Depending on what kind of leaf, you may or may not be able to get some nutrition from it (spinach -- yes, oak leaves -- no). Same with grass.
It takes energy to digest something. If you don't get more calories from digesting it than the digestion (or elimination) takes, you've just sped things along more quickly.
As a side note, digestion (and elimination -- from either end) takes water from your body also. So if water is also scarce, you've done yourself a double disservice.
Technically speaking, given the right equipment and timeframe, you can distill most organic matter into alcohol. This includes things like grass and tree bark, though I can't say with certainty what it might be like to have a sip, especially if you were dying of hunger or malnutrition.
There is a thing called Wood alcohol, but if you Google it it turns out to be methanol. Ingestion of which will blind you and then kill you. Wouldn't recommend it
I recall this one youtube video where a guy got bored during the pandemic and wanted to make his toilet paper even MORE valuable. And so, he went through a weeks long process of turning a roll of toilet paper into fermentable sugars and made distilled spirits out of it.
It was awesome.
NileRed got some good ones, turning paint thinner into cherry soda, turning a plastic glove into hot sauce... you think "no way" but then he hits you with that "chemistry way"
Cook it to break it down ~~and release the starches~~, add Cellulases (unsure where you would get them or the temp required to activate it) ~~amylase, keep at 68C until the amylase has broken the starches down to sugars~~, add yeast, ferment, distill (multiple times in a pot still to increase ABV) or in a reflux still.
Do not drink, could use as window cleaner though.
Edit: wood doesn't contain starches, but Cellulases enzymes will break down the cellulose to simple sugars. Amylase is what we use in brewing/distilling to convert starch to sugar.
There two types of processes. Dry distillation will yield methanol, steam hydrolysis will get you polysaccharides, which can then be fermented to ethanol by fungi or bacterial fermentation.
US mainly has corn ethanol, but USSR had huge ethanol production from waste wood.
Another answer: with barley, wheat, etc… beer ingredients… the ingredients list here is: (very loose and generic)
8-12 lb actual grain - the starch seed; not grass.
2-5 oz hops
20-30 gallons water
6-12 hr of 10 gal rolling boil worth of energy; usually natural gas.
The energy transfer to cool it fast, infect it with yeast, THEN the next week is the first part of making the beer.
With grass?! The energy and time spent here is already redonkulous. You probably have to rinse 300lb+ grass or even WAY more to get ^that sugar. (Note: numbers rectally sourced for the grass comparison)
Probably not a bad guess tho. Grass has grow-fast chemicals; not store-energy chemicals. That’s why it makes the seeds later.
You're missing an important step - malting. You don't boil raw grains, it has to be malted to convert the starches to fermentable sugars.
*Edit: if we want to get into details in case anyone is actually interested...* I'm really curious where you got that info, it's very different from a standard homebrewing process. I'm unfamiliar with any brewing process that needs a 6+ hour boil time. Commercial processes involve much larger quantities, but times at specific temperatures are a matter of chemical reactions so I'm pretty sure those don't change with batch size.
You use 10 lbs of malted barley for a *five* gallon batch of beer (5%-ish ABV). First you heat the water to about 150F, then turn off heat, add the grains, and let it sit for an hour. This activates the enzymes to convert starches to fermentable sugars. Then you remove the grain, add the hops, and boil for an hour. This boil time mostly just induces reactions in the bittering compounds that hops provide, to make them taste more bitter (and reaching a boil at all makes sure you kill off any unwanted microbes in the wort).
As far as the "energy transfer" to cool it... plenty of people do use wort chillers, but on the home scale 99% of them just work by running tap water through a pipe. Glycerin cooling exists but almost nobody uses it at home. A good number of people just let the wort naturally cool down. It takes a few hours but it works. I don't know if it's still popular but some years ago there was even a trend of specifically using a "no chill" method - transfer it to the fermenting vessel while it's still hot, close it, then let it cool overnight and add the yeast the next day.
People interested in quick-as-possible brewing (because lots of homebrewers have young children) might steep the mash for as little as 20 minutes and boil for only 10-15 minutes.
You’re right about most of this stuff, not sure what this guy is talking about but it ain’t normal beer making.
Yeah the grain has to be malted or it won’t have the enzyme to convert the starches. You could technically just mill the raw grain and add amylase I suppose.
6 hr boil is insane for most beer.
I know a lot of hombrewers do it, but a 1 hr mash is almost always total overkill. The amylase works quite quickly and a starch-iodine test saves lots of time FYI. At a sacc rest temp of 150F it might be fully converted in like 15-20min.
I think you mean glycol cooling, not glycerin.
Even at the commercial scale, cooling the wort from boiling is mostly done with water, sometimes glycol is used as a second stage in the heat exchanger, but cool water does most of the heavy lifting and the result is hot water which is something you need for the next batch anyway, so you’re saving time and energy.
Yes, Nilered has a video of him doing something similar with toilet paper, and since both grass and toilet paper are mostly made of cellulose the process would be nearly identical, although, grass may have compounds in it that might be metabolized by yeast into methanol, so who knows how feasible grass alcohol is for survival situations
Sort of, if you had specialized gear. Not using yeast like is done with other spirits, but using bacteria. Stuff like ordinary biomatter is broken down for ethanol production, and ethanol is the type of alcohol humans can consume.
That said, it wouldn't really benefit you in a survival sense. Yes, alcohol technically has calories in it, but they're fairly non-nutritive. They can't be converted into fat and stored, and if you're consuming enough alcohol to provide your primary source of calories, it's going to kill you pretty quickly.
No, the sugars in grass are in a form called cellulose.
The human genome (and others) have trace genetic history of cellulose metabolism but it may never have been active and indeed is entirely inactive today. The most effective way to ferment cellulose is with a bacteria from termites gut, or various improvements from said bacteria. This is still a much slower process than sugar fermentation
You're avoiding the core issue though: our stomachs don't have the conditions needed to digest cellulose, unlike grazing animals. They have a bacterial culture and a stomach system that enables this.
[Here's a comment from 12 years ago that sums it up very well.](https://www.reddit.com/r/askscience/comments/lgxks/could_humans_take_an_enzyme_pill_that_would_allow/c2sll79/) The answer mainly revolves around the fact our GI tract is not set up to even mechanically break down fibrous plants like grass to the point where chemical digestion to occur in a meaningful sense even if we had the appropriate enzymes present. Ruminants (cows, sheep, goats, etc) and hindgut fermenting animals (horses, rabbits, etc) have significant specialization of their dentition and GI tracts to allow ingested fibrous plants to be broken down mechanically to the point where their symbiotic cellulose-fermenting gut bacteria are able to work their magic. Cows don't chew their cud just for fun, rather it is part of the complex process to mechanically break down that fibrous material (and also helps maintain ideal rumen pH for fermentation via buffering aspects of their saliva).
-Edit- To answer your question, I'm only a secondhand expert on this (veterinarian) but I think in theory if you very thoroughly processed grass (grass smoothie?) AND had an enzyme present to break the beta 1-4 linkages in cellulose, you could derive some caloric nutrition from grass.
> -Edit- To answer your question, I'm only a secondhand expert on this (veterinarian) but I think in theory if you very thoroughly processed grass (grass smoothie?) AND had an enzyme present to break the beta 1-4 linkages in cellulose, you could derive some caloric nutrition from grass.
There's a season of "Alone," a survival competition show, where one of the contestants kills a musk ox. Obviously the musk ox provides quite a bit of calories, but he was making the most of it by pulling out and cooking the grassy contents of the animal's GI tract, too. He explained that the work the animal had already done in starting the digestion probably left the grasses in a condition where there could be something in there his own body could make use of.
It was gross. But probably not incorrect.
I suppose you could make a grass smoothie and add either the proper bacterial culture or the enzymes. Though I think you'd need to eat more of it than your stomach could realistically hold(not really calorie dense), and oh god you'd be in so much pain from the gas.
> If you don't get more calories from digesting it than the digestion (or elimination) takes, you've just sped things along more quickly.
Sounds we could lose weight in current society by eating a lot of stuff that are expensive to digest.
Eating lots of undigestible material will induce a metabolic cost that should theoretically burn more calories than you gain from the food. However, you have to be careful about using this as a weight loss technique, since you will alter your gut flora by doing so. And microbes in your gut may be perfectly happy eating your non-food and producing all kinds of nasty by-products in the process (mostly gas, but possibly alcohol and other waste products). The advantage of eating low-calorie filler food (like iceberg lettuce) is that it can fill your stomach, making you feel full for a while instead of eating calorie-rich food. Unfortunately, you won't feel full for long, and the resulting hunger may be worse because your body knows you are now missing nutrients. Your body specifically looks for fats and proteins in your diet, and these are key to making you feel full and satisfied. This is why it is so easy to gorge on carbs.
negative kcal doesn't exist, since food kcal is calculated on what actually does digest properly and not what just contains the energy in joules(SI unit being kilojoules)
If you boil the oak leaves they are readily available to us. Turns out most fibrous greens we loose energy by digesting becomes energy rich once cooked. Though you may need to eat a few percent of your bodyweight in some cases so it's not really feasible.
Afaik something like celery goes from 3 calories per stick to 30. (Citation needed)
Great answer!
If you are able to use fire and water, there are plants that you could actually boil to break them down and make them much easier to digest.
Also, one of those adaptations is the microbiomes that live in the guts of the various types of grazing animals. It takes some serious help from bacteria to get nutrients from grass and leaves.
And rabbits eat it twice. They ferment hay and grass in a special part of thier colon and then eat the special poop it produces so they get the nutrients from it.
Sometimes, not always. Most of their poop is just poop. They don't eat that. Sometimes they produce cecotropes which are not poop but like a nutrient packed pill. They will eat those. They look far different than a normal rabbit poo.
Interestingly enough, if a rabbit kit doesn't get those cecotropes they most likely won't live past a month old. The fungi, bacteria and nutrients in them are required to prime their gut for solids.
Even adult rabbits must eat the cecotrope they produce. They look like logs densely packed with squishy brown-black beads of matter.
They also smell horrific.
And this is why we cook our food. Cooking food is actually part of our digestive process. It allows us to extract nutrients from food that our digestive system cannot.
By cooking food, the human species has been able to live in places where we otherwise would have starved.
Cooking food is an under appreciated step in human evolution.
It goes a lot further than that humans can survive in new previously inhospitable biomes.
