12 replies to this topic

[Coca]

So one random afternoon I decide to read Tokyo Ghoul, and while the story is certainly engaging enough, the scientist in me is bothered by certain "peculiarities" in regards to ghoul physiology. But before we get into ghouls, let's talk about humans for a bit.

What separates human flesh from any other flesh? What is the difference between a human and any other animal? The answer is not philosophical in any way. It is very simple and concrete; You are what you eat. The only thing that really separates man from animals is our diet. All your mass is basically water, air, and whatever you've consumed throughout your entire life. Our DNA may be different, but DNA itself is all the same. It's all protein. At a cellular level our flesh is virtually identical to that of any other mammal.

So why do we taste different? Why do different animals taste different from each other? There are many reasons for this.

Numerous factors contribute to the taste of meat, and is why even meat from different areas of the same animal will taste different. I've copied the longer explanation below:

Spoiler

Why do different meats from different animals taste differently? From a biochemical perspective?

If all meat is made of the same organic material such as proteins, vitamins and minerals then why would it taste differently

Update : So far, Andi's explanation is the best because of the specific details he includes in his explanation. In summary, even though different foods including meat may contain the same organic compounds, it is the ratio of compounds that is unique to differnet cuts of meat or other foods that alter the taste. Even in meats that come from the same animals may have different tastes simply because of the proportion of fat and other compounds that could be attributed to the lifestyle of the animal when it was alive.

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AndiGravity answered 3 years ago


The short answer is "because their biochemical make-up is different".

The long answer is "because their biochemical make-up is different," followed by a long list of things that boil down to "because their biochemical make-up is different".

First, there's the fact meats contain a different spectrum of vitamins and minerals, and those usually have a unique taste to us. Vitamin C tastes sour. Zinc, iron, copper, manganese, etc taste metallic. Calcium tastes dusty, oxalate tastes dry, niacin tastes like... well, to quote Ralph Wiggum "it tastes like burning," and so on. The presence and amount of each micmicro-nutrient in the meat is going to make each meat taste subtly different.

The second thing that's going to influence the flavor of meat is the relative presence of myoglobin. Myoglobin tends to be one of the underlying causes of what you might describe as a gamy, or bloody, flavor in meat. Different meats contain different amounts of myoglobin, even in the same animal. This is very pronounced in poultry, such as chicken and turkeys. The muscles that get exercised contain more myoglobin, resulting in "dark meat". The muscles that remain unexercised contain less of it, resulting in "white meat". There are distinct flavor differences between the two. The same is true of red meats, such as beef and pork (which doesn't contain nearly as much as beef or buffalo, but still contains far too much to be considered a white meat).

The same rule of "red" vs. "white" also holds true for fish. If you've ever eaten sushi, you know that tuna tends to have a much stronger flavor than sushi made from white meat fish (though if it tastes rotten or coppery, it's gone south on you... truly fresh fish should neither smell nor taste foul). This is even true of cooked fish. Get a white meat fish such as cod or halibut and cook it, and then taste it along side some cooked tuna and see if you can't still distinguish a much stronger, more metallic flavor in the meat of the tuna (even though it has turned pale).

Third, there are also varying levels of fat contained in the meat of each different animal, which will influence the flavor and texture of the meat (remember, just like meat itself, fat stores different levels of vitamins, in this case A,D,E and K).

Next, different meats are going to have different levels of connective tissue in them. Some, such as elastin, are going to be unpleasant. Cooking them does nothing good for them. Other connective tissues can be more successfully manipulated to enhance the flavor of the meat. The most notable example is in the preparation of rib meat on the bone. The "low and slow" approach is meant to allow the collagen in the bones to liquefy into gelatin and infuse the meat. This will both alter the taste of the meat (go to the baking section of the grocery store and buy some unflavored gelatin, and taste it if you want to find out what it tastes like on its own, because it has a distinct, if easily masked, flavor) as well as its texture, resulting in that sought-after silky mouth feel. On the other hand, tenderloin contains virtually none, which makes it impossible to get the same bold flavor and texture out of it, no matter how you cook it.

