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Cannibalism may actually make a community healthier, but maybe don't try it at home.

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Sources:
https://www.researchgate.net/profile/Laurel_Fox/publication/234150330_Cannibalism_in_Natural_Populations/links/54d3d8fb0cf246475803427f.pdf
https://www.researchgate.net/profile/Laurel_Fox/publication/234150330_Cannibalism_in_Natural_Populations/links/54d3d8fb0cf246475803427f.pdf
http://onlinelibrary.wiley.com/doi/10.1525/aa.1970.72.1.02a00140/full
https://www.nature.com/articles/srep44707
https://ndb.nal.usda.gov/ndb/foods/
http://www.journals.uchicago.edu/doi/full/10.1086/30332
https://www.researchgate.net/profile/Simon_Mead/publication/6986896_Kuru_in_the_21st_century-An_acquired_human_prion_disease_with_very_long_incubation_periods/links/00b4951af99a87c5f0000000.pdf
http://science.sciencemag.org/content/300/5619/640
http://labs.bio.unc.edu/pfennig/LabSite/Publications_files/1998_Anim_Behav.pdf
http://rspb.royalsocietypublishing.org/content/274/1614/1205.long
http://www.journals.uchicago.edu/doi/abs/10.1086/692734
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[♪♩INTRO]

You’d think eating your own kind would be a bad idea.

I mean, it can be hard enough to survive and reproduce without having to worry about members of your own species taking you out, too. But lots of animals are cannibals, from mantises that eat their mates to mice that eat their babies.

So there must be some kind of benefit to it. And since, in the immortal words of The Bloodhound Gang, “we ain’t nothin’ but mammals,” you’d expect human cannibalism to have its upsides, too — even if the idea is a little nauseating. Obviously, there are social and moral factors to consider when it comes to eating people.

But if you strip those away and just focus on the biology, there’s some evidence to suggest that eating human flesh actually has some benefits. For better or worse, cannibalism is a part of our shared history. There’s archaeological evidence that in some societies, human was a part of the original Paleo Diet, accounting for as much as 10% of the protein people ate.

And … human flesh might actually have more nutritional value than other kinds of meat. We have about the same number of calories as other animals our size, so you’d get the same amount of energy from eating a person as you would from eating a small deer. But just like Wagyu beef has much more fat and less protein than a rib eye, human flesh has its own unique profile of proteins, fats, and other nutrients.

The more closely related your meal is to you, the more closely its nutrient profile will match your needs, which would make human meat the most nutritious choice for other humans. Studies in all kinds of animals, from beetles to frogs to fish, have found that carnivores are healthier when they’re fed members of either their own, or closely related species. But there is a major potential downside to eating your own species: disease.

Because when your meal is more closely related to you, it’s a lot more likely to carry diseases you can catch. Probably the best cautionary tale comes from the Fore people of Papua New Guinea. Starting around the 1920s, a disease called kuru started to spread among the Fore.

The name comes from the Fore word for “shaking”, since tremors are one of the symptoms. The sick also walked strangely, slurred their speech, and were prone to emotional instability and bizarre unprovoked laughing fits. The symptoms would get worse and worse, and eventually become fatal.

At the peak of the kuru outbreak, hundreds were dying every year. Researchers have since found that kuru is what’s known as a prion disease — the same type as Mad Cow. Prions are proteins that are folded wrong, which wouldn’t necessarily be a problem, except that they’re hard for our bodies to break down.

And when prions come in contact with properly-folded versions of themselves, they make those proteins fold wrong, too. Misfolded proteins accumulate in the brain, causing holes to form and destroying neurons until the person dies. But prion diseases aren’t contagious — that is, unless you eat something with misfolded proteins in it.

The kuru prions spread because until the 1950s, the Fore practiced mortuary feasting, where they ate parts of their dead loved ones to honor them and mourn their passing. Researchers have found that elderly Fore who survived the kuru epidemic had specific genetic changes that probably made them resistant to prion diseases. We’ve found similar changes in genomes from around the globe, which suggests that prion diseases like kuru—and the cannibalism that spreads them—were common in our evolutionary history.

But prion diseases aren’t the only reasons you’d think eating people would be too risky, and this is where things get weird...er. There are plenty of super contagious diseases that can spread just by touching an infected person — let alone eating them. But, despite the number of cases of human and animal cannibalism, we’ve found fewer examples of it causing disease outbreaks than we’d expect.

And according to a review paper published in The American Naturalist in 2017, there might be a good reason for that: Cannibalism could actually protect people from catching dangerous diseases, because it gets rid of some of the microbes that spread them. Sure, eating someone else exposes you to more pathogens. But at the same time, you’re also protecting the rest of your community from coming into contact with the disease.

A lot of microbes can’t survive things like cooking or the destructive juices in our guts, so you destroy them by eating them. Plus, removing the infected person from the population, both through their death and any action that gets rid of their body, means there’s one less person spreading the disease around. So cannibalism might actually slow the spread of some diseases, or even wipe them out.

You’d still have the prions to worry about, but the net effect of reducing other diseases could make it worth the risk. So, the more we study cannibalism, the more it seems like eating other people’s flesh might not be too bad for our health—our physical health, anyway. That said, I wouldn’t recommend trying it.

It can still be pretty dangerous, and when it comes to preventing diseases, modern medicine is a lot more effective than eating people. Plus, there are plenty of other ways to practice a healthy lifestyle, and it helps to have a variety of resources for staying in shape, both mentally and physically. Skillshare is an online learning community with over 1600 classes in health and wellness, from nutrition to mindfulness and more.

A lot of these classes talk about how exercise and an active lifestyle are key for success in creative careers. In this lesson of 7 Simple Habits of Highly Creative People, habit #5 is literally “Exercise,” and this class about writing productivity emphasizes the importance of taking a break from the desk to stretch your legs on a walk. And if you’ve by some miracle already nailed health and wellness, you still have something to learn from Skillshare’s 17,000-plus classes in design, photo, and more.

Premium Membership gives you unlimited access so you can improve your skills, unlock new opportunities, and do the work you love. The first 500 SciShow viewers to use the promo link in the description will support the production of this channel and get a free 2 month trial of Skillshare. Thanks for the support and thanks for watching.

[♪♩OUTRO]