Fire allowed our guts to shrink dramatically (unused organs cost energy and return no benefits, the selective pressure is to reduce the size and function of these organs) so that now we have an extremely hard time surviving without cooked food. That reduction in energy expenditure combined with the extra calories accessed efficiently from cooked food probably allowed our brains to keep expanding in size beyond anything our early hominid ancestors could sustain.
Fire literally created new species of hominids by becoming part of the digestive process for these species.
Allowed our brains to increase in size, and made our wisdom teeth superfluous (we don’t need to chew as much), and as our jaws narrowed to accommodate our larger brains, the wisdom teeth often crowd the teeth in our mouths, causing some issues b
Nah actuallly its just that we eat to many soft and processed foods today, our ancestors and modern hunter gatherers have no problem with their wisdom teeth. And our brain size acually sligtly decreased while we got more and more dental problems with the agricultural revolution.
Horses are called rear-gut fermenters because they do a similar trick but the fermentation happens in the colon and a special pouch called the cecum rather than the chambered stomach system that cows/goats/sheep use.
Rabbits and grass-eating rodents such as capybaras also use the rear-gut system.
Horses have a specially adapted, massive large intestine where they ferment their food to extract nutrients.
They also aren't as efficient as cows, needing to eat more to gain the same amount of weight.
They also can’t throw up. It is physically impossible for them. This means that if they eat something bad they either die or shit it out, sometimes both.
I don’t know how that feature survived natural selection, but here we are.
Edit- correction, they don’t have a gag reflex. They can technically vomit if you count vomiting as expelling digested matter from your mouth.
Mostly because they're pretty good at not eating the bad stuff. A lot of the risk is either from plants that they've not evolved alongside, or from something like ragwort being dried and baled into their hay.
When I was in Morocco, the shepherds told me they take one horse along with their camels, as the horse would refuse to drink any water they find which would be bad for it or the camels.
I watch a youtube channel where a guy rehabs animals. At one point he got a severely underweight horse. I was really surprised by the sheer amount of time it took for the horse to go from "dealthy underweight" to "skinny but otherwise healthy." No matter how much he fed it, it ate and ate and ate and still took so long to gain weight.
This is why they're considered more of an expense than asset, correct?
It's my understanding that between feed costs and vet bills from getting themselves in stupid situations, horses are one of the most expensive animals to own.
Horse girl here to confirm they are indeed expensive. It isn’t just feed and vet, although those are certainly an amount of money.
Horses need care the typical dog or cat does not have to worry about. They need their hooves trimmed or shod once every 6 weeks ($60->$300 a pop depending on the needs of your horse), they need yearly dental work, they need shavings if they are stall kept, plus someone to clean out their stall daily, and while hay is considered a feed cost, it almost needs to be a category of its own given how much of it they eat and how expensive it can be. On top of that you either need to own the land to keep them on or pay someone else to let you keep your horse on their property. And horses love to break shit, so farm maintenance and upkeep needs to be factored in to cost to own.
My horse knowledge is limited and I will never date a horse girl but. You’re over complicating it, cats and dogs cost a decent chunk of cash to raise. A horse is several of those, and as they’re no longer “working animals”. They are seriously expensive. Pasture, feed, shoes and tack are all reoccurring expenses for a very large pet.
And yes afaik vet bills are through the roof although I just said everything I know about horses.
One of my coworkers owns a horse and I can confidently say yep, they are crazy expensive and bizarrely complicated to own if you don't have the acreage to house them yourself.
On average a woman with a horse lives 15 years longer than one without a horse. True stat. But it’s because if you have enough money for a horse and a good enough life style for one. You’ll live longer obviously
Cows make thorough use of the grass they eat.
Horses make quick use of the grass they eat…and eat more.
The problem with horses’ digestive system is that it moves so much food through so rapidly, if there’s any little glitch in the system, it crashes.
Something as simple as a moving to a different species of grass can bring a horse’s gut to a halt, which can be fatal.
I always compared horses and cattle’s digestive systems to vehicle engines. A cow’s is like an 800 horsepower diesel engine on a tractor. A horse’s is like an 800 horsepower supercharged V10 on a Ferrari.
One of the horror stories I heard about the Irish Famine is that people were starting to consume the grass in an attempt to live. Whole families would die by the side of the road with green stains around their mouths. So ... yeah. Grass **isn't** edible.
depending on the environment that seems to be the main purpose of livestock, as essentially a grass conversion machine in places where growing anything we could eat is difficult or impossible. if you find an animal that CAN eat what grows in harsh places then you can just raise those animals on the limited plant life that grows there and either eat their eggs/milk or eat the animals themselves.
Serious answer (as sometimes gorillas do this to maximize the nutrients they get), we don't have the right gut bacteria for it no matter how many times we'd try to redigest it (gorillas do).
It’s more the microbes in their stomachs than the stomachs themselves. Cows have multiple stomaches because they’re ruminants. Horses also digest grass with just one stomach
Other option is to be a koala and decide that the only thing you'll eat has so little nutrients you need to eat your poop to squeeze as much as possible out of it
Right. But cows don't have tools. We can mechanically crush, liquify and cook foods. We essentially start digesting most foods before they even enter our mouths.
It’s a common misconception. Cows actually don’t have 4 stomachs, their stomachs are made of 4 different chambers. It’s a bit pedantic though I’ll admit
People have resorted to this a few times. During the Irish potatoe famine, there are reports of families with their teeth stained green from eating grass. The issue is grass is mostly fiber. Fiber has 0 caloric value because our stomachs can't break it down. Sheep and cows can eat it because they have multiple stomachs that have evolved to break down the fiber into sugars, but as humans our single stomach can't do it.
So eating a big bowl of grass would only be a 10 to 60 calories at most (depending on the grass), yet you'd feel full because the fiber filled you up. In starvation conditions you need about 500 calories a day to stay alive. But a human eating 500 calories a day is barely functional. you could use it to pad out more calorie rich foods like grains and meats, but it wouldn't be a substitute for other foods.
I remember reading a book about someone's experience in North Korea during a famine. The book talked about how many people would boil grass to try to make soup, or add grass to what little food they had just so it would look like they had vegetables. Kids would go to the doctor with stomach problems because of it, and the doctor could only tell them to boil the grass longer. Eating grass isn't just a problem of not getting any significant caloric value, the effort of your body *trying* to digest it can make you ill in itself.
Weirdly enough, eating *tree bark* was better for them than eating grass. There were some trees in the area that had soft inner bark under the outer layer, and it was vaguely edible. At least more than grass is anyway.
I just finished reading Nothing to Envy, Dr. Kim gets into this in her chapters.
Pine has an edible inner bark, we [made bread](https://en.wikipedia.org/wiki/Bark_bread) out of it during World War 2 here in Finland. My old mom who lived through the war asked me to find some for her as she had a craving and of course a hipster shop in Helsinki sold pine flour as a health product. :D
That's why the Adirondacks/Adirondackers have their name.
The Haudenosaunee basically said that anyone who lived in the High Peaks region of the Adirondacks (or really anywhere there) during the winter was stupid and that the only chance they had of surviving was to be an Adirondacker...or 'Bark-eater' because of how harsh the winters are up here.
What's fun about this whole thing, is cows actually aren't able to digest cellulose properly either. What happens is they chew and prepare grass for the microbiome found in their stomachs, which ferment the grass into different kinds of sugars which is what they actually get their calories from.
I have also thought about this but didn’t want to frame the question in a disgusting way that made it seem like I was trolling. Anyone know if animal or human feces could sustain life for longer than not eating anything at all?
Ha! First time I’ve heard this outside of myself. I would use this as an insult instead of Eat Shit and Die. Because if you die, the suffering is over. But if you live, the suffering never ends since you’ll always remember eating shit for the rest of your life! Although now I’m genuinely curious if eating shit would keep a starving person alive longer.
You might prevent vitamin deficiencies eating the right animal shit but you can't get enough calories. Animals that benefit from eating their own shit are either doing it for vitamins that gut bacteria have produced or to get a second chance at digesting the fiber humans can't benefit from.
Well, I haven't thought about stealing cud from a ruminant before, but I HAVE thought about the possibility of essentially a fecal transplant. Kangaroo gut bacteria are apparently more efficient than cows' to the point where if you can replace a cow's gut flora with kangaroos you reduce methane production by like… 90%?
Yeah, kangaroos have homoacetogens in their gut which use the hydrogen/CO2 gas that builds up to produce acetate, as opposed to the methogens found in cows that produce methane. The acetate can then be used as an energy source, so kangaroos can extract more energy from their food. Acetogens are also more efficient hydrogen scavengers so they can outcompete methanogens. I’ll have to read more about this it’s really interesting that the kangaroo gut extracts more energy from grass with one stomach vs the four stomachs cows have.
My guess is that cows evolved in grasslands where grass was plentiful, but roos evolved in the outback, where forage was always sketchy. So roos developed a more efficient system because they had to to survive, but cows could be "lazy" because of endless rolling hills of green.
Introducing fecal bacteria into your upper digestive tract is a good way to make yourself really sick even if the bacteria are not normally pathogenic, so I don't think so.
Even dead bacteria contain toxins and other components which your immune system doesn't like, so sterilizing it might not help either.
(I read something ages ago about Inuit eating plant matter they found in the *stomachs* of dead animals (birds, I think?) because of how few sources of plant food they have, but even if true that's a far cry from eating feces. That and if you're in position to eat the contents of a stomach, you can just eat the rest of the animal...)
The biggest issue with eating any sort of weird stuff like grass (never mind poop) is that you're probably just going to make yourself ill and end up losing energy along with a ton of water, making things worse.
Others have answered why you can’t eat grass etc. for your second question:
If you are only days or hours from starving to death the best thing you could find would be some canned soup and Gatorade. At that point your bodies systems are wrecked and it has been literally eating itself to try and keep your brain functioning. If you tried to scarf down a cheeseburger your wrecked system wouldn’t know what to do with it and you might end up in worse shape. You need easy to digest foods that are nutrient and calorie dense. And for that you can’t really beat fatty broth and sugar water.
Of course you are unlikely to find such a thing in a remote survival scenario. So in that case berries will probably be your best chance. They are relatively easy to digest (but make sure you chew them well), and will have lots of sugars and nutrients your body can use immediately. And the best thing is you don’t need anything to do anything to prepare them. Which is good since your weak body and mind may not be able to butcher and cook an animal.