So, that's part of why different meats taste differently.

It isn't just that meat from different animals taste differently, but the age of the animal makes a difference (the chicken you buy in the grocery store tastes markedly different than the rooster you would use for coq au vin, lamb tastes different than mutton, etc), where on the body you take the cut of meat from makes a difference, how much exercise the animal gets makes a difference, even what its diet was (because that will influence the final ratio of macro and micrmicro-nutrients in the meat... corn-fed vs. grass-fed beef being a prime example).

Source:
Jonathan-- Like I said. Long list of things that all boil down to "because their biochemical make-up is different".

Incidentally, what does human taste like? This video provides the best answer I've heard to date. But again, a grass-fed cow will taste differently from a corn-fed cow. Whatever any human will taste like will depend greatly on whatever he has been eating most of the time. As the old saying goes; "Garbage in, garbage out". I suspect that vegetarians will taste better, but there's only one way to confirm that.

Apparently, the only naturally occurring substance that a human can subsist on exclusively, for the rest of his life, without succumbing to some kind of deficiency, is human breast milk. Of course it's not feasible to harvest human breast milk in any significant quantity, and even if you could there are several issues, not least of which is that the taste would vary greatly, again, depending on the diet of the human in question. But we've come a long way in developing intravenous therapy and parenteral nutrition (food directly into bloodstream), and now there is a convenient, nutritionally complete alternative to traditional food, called Soylent. It's quite affordable, and you technically never have to eat again, because Soylent contains everything you need.
The point of all this is that human nutrition is not mysterious or overly complicated. It can be broken down to its elements and optimized for maximum efficiency.

Now, about those ghouls. The two main things are:
1.) Everything tastes nasty. Except people. And also coffee (???).
2.) Even if they could swallow other food, it doesn't sit well and makes them sick. The rejection seems similar to an allergic reaction or intolerance... to anything that's not human meat. Or coffee. Humans are their exclusive diet.

(Perhaps ghouls could also eat other ghouls, (or even themselves like with the Gourmet) but that doesn't seem like a long-term solution.)

Based on what we know about meat in general, any logical person can see some problems with this situation. Forget the coffee. How is it possible that only human meat tastes good when there is (reasonably) similar tasting meat in other animals? Sure nothing else would taste quite like human meat would, because no other animal has a diet quite like humans, but even humans have very different diets from other humans and yet the ghouls don't seem to discriminate in the slightest. Human is human, it's either good or superb. I have yet to see a ghoul say "Ugh this human tastes bad". I am assuming ghouls have been around for a while, and have actually tried eating other animals raw like humans, and it somehow didn't work out. It simply has to be human. Since we already established that there isn't anything differentiating human meat from say, veal or pork, on a cellular level, there shouldn't be any reason a ghoul's body couldn't accept other animal meats even if they (somehow) didn't like the taste.

But no. The author has written it so that human meat, and only human meat, is nutritional and life sustaining, while virtually identical meat is poison. Human meat = OMFGMOUTHGASM. Other meat = WTFSOGROSSOMGIAMGONNADIE
Are we really expected to just believe this? That this somehow makes some kind of logical sense? I eagerly await the hand-wavy explanation the author has in store for us, if he doesn't completely side-step this issue.

There also shouldn't be anything stopping them from making a synthetic mixture composed of the base ingredients of human meat, a soylent for ghouls. Though I suppose there aren't many ghoul scientists around working on this.

