Why did our early ancestors eat one another?

Some scientists speculate that ancient cannibals had reasons other than nutrition for consuming human flesh, such as social and cultural motivations. The act of cannibalism may have been driven by complex attitudes towards burial and treatment of the dead.

4. What does archaeological evidence suggest about cannibalistic episodes?

Archaeological evidence indicates that cannibalistic episodes were motivated by social, cultural, and spiritual factors. For example, evidence of defleshing and chewing on human bones in certain caves suggests ritualistic practices rather than hunger.

5. Were ancient humans opportunistic feeders?

Yes, the study acknowledges that ancient humans were likely opportunistic feeders and may have resorted to cannibalism as a means of supplementing their diets, especially when other food sources were scarce.

6. What does the study conclude about ancient cannibals?

The study suggests that some ancient cannibals were acting out of choice, not desperation, indicating that cannibalistic episodes were likely driven by social, cultural, and spiritual motivations rather than pure nutritional necessity.

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