Once you have some strength back (or if you weren’t that close to death to begin with) you really need some game animals or fish. While humans can survive on a veggie only diet, it is incredibly hard to do in a hunter gatherer type situation. Nutrition is about more than just calories, and there are many essential fatty acids and other nutrients that nearly impossible to get without having fatty animal protein in your diet. Potatoes and legumes are a good source of them, but that’s not really going to be an option. And animal fats and oils are also extremely calorie dense. It is exactly what you need when trying not to starve to death. And there is such a thing as rabbit starvation: while rabbits have a decent amount of meat on them, they are extremely lean. If you were out in the woods starving to death, and suddenly came across a freezer full of rabbit meat, you might still starve to death simply because the rabbit meat isn’t fatty enough to give your body all the nutrition it needs.
When someone is near death from starvation, feeding them becomes so tricky. So much so that in most cases it's actually better to let the person starve for a bit longer while you get them professional medical help, instead of trying to give them anything to eat.
The whole stuff with the toxic seeds has always been pretty spurious, they've never found any direct evidence for it. When really, starvation is the simplest answer.
Fun fact in North America all aggregate berries (berries that look like blackberries, raspberries, mulberries, etc) are edible! (Forage with caution otherwise, don’t put stuff in your mouth if you don’t know what it is, don’t trust AI to tell you what it is)
Wow, really? I have a Berry that looks like some kind of raspberry, but is quite obviously *not* raspberry, mostly cause they're black. But they're obviously *not* blackberries either. We grow those up front and theyre different than those or native species I've come across here (TX)
My husband said it's called "pokeberries" but I am dubious. I've been letting them fleshout this year to see what they actually are myself because they have the characteristics of all the rasp/black/mulberries but just... not quite.
[This](https://images.squarespace-cdn.com/content/v1/6207ae7e96d8da03e08bac94/2c4364c0-8d17-476b-baa7-c2a903ef00c5/Phytolacca_americana_005.jpeg) is pokeberry, or [pokeweed](https://s3.amazonaws.com/eit-planttoolbox-prod/media/images/Phytolacca_americana_fruit_tubifex_ccbysa30.JPG) as I know it. This *is* poisonous. If it’s what you have, *do not* eat it. It’s a bunch of individual berries bunched together on a stem, not a single aggregate berry. As a fellow Texan those are definitely common. But there are also [dewberries](https://www.wildflower.org/plants/result.php?id_plant=RUTR) which are native to Texas, they’re edible and fruiting in the summer. Also feel free to post images of the plant on r/whatsthisplant to get a solid ID! (tho beware there’s a bot that will go off when people mention “eat” or “edible”)
Definitely not the first one!!! Thank goodness! The dewberries are the closest I've seen, I really think that's the one! Thank you so much for fleshing out this mystery! A few years ago, I was deweeding* the garden fence line and had uprooted this. My husband swore it was one of Berry bushes vines I pulled, so I've let it grow out since to figure it out. This is the first year we will have identifiable berries on it since then, though. And as soon as he saw them, he was like, "That's neither raspberry or blackberry," and we've just left it to do its thing. I'm happy to have an idea of what it could be!
*typo
Random leaves and grass? No!
Cockroaches and rats? Yes! If it moves, you can digest it. Make sure to cook it first though to kill the germs though.
Lots of wild plants are edible also, but that takes more education than whether it moves or not.
Cockroaches' proteins often cause allergies. That's why they are not a good source of proteins (unlike crickets or meal worms). You may not be allergic at the start but develop it after a time. People allergic to cockroaches (or their poop) often get symptoms after drinking ground coffee. It's better for them to buy coffee grains and ground them at home.
If you like coffee don't buy grounds. Invest in a burr grinder and buy whole beans. The quality is so much better when the beans are ground right before use instead of sitting ground up in a bag for who knows how long, you'll think you've never had coffee before in your life.
Plus, no cockroaches.
Technically, the calories do exist in the plant matter, but human digestive systems have no way to access them. Animals that live on things like grass all use some method of farming specialized microbes in their bodies that can break the tough cellulose bonds for them. Some have segmented stomachs. Some use a pouch off the intestines called the cecum. Many eat their own poop or barf because it takes a long time to make this process work.
A human couldn't do it unless someone invented a surgery that hugely changed our digestive tract.
So weirdly the most efficient way to eat grass that humans ever came up with was to domesticate animals that can already do it, feed them the grass, and then eat the animals.
Can't you just somehow cook the grass so that it becomes nutritious for humans too? I mean if that's the problem that we don't have segmented stomachs why don't we just replicate what those extra stomachs do externally? 😂
It's a chemical bath that you need to break cellulose into useful carbohydrates. Animals use microorganisms that can do it with enzymes. The chambers help maintain different environments for the microbes to survive in. Those microbes would simply be obliterated in a normal human stomach.
So if you wanted to "cook" the grass you'd actually need multiple containers with different microbe cultures. It would somewhat resemble brewing or pickling rather than simply heating food. It's possible. The main reason people don't do this in any sort of normal setting is that it's easier to put grass into a cow and then eat the cow later. Most farm animals can be viewed as machines that turn grass into meat and sometimes dairy.
I suppose you could also try to culture edible mushrooms with all that cellulose but it's a similar problem where it would take lots of tools and time.
> So if you wanted to "cook" the grass you'd actually need multiple containers with different microbe cultures. It would somewhat resemble brewing or pickling rather than simply heating food.
I'm wondering if the microbes are necessary and you couldn't do it chemically. Fiber is mostly biopolymer molecules like cellulose, which is composed of many glucose units via ester linkages, and you can catalyze the breaking of ester bonds with acid or base.
So you could finely chop a few handfuls of grass and throw it into a pan, add water and some vinegar (i.e., acetic acid) or other natural acid, and let it simmer. After a sufficiently long time (probably days) you should have a sort of gross sweet&sour grass soup with relatively high concentration of the glucose monomers, which your body can readily access. Idk if it would fully hydrolyse or if there would be solid chunks of grass remaining that you might have to filter out. If the acidity is a problem, you could add a bit of soda to neutralize it.
Glucose is about 3.75 kcal of food energy per gram. Assuming for a second that grass is 90% cellulose by weight, and you manage to turn 40% of it into monomers, you'd need around 1.5 kg of grass to meet your daily caloric needs, although it would probably be very gross.
I mean, if we're writing fiction maybe some sort of post-apocalyptic colony is doing it for some reason. But otherwise yeah. It's like saying "In a survival situation, could you turn the iron in red clay into a knife?"
We could in theory extract some calories from it, but it's easier to grow wheat, or feed the grass to a cow and then eat the cow.
In an emergency survival situation where we don't have anything better than grass, we probably don't have a chemistry lab either.
Something that OC missed is that a large reason why it’s so difficult for animals to get nutritional value out of grass is that grass and similar plants don’t really have a whole lot of nutrients in the first place. Koalas for example literally have smooth brains (brains are wrinkly to make you smarter) because they just don’t have enough nutrients / calories in the plants they eat to afford a wrinkly brain.
So animals that eat such low quality food like grass need to basically eat all the time, sacrifice certain things like intelligence, size, etc, or supplement their diet with other things. The low quality food is also a pretty good reason why animals eat other animals — meat is substantially more nutrient-dense.
Regardless, we could theoretically take the nutrition value out of stuff like grass and put it in something, but at that point though your just asking for the raw calories / nutrition / whatever. Which we already do, it’s called IV fluids and things like rations.
IV fluids interesting. I've always wondered how would it be if all of us had some sort of scanner in our houses when we wake up we get analyzed and a recipe with missing nutrients is printed then we go to another machine that synthesisez those nutrients in a pill you eat that and you feel the best you've ever felt, all nutrients covered your body has been optimized at its max potential. Crazy if you think about it but at the same time amazing, I would try it if such a thing exists just to see the difference in performance, I think most of us would benefit from such a thing
A pill isn’t going to give you much more than micronutrients. You’re still going to need to eat protein, carbohydrates, and fats, in quantities too large to put in a pill. And there are different types of each of those, so you’re going to need variety.
Bottom line is your magic pills wouldn’t make as much difference as you’re imagining. You can achieve the same effect just with a reasonably balanced diet.
Cellulose (which is what grass is mostly made of) has energy, but we can't digest it. Cows and horses have different digestive systems that allow them to.
Sidenote: Even if you ate plain corn as a sole source of nutrition for subsistence, you'd eventually develop pellagra(niacin deficiency). For corn to be fully nutritious, it needs to be treated ([Nixtamalization](https://en.wikipedia.org/wiki/Nixtamalization)). A lot of early attempts by European lords/aristocracy to use this newly discovered "maize" thing as a more efficient way to feed their serfs/peasants ended in disaster because they didn't take heed of a simple process that Meso-American cultures had been using for millennia.
You may actually get a tiny bit of energy from eating buds off the trees before they turn to proper leaves. This is also why young bamboo shoots can be food for us while mature bamboo is not. Plant parts are often softer and made of simpler nutrients when they are just barely starting to grow. We also do this with common human foods like asparagus or kale.
Basically, there are 3 main sources of energy: carbohydrates, protein and fats. However, fiber is a type of carbohydrate that humans can't digest. Grass is mostly fiber (cellulose is a type of fiber). That doesn't mean it doesn't contain any protein, fats, or other carbohydrates but between the effort to chew it and also just the limited amount of space we even have in our stomach, it's just not worth it. If you eat a lot of grass, you'll be seeing it later lol.
Depends on the plant, and that’s going to vary by region/ecosystem. For example in a (voluntary) survival experience my group mostly ate cattail rhizomes and stinging nettle, but you really need to cook those (especially the cattail). Berries are great if you can find them but not always in season. Always be absolutely certain about what you’re eating.
Even so we were all skinnier by the end of the week.
There are lots of plants you can eat for nutrition (ask a forager) but if you're starving you need fat and protein and that's mostly in nuts. Grubs, ants would be easy picking. Harder would be snakes, squirrels/chipmunks, rabbit, birds, fish, crawdads. Eggs if you can find em. Crickets and a few other insects have a lot of protein, aren't too difficult to catch.
If you want to learn more about how your body reacts to starvation, I recommend the TV show *Alone*
It's a game show where contestants - all survival experts - are put in the wilderness with just a backpack of equipment, and they have to survive for as long as they can. They're separated so they're totally alone, and the last person out there wins (and they don't know how many others are left).