But let's go back to breast milk for a sec. We know that human breast milk is nutritionally complete for humans and also contains useful antibodies for a superior immune system. But what about ghouls? Do ghouls breastfeed? We know that ghoul and human physiology is extremely compatible since it was shown to be possible to transplant a ghoul organ into a human without any rejection from the host immune system. Interspecies transplants, or xenotransplantations, have been researched extensively over the years, but there has never been a successful trial involving transplanting an animal organ into a human. Chimpanzees would be our best bet in terms of organ compatibility but since chimpanzees are endangered, no medical trials have been conducted using organs harvested from chimpanzees. The few attempts at transplanting animal organs in the past have all ended in death. So if ghouls and humans are so similar biologically, it wouldn't be such a stretch to assume they gestate and nurse in a similar manner. Ghoul breast milk would technically provide all that a ghoul baby would need. I imagine ghoul babies to be much like human babies at birth. Eating solid foods straight out of the womb seems highly improbable. Drinking blood would not help either because blood does not contain nutrients in an ingestible form. It must be injected directly. Assuming ghoul babies also have tough skin, I can't see how constantly injecting blood into a baby would be feasible. So aside from solid food, breastfeeding seems to be the most likely scenario. If they somehow synthesized ghoul breast milk, this could be a breakthrough solution.

But OK. Ghouls are super, extra, special, and they MUST have actual human meat to survive. A possible solution could be lab grown meat. Just last year, they served a lab grown hamburger to a few critics and it worked out pretty well. They grew the meat using muscle stem cells from cows. There is technically nothing preventing this technique from working with human stem cells. Any meat grown from human stem cells would be actual human meat. Not fake meat, real meat. Just without most of the fat, not that I think any of the ghouls would care about the lack of fat. They really aren't picky when it comes to humans, lean or big.

I realize the author is not writing a treatise on fictional ghoul anatomy (even though he did whip out the ole unabridged skeletal diagram for one of the recent chapters) I find certain things too big to simply sweep under the rug, especially when they underpin the basis for the conflict between ghouls and humans, that being ghouls must eat humans and only humans.
 

[LovelyLuvLuv]

Interesting analysis. I considered this and in the end, i don't want to drink soylent everyday. If they made an artificial human meat that tasted as good as real human meat, i'd probably go for it as a ghoul. Although, it still won't change the fact that humans are still meat to me and sometimes i may want my steak cut instead of ground/lab grown beef.

[Coralira]

I agree that they could do something like that for a ghoul but in the current situation in the manga it doesn't seem that there's anyone kind enough to do that. Most of them think of ghouls as monsters, simple as that. This story could be about changing that though.
I actually wouldn't be surprised if this kind of solution comes up later, then they could give ghouls that injection that makes their strength human. I imagine some ghouls like being ghouls though.

[Rak_Wrath]

I agree that they could do something like that for a ghoul but in the current situation in the manga it doesn't seem that there's anyone kind enough to do that. Most of them think of ghouls as monsters, simple as that. This story could be about changing that though.
I actually wouldn't be surprised if this kind of solution comes up later, then they could give ghouls that injection that makes their strength human. I imagine some ghouls like being ghouls though.

I'd imagine most ghouls are pretty far-gone in terms of the morality of eating people. Some might actually conform to the system because they don't want to be hunted, others might conform in name and keep eating people. There'd be a range of solutions on that end, from camera-wearing ghouls to more complex biological solutions (perhaps identifying biomarkers involved in ghouls eating humans vs the human substitute).

[nallekarkki]

 

 

I have yet to see a ghoul say "Ugh this human tastes bad"

 

I actually remember something like that from first chapters... Touka-chan said in the beginning that old mans meat doesn't taste so good... And several ghouls have preferences about their pick of human meat (age or texture of the meat) like Rize-san and Godfather. Not to mention that there are humans like Kaneki, that just smell particularly delicious to ghouls... More like most ghouls don't have the luxury to be so picky most of the time... They are relentlessly hunted and killed by CCG when exposed. 

 

I think the main reason why ghouls can eat only human (and ghoul) meat are the fictional rc-cells... Found this from wiki...

 

"Rc cells are certain cells that exist only in the story of Tokyo Ghoul. They exist in both humans and ghouls... Rc cells are the nutrients ghouls need to ingest."

 

This doesn't explain the coffee....

 

And the reason why ghouls haven't been able to make synthetic food for theme selves is the problem of resources... They would need to go schools (to tight rope like Touka-chan) to gain knowledge and to be able to work in society and if I understood correctly, there are ghouls who can't even write...

 

And I think also that most of the ghoul research are done by CCG...  