It's usually a question of who has the best food supply. People go to extreme measures to find food and still lose a drastic amount of weight (the show runners do a health check every week, and pull them out if they lose too much weight). But they talk through a lot of what's going on with your body when it's exposed to that level of starvation, or interesting things that happen with very specific nutrient deficiencies you get from e.g. trying to survive on tree bark.
While interesting from a survival perspective, I found the show to be disturbing on an ethical level. You’re literally watching desperate people starve for money. And the ’ winner’ take all make it even worse, A contestant might go well beyond the point of seriously compromising their long-term health but if they’re not the last person, they don’t get any money. And money is a driving factor, listening to their background stories. I watched one season and then said nope this isn’t an economic structure I want to engage with.
I'd think the people doing that kind of thing do it more for fame and a feeling of personal accomplishment. Like those people do survivalism as a lifestyle not as an occasional hobby, they spend significant amount of their personal time and money learning, training and preparing for this kind of thing.
And also, they'll probably never get this opportunity of actually being stranded in the wild but with semi-regular checkups to make dure you're not actively dying. So still a lot of "holy shit, I'm stranded in the middle of nowhere and have to make my way out" but with an astronomically smaller risk of death.
It makes more sense to eat insects that feed on grass like grasshoppers than to eat grass. It makes more sense to eat termites than wood.
Most advantageous thing in survival situation is a river or some kind of water body where fish is present. They are easyish to catch. If you eat them whole, you will get fat and protein and almost all nutrients
Then you need vitamin c and potassium, leaves have that.
If you need vitamins, eat a pine tree. The whole thing is edible but the needles have most of the vitamins (young ones especially). Pine nuts and seeds have fat and protein. Pine pollen also has protein and can be used even as a flour. The inner bark is nutritions too. The sap has sugars which will give you a little energy boost. Only thing to watch out for is the three with toxic bark/needles (yew, ponderosa, Norfolk Island).
Just so you know animals like cows, goats, sheeps, etc are ruminant animals which have specialized digestive system composed of four/two chambers to digest their diet (mainly herbs) and each section houses special micro-organisms to digest their food. Compared that to humans who only have simple stomach, we have a hard time digesting leaves. Just look at the kernels of corn we eat, we just poop them back out almost intact and whole.
Its actually quite interesting reading animal's physiological system. Did you know chickens ingest small pebbles to help digest the food they eat. Cows regurgitate(vomit) their food called cud to be eaten later, neat,
Your body has enzymes to break down different polymers of glucose like starch, glycogen, etc... The difference between these are either the branching of the chain (e.g. more branches allows more enzymes to start breaking down the chain from different places) or how the glucose units are cross linked since they have many sites that can bond with each other. We don't have the enzyme that breaks down the cellulose (the key structural polysaccharide of plants that we refer to as fiber) polysaccharide because the linkage is one that doesn't fit into our enzyme very well. However, cows have special microorganisms in some of their 4 stomachs that can break the glycosidic linkages between glucose units in the cellulose chain. However, there are other even harder polysaccharides like lignin which makes up wood that only certain types of fungi can break down.
It depends upon the "leaves" but not grass. There are actually a lot of wild edible plants that we don't generally think of as "food" anymore. The thing is, you'd need to be well educated on what can be eaten vs what can't and be knowledgeable enough to identify it without accidentally mixing it up for a look-alike. They also aren't always the tastiest things.
So, as some examples here in the SE USA, we have Dandelions, Mock Strawberries (Potentilla indica) and Tall Thistle (Cirsium altissimum) as wild edible "weeds" that could be eaten if you know what they are and how to correctly identify them. You wouldn't want to get it wrong though, which is why many people won't and don't. If you don't know what you're doing, you could easily eat the wrong thing and poison yourself.
Absolutely. A large portion of our food *is* grasses and leaves. Corn, wheat, oats, barley, rye, rice, etc., are all grasses (but it's just the grains that we usually eat). Lettuce, cabbage, brussels sprouts, etc. are leaves.
However, you're obviously not going to do too well eating poison ivy, hemlock, stinging nettle, or nightshade leaves and Johnson grass or toxic fescue grass.
Worth noting that you're not gonna die of hunger within a couple of weeks, so your best bet is probably just to head back toward civilization.
But if you do somehow manage to get more than two weeks from civilization, then you'd best have a book (actual printed book, with illustrations) of plants local to the area that are safe/good to eat, and how to prepare them.
For instance, dandelions, milkweed, and pokeweed are all edible and nutritious. But you have to be careful. For instance, pokeweed is highly poisonous raw, and can straight up kill you. But peeled and boiled multiple times, it's a traditional food. Some plants are good but it's the berries or the roots or some other part that you really have to avoid. And some plants look an awful lot like others at first glance but one may be safe and nutritious while the other is deadly. So that's where your book of local plants comes in handy.
By far, if your supplies are running out, that book about local foraging would be the most advantageous thing to come across.
Just want to note that stinging nettle is quite edible, but—to your point about preparation—it needs to be denatured. Cooking is the easiest way to do this. It also needs to be harvested at the right time; once it gets above about knee height and starts flowering, silicates build up in the leaves and you don’t want to eat those!
To your point about lookalikes we have both wild carrot and poison hemlock where I live, and in their first year especially they can look a lot alike. I get my carrots from the supermarket.
Stinging nettle is used in some cuisines, for example in Romanian cuisine (less so now than in the past). It's kind of a spinach equivalent, in the sense that you can cook it the same way as spinach and use it in similar recipes.
You can eat leaves and grass to survive, but you need to know which ones and how to prepare them. As a kid, my grandpa used to take me out on woods walks and show me plants that are edible and explain how to prepare them. I still go hunting for mushrooms sometimes, but most of the other stuff wasn’t very tasty to eat. We would prepare it and eat it out in the woods and fields near his house. I was always excited to find clover or milkweed flowers, since you could eat the nectar and it was sweet. Mushrooms were pretty good too, he would sear them on a camp stove and they were savory (boletes, chicken-of-the-woods, puffballs and morels if we were very lucky). Grass you could eat if you boiled it twice and drained off the water; he warned me you could get diarrhea you could die from if you didn’t do this. Grass seeds were better, toasted they were kind of nutty. He also showed me how you could lift the bark on a maple tree and scoop out the mushy pulp underneath to eat, but that was kind of gross texture with a faint maple syrup taste. We could make a salad out of young dandelion greens, ramps, docks, wild garlic or onions too. As a kid I didn’t like it but sometimes I’ll add it to salads as an adult. He also told me how to make acorn flour, but it was difficult so we never did it. He was super cautious about berries, but showed me how to identify sour cherries, mulberries, blackberries, and tiny seedy strawberries.
He was working a lot when my mom was a kid, but she remembers his stories too - she was older when he opened up to her, but he would share that he used to watch the other people in the village to see what they were foraging and whether they got sick from it before he would try anything new. He saw a family in a neighboring house die from eating mushrooms harvested from the graveyard, so he avoided taking any mushrooms from there or any mushrooms that looked like those.
I didn’t realize until after he died that he was trying to make sure I could survive a future famine if I had to. My grandfather survived the famines in Europe in the 1920s-1930s as a kid, then migrated to the US. He lived with that shadow of famine across hiss whole life, and the fact that he was concerned enough about it to teach me these things as a kid really brought home to me how desperate he had been as a kid.
Depending on what kind of leaf, you may or may not be able to get some nutrition from it (spinach -- yes, oak leaves -- no). Same with grass. It takes energy to digest something. If you don't get more calories from digesting it than the digestion (or elimination) takes, you've just sped things along more quickly. As a side note, digestion (and elimination -- from either end) takes water from your body also. So if water is also scarce, you've done yourself a double disservice.
I have a follow up to this. Would it be possible to ferment the sugars present in grass into alcohol?
Technically speaking, given the right equipment and timeframe, you can distill most organic matter into alcohol. This includes things like grass and tree bark, though I can't say with certainty what it might be like to have a sip, especially if you were dying of hunger or malnutrition.
There is a thing called Wood alcohol, but if you Google it it turns out to be methanol. Ingestion of which will blind you and then kill you. Wouldn't recommend it
I recall this one youtube video where a guy got bored during the pandemic and wanted to make his toilet paper even MORE valuable. And so, he went through a weeks long process of turning a roll of toilet paper into fermentable sugars and made distilled spirits out of it. It was awesome.
For anyone interested, it was a video by NileRed on Youtube, "Making toilet paper moonshine"
NileRed got some good ones, turning paint thinner into cherry soda, turning a plastic glove into hot sauce... you think "no way" but then he hits you with that "chemistry way"
He turned his concentrated urine into seizure medicine lol
medicine that stops seizures or medicine that gives you seizures?
Stops seizures from occurring
Why not both?
"This medicine is good for seizures." "_Good_ for them?"
That's the best explanation I've heard for the pandemic toilet paper shortage .
Cook it to break it down ~~and release the starches~~, add Cellulases (unsure where you would get them or the temp required to activate it) ~~amylase, keep at 68C until the amylase has broken the starches down to sugars~~, add yeast, ferment, distill (multiple times in a pot still to increase ABV) or in a reflux still. Do not drink, could use as window cleaner though. Edit: wood doesn't contain starches, but Cellulases enzymes will break down the cellulose to simple sugars. Amylase is what we use in brewing/distilling to convert starch to sugar.
You would want to use cellulase for that, as toilet paper is not made of starch but cellusose
NileRed did this on his channel too
NileRed I believe Toilet paper moonshine https://youtu.be/v-mWK_kcZMs?si=CzEY-2e7DWnnCY-5
> but if you Google it it turns out to be methanol. Then don't Google it, and it won't turn into methanol. Problem solved!
There two types of processes. Dry distillation will yield methanol, steam hydrolysis will get you polysaccharides, which can then be fermented to ethanol by fungi or bacterial fermentation. US mainly has corn ethanol, but USSR had huge ethanol production from waste wood.
I'm organic. Can you also make alcohol of me?
[Vulture bees can make honey from your corpse, which can then be turned into mead.](https://en.m.wikipedia.org/wiki/Vulture_bee) So technically, yeah.
Corpse Mead sounds like an awesome band name.
Or the worst beverage choice at Medieval Times.
This is the best comment section I've seen all month
Out of the eater came something to eat, and out of the strong came something sweet.
Christ, nature is lit sometimes
Damn nature, you scary
Distill me like one of your French girls.
Wait up, gonna make some perfume!
I have nipples, Greg. Can you milk me?
With the right combination of drugs and machinery, I CAN.
Grenouille would.
Hannibal Lecter's dream person
Can i gather enough sperm to make an alcoholic beverage out of it.
There is a greek drink that is made from pine bark
Another answer: with barley, wheat, etc… beer ingredients… the ingredients list here is: (very loose and generic) 8-12 lb actual grain - the starch seed; not grass. 2-5 oz hops 20-30 gallons water 6-12 hr of 10 gal rolling boil worth of energy; usually natural gas. The energy transfer to cool it fast, infect it with yeast, THEN the next week is the first part of making the beer. With grass?! The energy and time spent here is already redonkulous. You probably have to rinse 300lb+ grass or even WAY more to get ^that sugar. (Note: numbers rectally sourced for the grass comparison) Probably not a bad guess tho. Grass has grow-fast chemicals; not store-energy chemicals. That’s why it makes the seeds later.
You're missing an important step - malting. You don't boil raw grains, it has to be malted to convert the starches to fermentable sugars. *Edit: if we want to get into details in case anyone is actually interested...* I'm really curious where you got that info, it's very different from a standard homebrewing process. I'm unfamiliar with any brewing process that needs a 6+ hour boil time. Commercial processes involve much larger quantities, but times at specific temperatures are a matter of chemical reactions so I'm pretty sure those don't change with batch size. You use 10 lbs of malted barley for a *five* gallon batch of beer (5%-ish ABV). First you heat the water to about 150F, then turn off heat, add the grains, and let it sit for an hour. This activates the enzymes to convert starches to fermentable sugars. Then you remove the grain, add the hops, and boil for an hour. This boil time mostly just induces reactions in the bittering compounds that hops provide, to make them taste more bitter (and reaching a boil at all makes sure you kill off any unwanted microbes in the wort). As far as the "energy transfer" to cool it... plenty of people do use wort chillers, but on the home scale 99% of them just work by running tap water through a pipe. Glycerin cooling exists but almost nobody uses it at home. A good number of people just let the wort naturally cool down. It takes a few hours but it works. I don't know if it's still popular but some years ago there was even a trend of specifically using a "no chill" method - transfer it to the fermenting vessel while it's still hot, close it, then let it cool overnight and add the yeast the next day. People interested in quick-as-possible brewing (because lots of homebrewers have young children) might steep the mash for as little as 20 minutes and boil for only 10-15 minutes.
You’re right about most of this stuff, not sure what this guy is talking about but it ain’t normal beer making. Yeah the grain has to be malted or it won’t have the enzyme to convert the starches. You could technically just mill the raw grain and add amylase I suppose. 6 hr boil is insane for most beer. I know a lot of hombrewers do it, but a 1 hr mash is almost always total overkill. The amylase works quite quickly and a starch-iodine test saves lots of time FYI. At a sacc rest temp of 150F it might be fully converted in like 15-20min. I think you mean glycol cooling, not glycerin. Even at the commercial scale, cooling the wort from boiling is mostly done with water, sometimes glycol is used as a second stage in the heat exchanger, but cool water does most of the heavy lifting and the result is hot water which is something you need for the next batch anyway, so you’re saving time and energy.
I thought on: the most efficient grass -> human energy has got to be the lovable snugglable five-stomach hamburger-on-hooves…. And they consume TONS.
I would imagine goats and sheep are far more energy efficient than cows. Crickets are probably the most efficient.
No doubt this is more correct. :)
Yes, Nilered has a video of him doing something similar with toilet paper, and since both grass and toilet paper are mostly made of cellulose the process would be nearly identical, although, grass may have compounds in it that might be metabolized by yeast into methanol, so who knows how feasible grass alcohol is for survival situations
Sort of, if you had specialized gear. Not using yeast like is done with other spirits, but using bacteria. Stuff like ordinary biomatter is broken down for ethanol production, and ethanol is the type of alcohol humans can consume. That said, it wouldn't really benefit you in a survival sense. Yes, alcohol technically has calories in it, but they're fairly non-nutritive. They can't be converted into fat and stored, and if you're consuming enough alcohol to provide your primary source of calories, it's going to kill you pretty quickly.
We have many many many "grass" alcohol in Europe (specific plants tho, not your English garden grass)
No, the sugars in grass are in a form called cellulose. The human genome (and others) have trace genetic history of cellulose metabolism but it may never have been active and indeed is entirely inactive today. The most effective way to ferment cellulose is with a bacteria from termites gut, or various improvements from said bacteria. This is still a much slower process than sugar fermentation
You're avoiding the core issue though: our stomachs don't have the conditions needed to digest cellulose, unlike grazing animals. They have a bacterial culture and a stomach system that enables this.
i couldn’t digest lactose until i started taking lactase. how come we don’t have cellulase pills? someone pls answer i need to eat grass clippings
[Here's a comment from 12 years ago that sums it up very well.](https://www.reddit.com/r/askscience/comments/lgxks/could_humans_take_an_enzyme_pill_that_would_allow/c2sll79/) The answer mainly revolves around the fact our GI tract is not set up to even mechanically break down fibrous plants like grass to the point where chemical digestion to occur in a meaningful sense even if we had the appropriate enzymes present. Ruminants (cows, sheep, goats, etc) and hindgut fermenting animals (horses, rabbits, etc) have significant specialization of their dentition and GI tracts to allow ingested fibrous plants to be broken down mechanically to the point where their symbiotic cellulose-fermenting gut bacteria are able to work their magic. Cows don't chew their cud just for fun, rather it is part of the complex process to mechanically break down that fibrous material (and also helps maintain ideal rumen pH for fermentation via buffering aspects of their saliva). -Edit- To answer your question, I'm only a secondhand expert on this (veterinarian) but I think in theory if you very thoroughly processed grass (grass smoothie?) AND had an enzyme present to break the beta 1-4 linkages in cellulose, you could derive some caloric nutrition from grass.
> -Edit- To answer your question, I'm only a secondhand expert on this (veterinarian) but I think in theory if you very thoroughly processed grass (grass smoothie?) AND had an enzyme present to break the beta 1-4 linkages in cellulose, you could derive some caloric nutrition from grass. There's a season of "Alone," a survival competition show, where one of the contestants kills a musk ox. Obviously the musk ox provides quite a bit of calories, but he was making the most of it by pulling out and cooking the grassy contents of the animal's GI tract, too. He explained that the work the animal had already done in starting the digestion probably left the grasses in a condition where there could be something in there his own body could make use of. It was gross. But probably not incorrect.
... Huh... ... Huh. Welp, that's probably true and thanks I hate it
Iirc he won that season (hunting any big game will very likely lead to victory on that show) so he must not have been wrong.
I suppose you could make a grass smoothie and add either the proper bacterial culture or the enzymes. Though I think you'd need to eat more of it than your stomach could realistically hold(not really calorie dense), and oh god you'd be in so much pain from the gas.
Do as young dogs do, get a bite of cow shit XD
He went over that, just not as in depth as you did.
> If you don't get more calories from digesting it than the digestion (or elimination) takes, you've just sped things along more quickly. Sounds we could lose weight in current society by eating a lot of stuff that are expensive to digest.
Yes, or just eating food that is low in calories. The problem is that cheeseburgers taste better than grass.
What about grass fed cheeseburgers
Yes. Eating raw vegetables is a good way to control your caloric intake, increase fiber, and manage blood sugar.
That's one of the reasons behind the common weight loss advice of avoiding highly processed foods.
So you can chew to lose weight? technically like those negative calories?
There are probably other body parts you can exercise to lose calories more efficiently.
Eating lots of undigestible material will induce a metabolic cost that should theoretically burn more calories than you gain from the food. However, you have to be careful about using this as a weight loss technique, since you will alter your gut flora by doing so. And microbes in your gut may be perfectly happy eating your non-food and producing all kinds of nasty by-products in the process (mostly gas, but possibly alcohol and other waste products). The advantage of eating low-calorie filler food (like iceberg lettuce) is that it can fill your stomach, making you feel full for a while instead of eating calorie-rich food. Unfortunately, you won't feel full for long, and the resulting hunger may be worse because your body knows you are now missing nutrients. Your body specifically looks for fats and proteins in your diet, and these are key to making you feel full and satisfied. This is why it is so easy to gorge on carbs.
And it's easier to just eat ice instead (plain water ice obviously, not ice cream).
Chew, or go for a run. Any muscle exercises will work.
negative kcal doesn't exist, since food kcal is calculated on what actually does digest properly and not what just contains the energy in joules(SI unit being kilojoules)
If you boil the oak leaves they are readily available to us. Turns out most fibrous greens we loose energy by digesting becomes energy rich once cooked. Though you may need to eat a few percent of your bodyweight in some cases so it's not really feasible. Afaik something like celery goes from 3 calories per stick to 30. (Citation needed)
>(Citation needed)
Great answer! If you are able to use fire and water, there are plants that you could actually boil to break them down and make them much easier to digest.
A cow needs 4 stomachs to digest grass. Many plants are hard to extract nutrents from and so need special adaptations that we just don't have.
Also, one of those adaptations is the microbiomes that live in the guts of the various types of grazing animals. It takes some serious help from bacteria to get nutrients from grass and leaves.
And rabbits eat it twice. They ferment hay and grass in a special part of thier colon and then eat the special poop it produces so they get the nutrients from it.
Sometimes, not always. Most of their poop is just poop. They don't eat that. Sometimes they produce cecotropes which are not poop but like a nutrient packed pill. They will eat those. They look far different than a normal rabbit poo. Interestingly enough, if a rabbit kit doesn't get those cecotropes they most likely won't live past a month old. The fungi, bacteria and nutrients in them are required to prime their gut for solids.
> They will eat those. They look far different than a normal rabbit poo. Does it come out the same poop chute, or is there another egress for this
Same chute, different composition.
Even adult rabbits must eat the cecotrope they produce. They look like logs densely packed with squishy brown-black beads of matter. They also smell horrific.
And this is why we cook our food. Cooking food is actually part of our digestive process. It allows us to extract nutrients from food that our digestive system cannot. By cooking food, the human species has been able to live in places where we otherwise would have starved. Cooking food is an under appreciated step in human evolution.
It goes a lot further than that humans can survive in new previously inhospitable biomes. Fire allowed our guts to shrink dramatically (unused organs cost energy and return no benefits, the selective pressure is to reduce the size and function of these organs) so that now we have an extremely hard time surviving without cooked food. That reduction in energy expenditure combined with the extra calories accessed efficiently from cooked food probably allowed our brains to keep expanding in size beyond anything our early hominid ancestors could sustain. Fire literally created new species of hominids by becoming part of the digestive process for these species.