[Coca]

I suppose RC cells are the new midi-chlorians. Very popular those little guys. The higher your RC count, the more likely you are to be a Jedi ghoul. That makes sense but still doesn't explain why only humans have RC cells, though that would conveniently explain why only humans taste good. Ghouls can't produce RC cells on their own and ghoul children would only have the RC cells from their mothers until they can feed on their own.

 

I also assume younger ghouls are just as picky about their food as younger humans (even not-so-young humans are picky at times) but when they don't like a certain kind of meat I'm guessing they mean it like a really low quality steak, as opposed to "inedible" as they see everything else (except for coffee--which still doesn't make the slightest bit of sense).

 

Ghoul origins would be fascinating as we still don't know if they're a mutation on humans or a different subspecies of humans separate from homo sapiens, like the Denisovans. The other "One-eye" ghoul who's supposedly a natural hybrid rather than the result of a transplant like Kaneki would indicate that ghouls and humans are mate-compatible, but with many risks. If this One-eye is fertile and he (or possibly she) is indeed a true hybrid, this would confirm that ghouls are a subspecies of human, like dogs and wolves. If One-eye is infertile, but is still a true hybrid, this would indicate two separate species that are mate-compatible, like horses and donkeys.

 

They mention complications with bringing a half-breed to term, but I can see it happening in two ways:

 

1.) If the mother is a human, turning cannibal may provide enough nutrients for the baby. Or some very special IV drips.

 

2.) If the mother is a ghoul, regular doses of RC suppressant may prevent the mother's body from absorbing the baby.

 

Either way it would make sense why hybrids are practically unheard of. One requires a very "open-minded" mother, while the other requires someone with knowledge of ghoul physiology and access to special substances, like Dr. Kanou.

[nallekarkki]

the more likely you are to be a Jedi ghoul

 

lol 

 

Then again... coffee is a drug.... So maybe rc cells are actually more like stimulants... Think about the reactions, when Kaneki actually ate human flesh and he said that he refuses to give in the pleasure... So.... Ghouls are highly addicted junkies and start to binge eating like Rize-san... But then again why kagune tastes bad? Is it some kind of defense mechanism... that ghouls don't eat their own kind?  

 

This brings me mind the chapter where while lunching Mado gave Amon the suspicious looking little package and said... that CCG had developed what ever it was... that humans could fight with ghouls better: it heightened their reflexes. 

 

Maybe the chemical composure of coffee is close rc cells...and that is why ghouls are okay with coffee? Is this even possible? I have little or no knowledge of medical science... just got caught by interesting topic. But why coffee.... why not tea or cola or Red Bull energy drink.

 

I also assume younger ghouls are just as picky about their food as younger humans

 

I have never seen that a hungry predator will complain about their food... The ghoul hunger is literary hell...  

 

Then again... my cat is very picky, he eats only premium and can withheld from eating for days if food is not his liking. XD But then again.... maybe he isn't qualified as a true predator. And he is absolutely by no means... hungry predator. 

Edited by nallekarkki, 12 July 2014 - 09:41 AM.

[Overweight Otter]

Didn't dr. Ogura (chapter 2) say that ghouls have some enzyme that makes them unable to digest non-human nutrients? Is that a sufficient explanation? And there was also the stuff about the structure of their tongues affecting their sense of taste.

 

Just saying, because the author seems to have explained a ghoul's diet this way.

 

Edit: Ok so Ogura is apparently not a trustworthy ghoul expert (chapter 93), so there's no need to believe his words.  

Edited by Overweight Otter, 02 August 2014 - 01:24 PM.

[Iron_Maw]

lol 

 

Then again... coffee is a drug.... So maybe rc cells are actually more like stimulants... Think about the reactions, when Kaneki actually ate human flesh and he said that he refuses to give in the pleasure... So.... Ghouls are highly addicted junkies and start to binge eating like Rize-san... But then again why kagune tastes bad? Is it some kind of defense mechanism... that ghouls don't eat their own kind? 

 

I don't remember anything being said about Kagune tasting bad, it's ghoul flesh that does because according Kaneki it's coarse compared to human flesh.