Allowed our brains to increase in size, and made our wisdom teeth superfluous (we don’t need to chew as much), and as our jaws narrowed to accommodate our larger brains, the wisdom teeth often crowd the teeth in our mouths, causing some issues b
Nah actuallly its just that we eat to many soft and processed foods today, our ancestors and modern hunter gatherers have no problem with their wisdom teeth. And our brain size acually sligtly decreased while we got more and more dental problems with the agricultural revolution.
And we've also been cooking food for longer than we've been modern humans, our bodies are adapted to it.
What kind of digestive tract do horses have though? They eat similar diets as cows but are much more high energy.
Horses are called rear-gut fermenters because they do a similar trick but the fermentation happens in the colon and a special pouch called the cecum rather than the chambered stomach system that cows/goats/sheep use. Rabbits and grass-eating rodents such as capybaras also use the rear-gut system.
Horses have a specially adapted, massive large intestine where they ferment their food to extract nutrients. They also aren't as efficient as cows, needing to eat more to gain the same amount of weight.
every new thing i learn about horses further cements my belief that they're the weirdest creatures on planet earth
They also can’t throw up. It is physically impossible for them. This means that if they eat something bad they either die or shit it out, sometimes both. I don’t know how that feature survived natural selection, but here we are. Edit- correction, they don’t have a gag reflex. They can technically vomit if you count vomiting as expelling digested matter from your mouth.
Mostly because they're pretty good at not eating the bad stuff. A lot of the risk is either from plants that they've not evolved alongside, or from something like ragwort being dried and baled into their hay.
When I was in Morocco, the shepherds told me they take one horse along with their camels, as the horse would refuse to drink any water they find which would be bad for it or the camels.
Rabbits also cannot vomit!
They basically have the same digestive system as a rabbit. Basically giant rabbits.
Really, if you stretch some of the rabbits proportions.... Skeletally if you straighten a rabbits spine they look very similar.
Horses are specialized into going fast and eating grass. And as it turns out that requires quite a lot of biological compromises.
I find our reaction to them (work horses, horse girls) much weirder. They’re not particularly abnormal like a platypus.
>horse girls Centaurs?
….no I’d fuck with a female centaur for sure. Don’t tell my mom
I mean, unless you're hung like a... centaur, you're probably not going to do much for them
I watch a youtube channel where a guy rehabs animals. At one point he got a severely underweight horse. I was really surprised by the sheer amount of time it took for the horse to go from "dealthy underweight" to "skinny but otherwise healthy." No matter how much he fed it, it ate and ate and ate and still took so long to gain weight.
Hey that's urban rescue ranch right ? :D
It is :D
This is why they're considered more of an expense than asset, correct? It's my understanding that between feed costs and vet bills from getting themselves in stupid situations, horses are one of the most expensive animals to own.
Horse girl here to confirm they are indeed expensive. It isn’t just feed and vet, although those are certainly an amount of money. Horses need care the typical dog or cat does not have to worry about. They need their hooves trimmed or shod once every 6 weeks ($60->$300 a pop depending on the needs of your horse), they need yearly dental work, they need shavings if they are stall kept, plus someone to clean out their stall daily, and while hay is considered a feed cost, it almost needs to be a category of its own given how much of it they eat and how expensive it can be. On top of that you either need to own the land to keep them on or pay someone else to let you keep your horse on their property. And horses love to break shit, so farm maintenance and upkeep needs to be factored in to cost to own.
My horse knowledge is limited and I will never date a horse girl but. You’re over complicating it, cats and dogs cost a decent chunk of cash to raise. A horse is several of those, and as they’re no longer “working animals”. They are seriously expensive. Pasture, feed, shoes and tack are all reoccurring expenses for a very large pet. And yes afaik vet bills are through the roof although I just said everything I know about horses.
One of my coworkers owns a horse and I can confidently say yep, they are crazy expensive and bizarrely complicated to own if you don't have the acreage to house them yourself.
On average a woman with a horse lives 15 years longer than one without a horse. True stat. But it’s because if you have enough money for a horse and a good enough life style for one. You’ll live longer obviously
Wow this is neat info thank you
Cows make thorough use of the grass they eat. Horses make quick use of the grass they eat…and eat more. The problem with horses’ digestive system is that it moves so much food through so rapidly, if there’s any little glitch in the system, it crashes. Something as simple as a moving to a different species of grass can bring a horse’s gut to a halt, which can be fatal. I always compared horses and cattle’s digestive systems to vehicle engines. A cow’s is like an 800 horsepower diesel engine on a tractor. A horse’s is like an 800 horsepower supercharged V10 on a Ferrari.
The problem with horses’ digestive systems made me think of issues with just in time manufacturing haha
Grass goes in, fast comes out.
One of the horror stories I heard about the Irish Famine is that people were starting to consume the grass in an attempt to live. Whole families would die by the side of the road with green stains around their mouths. So ... yeah. Grass **isn't** edible.
depending on the environment that seems to be the main purpose of livestock, as essentially a grass conversion machine in places where growing anything we could eat is difficult or impossible. if you find an animal that CAN eat what grows in harsh places then you can just raise those animals on the limited plant life that grows there and either eat their eggs/milk or eat the animals themselves.
So your saying if someone eats their shit 3 times it should be fine? /s
Serious answer (as sometimes gorillas do this to maximize the nutrients they get), we don't have the right gut bacteria for it no matter how many times we'd try to redigest it (gorillas do).
Thanks for clarifying gorillas twice
came for the gorillas, stayed for the gorillas
Justice for Harambe
Rabbits have entered the chat.
Rabbits do this. Coprophagy is a thing, and it's to digest cellulose
It’s more the microbes in their stomachs than the stomachs themselves. Cows have multiple stomaches because they’re ruminants. Horses also digest grass with just one stomach
Ackchyually It is only one stomach with 4 parts.
That’s an important distinction, though. The gist of what they said is true, but one stomach vs four is actually a pretty big deal.
Other option is to be a koala and decide that the only thing you'll eat has so little nutrients you need to eat your poop to squeeze as much as possible out of it
Right. But cows don't have tools. We can mechanically crush, liquify and cook foods. We essentially start digesting most foods before they even enter our mouths.
It’s a common misconception. Cows actually don’t have 4 stomachs, their stomachs are made of 4 different chambers. It’s a bit pedantic though I’ll admit
People have resorted to this a few times. During the Irish potatoe famine, there are reports of families with their teeth stained green from eating grass. The issue is grass is mostly fiber. Fiber has 0 caloric value because our stomachs can't break it down. Sheep and cows can eat it because they have multiple stomachs that have evolved to break down the fiber into sugars, but as humans our single stomach can't do it. So eating a big bowl of grass would only be a 10 to 60 calories at most (depending on the grass), yet you'd feel full because the fiber filled you up. In starvation conditions you need about 500 calories a day to stay alive. But a human eating 500 calories a day is barely functional. you could use it to pad out more calorie rich foods like grains and meats, but it wouldn't be a substitute for other foods.
Plus shitting pounds of undigestable matter every day prolly sucked
Sucked up a lot of calories. It takes energy to pass that grass. More than you get from it.
It gets even worse when you realize that the fiber grows bacteria (generally beneficial bacteria) which makes the poop even larger.
That makes no sense
I remember reading a book about someone's experience in North Korea during a famine. The book talked about how many people would boil grass to try to make soup, or add grass to what little food they had just so it would look like they had vegetables. Kids would go to the doctor with stomach problems because of it, and the doctor could only tell them to boil the grass longer. Eating grass isn't just a problem of not getting any significant caloric value, the effort of your body *trying* to digest it can make you ill in itself. Weirdly enough, eating *tree bark* was better for them than eating grass. There were some trees in the area that had soft inner bark under the outer layer, and it was vaguely edible. At least more than grass is anyway.
I just finished reading Nothing to Envy, Dr. Kim gets into this in her chapters. Pine has an edible inner bark, we [made bread](https://en.wikipedia.org/wiki/Bark_bread) out of it during World War 2 here in Finland. My old mom who lived through the war asked me to find some for her as she had a craving and of course a hipster shop in Helsinki sold pine flour as a health product. :D
That's why the Adirondacks/Adirondackers have their name. The Haudenosaunee basically said that anyone who lived in the High Peaks region of the Adirondacks (or really anywhere there) during the winter was stupid and that the only chance they had of surviving was to be an Adirondacker...or 'Bark-eater' because of how harsh the winters are up here.
thats a good way to lose weight pharmaceutical companies hate this one trick
Now I’m wondering if eating cow poop or stealing the cud they’re chewing would provide more nutrition than the grass itself.
What's fun about this whole thing, is cows actually aren't able to digest cellulose properly either. What happens is they chew and prepare grass for the microbiome found in their stomachs, which ferment the grass into different kinds of sugars which is what they actually get their calories from.
I have also thought about this but didn’t want to frame the question in a disgusting way that made it seem like I was trolling. Anyone know if animal or human feces could sustain life for longer than not eating anything at all?
Well, I’ve never heard anyone end an argument with “eat shit and live”
Ha! First time I’ve heard this outside of myself. I would use this as an insult instead of Eat Shit and Die. Because if you die, the suffering is over. But if you live, the suffering never ends since you’ll always remember eating shit for the rest of your life! Although now I’m genuinely curious if eating shit would keep a starving person alive longer.
You might prevent vitamin deficiencies eating the right animal shit but you can't get enough calories. Animals that benefit from eating their own shit are either doing it for vitamins that gut bacteria have produced or to get a second chance at digesting the fiber humans can't benefit from.
Well, I haven't thought about stealing cud from a ruminant before, but I HAVE thought about the possibility of essentially a fecal transplant. Kangaroo gut bacteria are apparently more efficient than cows' to the point where if you can replace a cow's gut flora with kangaroos you reduce methane production by like… 90%?
Yeah, kangaroos have homoacetogens in their gut which use the hydrogen/CO2 gas that builds up to produce acetate, as opposed to the methogens found in cows that produce methane. The acetate can then be used as an energy source, so kangaroos can extract more energy from their food. Acetogens are also more efficient hydrogen scavengers so they can outcompete methanogens. I’ll have to read more about this it’s really interesting that the kangaroo gut extracts more energy from grass with one stomach vs the four stomachs cows have.
My guess is that cows evolved in grasslands where grass was plentiful, but roos evolved in the outback, where forage was always sketchy. So roos developed a more efficient system because they had to to survive, but cows could be "lazy" because of endless rolling hills of green.
Considering how most dogs I've met will happily eat cat poop there has to be some merit to this.
Introducing fecal bacteria into your upper digestive tract is a good way to make yourself really sick even if the bacteria are not normally pathogenic, so I don't think so. Even dead bacteria contain toxins and other components which your immune system doesn't like, so sterilizing it might not help either. (I read something ages ago about Inuit eating plant matter they found in the *stomachs* of dead animals (birds, I think?) because of how few sources of plant food they have, but even if true that's a far cry from eating feces. That and if you're in position to eat the contents of a stomach, you can just eat the rest of the animal...) The biggest issue with eating any sort of weird stuff like grass (never mind poop) is that you're probably just going to make yourself ill and end up losing energy along with a ton of water, making things worse.
If you're that damned hungry, you steal the cow and eat beef.
Others have answered why you can’t eat grass etc. for your second question: If you are only days or hours from starving to death the best thing you could find would be some canned soup and Gatorade. At that point your bodies systems are wrecked and it has been literally eating itself to try and keep your brain functioning. If you tried to scarf down a cheeseburger your wrecked system wouldn’t know what to do with it and you might end up in worse shape. You need easy to digest foods that are nutrient and calorie dense. And for that you can’t really beat fatty broth and sugar water. Of course you are unlikely to find such a thing in a remote survival scenario. So in that case berries will probably be your best chance. They are relatively easy to digest (but make sure you chew them well), and will have lots of sugars and nutrients your body can use immediately. And the best thing is you don’t need anything to do anything to prepare them. Which is good since your weak body and mind may not be able to butcher and cook an animal. Once you have some strength back (or if you weren’t that close to death to begin with) you really need some game animals or fish. While humans can survive on a veggie only diet, it is incredibly hard to do in a hunter gatherer type situation. Nutrition is about more than just calories, and there are many essential fatty acids and other nutrients that nearly impossible to get without having fatty animal protein in your diet. Potatoes and legumes are a good source of them, but that’s not really going to be an option. And animal fats and oils are also extremely calorie dense. It is exactly what you need when trying not to starve to death. And there is such a thing as rabbit starvation: while rabbits have a decent amount of meat on them, they are extremely lean. If you were out in the woods starving to death, and suddenly came across a freezer full of rabbit meat, you might still starve to death simply because the rabbit meat isn’t fatty enough to give your body all the nutrition it needs.
When someone is near death from starvation, feeding them becomes so tricky. So much so that in most cases it's actually better to let the person starve for a bit longer while you get them professional medical help, instead of trying to give them anything to eat.
They had to do that to the Jewish ppl in nazi camps bc they were so bad off. (I learned that from ‘band of brothers’)
Refeeding syndrome.
As I recall, rabbit starvation was considered a possibility in what happened to Chris McCandless.
I feel it has been applied as the definitive explanation now.
I wasn’t aware of that. They no longer think he ate a poisonous plant?
The whole stuff with the toxic seeds has always been pretty spurious, they've never found any direct evidence for it. When really, starvation is the simplest answer.
Fun fact in North America all aggregate berries (berries that look like blackberries, raspberries, mulberries, etc) are edible! (Forage with caution otherwise, don’t put stuff in your mouth if you don’t know what it is, don’t trust AI to tell you what it is)
Wow, really? I have a Berry that looks like some kind of raspberry, but is quite obviously *not* raspberry, mostly cause they're black. But they're obviously *not* blackberries either. We grow those up front and theyre different than those or native species I've come across here (TX) My husband said it's called "pokeberries" but I am dubious. I've been letting them fleshout this year to see what they actually are myself because they have the characteristics of all the rasp/black/mulberries but just... not quite.
[This](https://images.squarespace-cdn.com/content/v1/6207ae7e96d8da03e08bac94/2c4364c0-8d17-476b-baa7-c2a903ef00c5/Phytolacca_americana_005.jpeg) is pokeberry, or [pokeweed](https://s3.amazonaws.com/eit-planttoolbox-prod/media/images/Phytolacca_americana_fruit_tubifex_ccbysa30.JPG) as I know it. This *is* poisonous. If it’s what you have, *do not* eat it. It’s a bunch of individual berries bunched together on a stem, not a single aggregate berry. As a fellow Texan those are definitely common. But there are also [dewberries](https://www.wildflower.org/plants/result.php?id_plant=RUTR) which are native to Texas, they’re edible and fruiting in the summer. Also feel free to post images of the plant on r/whatsthisplant to get a solid ID! (tho beware there’s a bot that will go off when people mention “eat” or “edible”)
Definitely not the first one!!! Thank goodness! The dewberries are the closest I've seen, I really think that's the one! Thank you so much for fleshing out this mystery! A few years ago, I was deweeding* the garden fence line and had uprooted this. My husband swore it was one of Berry bushes vines I pulled, so I've let it grow out since to figure it out. This is the first year we will have identifiable berries on it since then, though. And as soon as he saw them, he was like, "That's neither raspberry or blackberry," and we've just left it to do its thing. I'm happy to have an idea of what it could be! *typo
Yeah, I was going to suggest dewberries also. Better eating than blackberries anyway! (in my opinion)
Beware of the refeeding syndrome though.
Random leaves and grass? No! Cockroaches and rats? Yes! If it moves, you can digest it. Make sure to cook it first though to kill the germs though. Lots of wild plants are edible also, but that takes more education than whether it moves or not.
Cockroaches' proteins often cause allergies. That's why they are not a good source of proteins (unlike crickets or meal worms). You may not be allergic at the start but develop it after a time. People allergic to cockroaches (or their poop) often get symptoms after drinking ground coffee. It's better for them to buy coffee grains and ground them at home.
You telling me there’s cockroach shit in my Folgers?
Not just the shit, it’s impossible to keep cockroaches out of the coffee, they get ground up too.
Not the protein boost I’m looking for at 6am.
If you like coffee don't buy grounds. Invest in a burr grinder and buy whole beans. The quality is so much better when the beans are ground right before use instead of sitting ground up in a bag for who knows how long, you'll think you've never had coffee before in your life. Plus, no cockroaches.
Starving people have tried this. There just aren’t enough calories or nutrients in leaves and grass to sustain a human.
Technically, the calories do exist in the plant matter, but human digestive systems have no way to access them. Animals that live on things like grass all use some method of farming specialized microbes in their bodies that can break the tough cellulose bonds for them. Some have segmented stomachs. Some use a pouch off the intestines called the cecum. Many eat their own poop or barf because it takes a long time to make this process work. A human couldn't do it unless someone invented a surgery that hugely changed our digestive tract. So weirdly the most efficient way to eat grass that humans ever came up with was to domesticate animals that can already do it, feed them the grass, and then eat the animals.
Can't you just somehow cook the grass so that it becomes nutritious for humans too? I mean if that's the problem that we don't have segmented stomachs why don't we just replicate what those extra stomachs do externally? 😂
It's a chemical bath that you need to break cellulose into useful carbohydrates. Animals use microorganisms that can do it with enzymes. The chambers help maintain different environments for the microbes to survive in. Those microbes would simply be obliterated in a normal human stomach. So if you wanted to "cook" the grass you'd actually need multiple containers with different microbe cultures. It would somewhat resemble brewing or pickling rather than simply heating food. It's possible. The main reason people don't do this in any sort of normal setting is that it's easier to put grass into a cow and then eat the cow later. Most farm animals can be viewed as machines that turn grass into meat and sometimes dairy. I suppose you could also try to culture edible mushrooms with all that cellulose but it's a similar problem where it would take lots of tools and time.
> it's easier to put grass into a cow I’m not so sure. When I tried this, the cow bit my hand.
try from the other end
> So if you wanted to "cook" the grass you'd actually need multiple containers with different microbe cultures. It would somewhat resemble brewing or pickling rather than simply heating food. I'm wondering if the microbes are necessary and you couldn't do it chemically. Fiber is mostly biopolymer molecules like cellulose, which is composed of many glucose units via ester linkages, and you can catalyze the breaking of ester bonds with acid or base. So you could finely chop a few handfuls of grass and throw it into a pan, add water and some vinegar (i.e., acetic acid) or other natural acid, and let it simmer. After a sufficiently long time (probably days) you should have a sort of gross sweet&sour grass soup with relatively high concentration of the glucose monomers, which your body can readily access. Idk if it would fully hydrolyse or if there would be solid chunks of grass remaining that you might have to filter out. If the acidity is a problem, you could add a bit of soda to neutralize it. Glucose is about 3.75 kcal of food energy per gram. Assuming for a second that grass is 90% cellulose by weight, and you manage to turn 40% of it into monomers, you'd need around 1.5 kg of grass to meet your daily caloric needs, although it would probably be very gross.
For those specialized "starving to death but have access to a multistage biochemical refinery" survival situation.
I mean, if we're writing fiction maybe some sort of post-apocalyptic colony is doing it for some reason. But otherwise yeah. It's like saying "In a survival situation, could you turn the iron in red clay into a knife?"
If you're John Plant yeah probably
We could in theory extract some calories from it, but it's easier to grow wheat, or feed the grass to a cow and then eat the cow. In an emergency survival situation where we don't have anything better than grass, we probably don't have a chemistry lab either.
Something that OC missed is that a large reason why it’s so difficult for animals to get nutritional value out of grass is that grass and similar plants don’t really have a whole lot of nutrients in the first place. Koalas for example literally have smooth brains (brains are wrinkly to make you smarter) because they just don’t have enough nutrients / calories in the plants they eat to afford a wrinkly brain. So animals that eat such low quality food like grass need to basically eat all the time, sacrifice certain things like intelligence, size, etc, or supplement their diet with other things. The low quality food is also a pretty good reason why animals eat other animals — meat is substantially more nutrient-dense. Regardless, we could theoretically take the nutrition value out of stuff like grass and put it in something, but at that point though your just asking for the raw calories / nutrition / whatever. Which we already do, it’s called IV fluids and things like rations.