[Tony911]

I asked myself the same question. Thanks for the detailed post, but this can all be resolved with three words: fiction is fiction. It was done to add conflict to the story. I'm sure the mangaka thought of this while he was carefully planning out the story.

 

If ghouls could be happily sustained by eating a pork chop then they would all be holding hands.

[RAGE]

I don't know if this helps but when I read that they can't eat anything non-human, i thought of the terms Dysgeusia and Dysosmia.

Dysgeusia is the distortion in the perception of taste. It can be that a person tastes a different quality of a certain item, or there is a perception of taste when there is actually nothing ingested. E.g.: Tasting an apple as salty. Causes of this can be: drugs, radiation, heavy metal intoxication, certain diseases etc. There are a lot of causes of this, including distorted taste buds, which was also mentioned in the manga.

Dysosmia is the distortion of the perception of smell. Its like Dysgeusia but with smell. Like, dysgeusia there are also a lot of conditions that can cause this. 

Anyway, these 2 terms helped me in getting over the "ghouls can only eat human meat" part. And it also explains the coffee part (they taste coffee "normally"). 

Hope this helps.
 

Edited by RAGE, 23 July 2014 - 06:28 PM.

[Inumori]

In regards to taste and nutrition:

 

In large part, the perceived taste of a meal is registered in the brain relative to the value an organism's body places on the nutrition therein. Understand that organs and nervous tissue are not self-aware and do not recognize the availability of food in modern society. Taste buds on the various tongues of the various lifeforms tasting with them are lain out differently and often composed differently as well, and this can combine with the massive variety of tastes and materials out there for curious effect. For example; a cat will lick a plastic bag because the odd synthetic structure is misrepresented as something positive by their tongues, that is to say, their chemo-reception does not know how to account log this material and offers a sort of "false positive". This could readily explain the coffee tolerance in the ghouls.

 

Additionally, if your body is incapable of processing a type of food it will often develop changes to taste and smell to ward its feeder away from such things. Using myself as an example, I can't eat fish. Even though I used to actually like the taste, eating it would always make me sick and now the smell and taste are so intolerable it's hard to even approach it. This is not an allergy. This is because a lack of the enzymes used to break down fish meat leaves me unable to process nutrition from it, which causes the body to recognize it as a foreign contaminant.

 

So you see it's not about the similarities between different meats and how one is too close to the other for a noticeable difference. Even between land animals there are large differences in how the body must process the material. Pork, beef, the various game meats and poultry, each of these tissues retain their nutrients in different ways. It's an absolute marvel of evolution and a large part of humanity's place at the top of the food chain that we can eat damn near everything. That's actually really very uncommon. A ghoul likely loses the ability to produce the enzymes used to process most foods, leaving them with only the capacity to eat humans and each other.

 

As for solutions? Given the above, enzyme supplements would theoretically allow the processing of other meats whilst infusions could provide the needed RC cells if they don't exist outside of humans and ghouls. Lab processing and the like could also potentially solve that problem. The real issue is society. It's implied that most ghouls aren't able to integrate well enough to become researchers and doctors, and research into these fields is expensive beyond the means of hunted, low-profile individuals. Past that humanity as a whole hates ghouls. Individuals can rise above this, sure, but it's already been revealed that ghoul tolerance is actually highly illegal in this world (or at least this world's Japan). A lot of money and jobs go into hunting ghouls down too, and so the issue of what to do with the massive organizations and funding should mutual peace arise. Not many people are likely willing to let go of that. Then there's the political implications, the struggle of giving rights to ghouls, tensions and aggressions from victims on either side and the narrow-minded, possible civil war, definite riots, violent escalations. Even if the end result is better than it is now, how many people are willing to risk all that for a change that doesn't even help them? Can it happen? Sure, especially given that this is a story and that makes for excitement, but it sure as hell won't go cleanly if it does.

[DorkingtonPugsly]

I wonder if ghouls can eat other primates, they're the closest mammals to humans so maybe some Ape Barbecue would taste okay? Easier to stomach than other animals? Can't really obtain primate meat that easily so idk...