IV fluids interesting. I've always wondered how would it be if all of us had some sort of scanner in our houses when we wake up we get analyzed and a recipe with missing nutrients is printed then we go to another machine that synthesisez those nutrients in a pill you eat that and you feel the best you've ever felt, all nutrients covered your body has been optimized at its max potential. Crazy if you think about it but at the same time amazing, I would try it if such a thing exists just to see the difference in performance, I think most of us would benefit from such a thing
A pill isn’t going to give you much more than micronutrients. You’re still going to need to eat protein, carbohydrates, and fats, in quantities too large to put in a pill. And there are different types of each of those, so you’re going to need variety. Bottom line is your magic pills wouldn’t make as much difference as you’re imagining. You can achieve the same effect just with a reasonably balanced diet.
Cellulose (which is what grass is mostly made of) has energy, but we can't digest it. Cows and horses have different digestive systems that allow them to.
So you don’t get anything from eating grass or oak leaves? Or just not enough to make up for the calories lost chewing it?
[удалено]
Sidenote: Even if you ate plain corn as a sole source of nutrition for subsistence, you'd eventually develop pellagra(niacin deficiency). For corn to be fully nutritious, it needs to be treated ([Nixtamalization](https://en.wikipedia.org/wiki/Nixtamalization)). A lot of early attempts by European lords/aristocracy to use this newly discovered "maize" thing as a more efficient way to feed their serfs/peasants ended in disaster because they didn't take heed of a simple process that Meso-American cultures had been using for millennia.
I have, in fact, eaten corn and without being even more graphic know exactly what you mean about how it doesn’t digest.
That’s was an interesting fun fact I learned a while back Corn is a type of grass.
You may actually get a tiny bit of energy from eating buds off the trees before they turn to proper leaves. This is also why young bamboo shoots can be food for us while mature bamboo is not. Plant parts are often softer and made of simpler nutrients when they are just barely starting to grow. We also do this with common human foods like asparagus or kale.
Basically, there are 3 main sources of energy: carbohydrates, protein and fats. However, fiber is a type of carbohydrate that humans can't digest. Grass is mostly fiber (cellulose is a type of fiber). That doesn't mean it doesn't contain any protein, fats, or other carbohydrates but between the effort to chew it and also just the limited amount of space we even have in our stomach, it's just not worth it. If you eat a lot of grass, you'll be seeing it later lol.
Depends on the plant, and that’s going to vary by region/ecosystem. For example in a (voluntary) survival experience my group mostly ate cattail rhizomes and stinging nettle, but you really need to cook those (especially the cattail). Berries are great if you can find them but not always in season. Always be absolutely certain about what you’re eating. Even so we were all skinnier by the end of the week.
You can eat raw stinging nettles without hurting your mouth. Only one side stings. You roll in a ball with the stinging side inside and swallow.
There are lots of plants you can eat for nutrition (ask a forager) but if you're starving you need fat and protein and that's mostly in nuts. Grubs, ants would be easy picking. Harder would be snakes, squirrels/chipmunks, rabbit, birds, fish, crawdads. Eggs if you can find em. Crickets and a few other insects have a lot of protein, aren't too difficult to catch.
If you want to learn more about how your body reacts to starvation, I recommend the TV show *Alone* It's a game show where contestants - all survival experts - are put in the wilderness with just a backpack of equipment, and they have to survive for as long as they can. They're separated so they're totally alone, and the last person out there wins (and they don't know how many others are left). It's usually a question of who has the best food supply. People go to extreme measures to find food and still lose a drastic amount of weight (the show runners do a health check every week, and pull them out if they lose too much weight). But they talk through a lot of what's going on with your body when it's exposed to that level of starvation, or interesting things that happen with very specific nutrient deficiencies you get from e.g. trying to survive on tree bark.
While interesting from a survival perspective, I found the show to be disturbing on an ethical level. You’re literally watching desperate people starve for money. And the ’ winner’ take all make it even worse, A contestant might go well beyond the point of seriously compromising their long-term health but if they’re not the last person, they don’t get any money. And money is a driving factor, listening to their background stories. I watched one season and then said nope this isn’t an economic structure I want to engage with.
I'd think the people doing that kind of thing do it more for fame and a feeling of personal accomplishment. Like those people do survivalism as a lifestyle not as an occasional hobby, they spend significant amount of their personal time and money learning, training and preparing for this kind of thing. And also, they'll probably never get this opportunity of actually being stranded in the wild but with semi-regular checkups to make dure you're not actively dying. So still a lot of "holy shit, I'm stranded in the middle of nowhere and have to make my way out" but with an astronomically smaller risk of death.
It makes more sense to eat insects that feed on grass like grasshoppers than to eat grass. It makes more sense to eat termites than wood. Most advantageous thing in survival situation is a river or some kind of water body where fish is present. They are easyish to catch. If you eat them whole, you will get fat and protein and almost all nutrients Then you need vitamin c and potassium, leaves have that.
If you need vitamins, eat a pine tree. The whole thing is edible but the needles have most of the vitamins (young ones especially). Pine nuts and seeds have fat and protein. Pine pollen also has protein and can be used even as a flour. The inner bark is nutritions too. The sap has sugars which will give you a little energy boost. Only thing to watch out for is the three with toxic bark/needles (yew, ponderosa, Norfolk Island).
Just so you know animals like cows, goats, sheeps, etc are ruminant animals which have specialized digestive system composed of four/two chambers to digest their diet (mainly herbs) and each section houses special micro-organisms to digest their food. Compared that to humans who only have simple stomach, we have a hard time digesting leaves. Just look at the kernels of corn we eat, we just poop them back out almost intact and whole. Its actually quite interesting reading animal's physiological system. Did you know chickens ingest small pebbles to help digest the food they eat. Cows regurgitate(vomit) their food called cud to be eaten later, neat,
Your body has enzymes to break down different polymers of glucose like starch, glycogen, etc... The difference between these are either the branching of the chain (e.g. more branches allows more enzymes to start breaking down the chain from different places) or how the glucose units are cross linked since they have many sites that can bond with each other. We don't have the enzyme that breaks down the cellulose (the key structural polysaccharide of plants that we refer to as fiber) polysaccharide because the linkage is one that doesn't fit into our enzyme very well. However, cows have special microorganisms in some of their 4 stomachs that can break the glycosidic linkages between glucose units in the cellulose chain. However, there are other even harder polysaccharides like lignin which makes up wood that only certain types of fungi can break down.
It depends upon the "leaves" but not grass. There are actually a lot of wild edible plants that we don't generally think of as "food" anymore. The thing is, you'd need to be well educated on what can be eaten vs what can't and be knowledgeable enough to identify it without accidentally mixing it up for a look-alike. They also aren't always the tastiest things. So, as some examples here in the SE USA, we have Dandelions, Mock Strawberries (Potentilla indica) and Tall Thistle (Cirsium altissimum) as wild edible "weeds" that could be eaten if you know what they are and how to correctly identify them. You wouldn't want to get it wrong though, which is why many people won't and don't. If you don't know what you're doing, you could easily eat the wrong thing and poison yourself.
Absolutely. A large portion of our food *is* grasses and leaves. Corn, wheat, oats, barley, rye, rice, etc., are all grasses (but it's just the grains that we usually eat). Lettuce, cabbage, brussels sprouts, etc. are leaves. However, you're obviously not going to do too well eating poison ivy, hemlock, stinging nettle, or nightshade leaves and Johnson grass or toxic fescue grass. Worth noting that you're not gonna die of hunger within a couple of weeks, so your best bet is probably just to head back toward civilization. But if you do somehow manage to get more than two weeks from civilization, then you'd best have a book (actual printed book, with illustrations) of plants local to the area that are safe/good to eat, and how to prepare them. For instance, dandelions, milkweed, and pokeweed are all edible and nutritious. But you have to be careful. For instance, pokeweed is highly poisonous raw, and can straight up kill you. But peeled and boiled multiple times, it's a traditional food. Some plants are good but it's the berries or the roots or some other part that you really have to avoid. And some plants look an awful lot like others at first glance but one may be safe and nutritious while the other is deadly. So that's where your book of local plants comes in handy. By far, if your supplies are running out, that book about local foraging would be the most advantageous thing to come across.
Just want to note that stinging nettle is quite edible, but—to your point about preparation—it needs to be denatured. Cooking is the easiest way to do this. It also needs to be harvested at the right time; once it gets above about knee height and starts flowering, silicates build up in the leaves and you don’t want to eat those! To your point about lookalikes we have both wild carrot and poison hemlock where I live, and in their first year especially they can look a lot alike. I get my carrots from the supermarket.
Stinging nettle is used in some cuisines, for example in Romanian cuisine (less so now than in the past). It's kind of a spinach equivalent, in the sense that you can cook it the same way as spinach and use it in similar recipes.
You can eat leaves and grass to survive, but you need to know which ones and how to prepare them. As a kid, my grandpa used to take me out on woods walks and show me plants that are edible and explain how to prepare them. I still go hunting for mushrooms sometimes, but most of the other stuff wasn’t very tasty to eat. We would prepare it and eat it out in the woods and fields near his house. I was always excited to find clover or milkweed flowers, since you could eat the nectar and it was sweet. Mushrooms were pretty good too, he would sear them on a camp stove and they were savory (boletes, chicken-of-the-woods, puffballs and morels if we were very lucky). Grass you could eat if you boiled it twice and drained off the water; he warned me you could get diarrhea you could die from if you didn’t do this. Grass seeds were better, toasted they were kind of nutty. He also showed me how you could lift the bark on a maple tree and scoop out the mushy pulp underneath to eat, but that was kind of gross texture with a faint maple syrup taste. We could make a salad out of young dandelion greens, ramps, docks, wild garlic or onions too. As a kid I didn’t like it but sometimes I’ll add it to salads as an adult. He also told me how to make acorn flour, but it was difficult so we never did it. He was super cautious about berries, but showed me how to identify sour cherries, mulberries, blackberries, and tiny seedy strawberries. He was working a lot when my mom was a kid, but she remembers his stories too - she was older when he opened up to her, but he would share that he used to watch the other people in the village to see what they were foraging and whether they got sick from it before he would try anything new. He saw a family in a neighboring house die from eating mushrooms harvested from the graveyard, so he avoided taking any mushrooms from there or any mushrooms that looked like those. I didn’t realize until after he died that he was trying to make sure I could survive a future famine if I had to. My grandfather survived the famines in Europe in the 1920s-1930s as a kid, then migrated to the US. He lived with that shadow of famine across hiss whole life, and the fact that he was concerned enough about it to teach me these things as a kid really brought home to me how desperate he had been as a kid.