I did not get an exact answer when I looked this up myself. The best answer that was given was "because we're carbon-based lifeforms", which doesn't really help me understand anything at all.
It takes more energy to hypothetically "digest" stuff like copper, diamond, rocks, etc. than an organism would gain from said digestion. Organisms still use energy to digest organic matter, but it's a net positive, they gain more from it than they burn digesting it.
Why does it take too much energy to extract energy from it?
Most materials molecular bonds are too strong and the energy it takes to break these bonds, is more than that of the material itself
This doesn't quite answer it for me.
1) Why can't we eat Uranium or Plutonium, if they are naturally decaying materials, wouldn't their bonds (do elements have bonds?) be weak?
2) How about coal or petroleum? Those are carbon based and high enough in energy to power our society, why can't we consume them for calories?
For uranium and plutonium, their ability to release neutrons and other particles requires a high degree of repair capacity by the organism. You need a lot of molecular defenses to ensure you not only successfully capture the energy and use it without damage to your internal cellular structure, but also to ensure the transformed atoms that make up your molecular structure are excreted fast enough. Turning carbon into nitrogen is a horrible scenario if it happens enough times, especially to DNA.
For petrochemicals, these are highly concentration and not generally soluble in water. They also rapidly react to DNA substrates, hence their carcinogenicity. Overcoming these, straight carbon-hydrogen bonds are actually quite difficult to break. See the case of plastic; only special oxidative enzymes can create the free radicals that can break them down. These enzymes only evolved much later in the advanced basidiomycetes of the fungal kingdom to break down the lignin found in trees.
Good answer, but worth mentioning a huge factor is these materials are extremely rare from the perspective of life. Life on Earth simply hasn't had the appropriate exposure to these materials to pressure an evolution into consuming them. If the oceans were instead petrochemicals (ignoring the fact life as we know it wouldn't have even begun) then you can be sure life would find a way to consume it, or utilise it in a metabolic process.
Note that we've changed that, introducing a bunch of energy-dense plastics all over, giving evolution a chance to work on it. And it appears to have already started - https://en.m.wikipedia.org/wiki/Ideonella_sakaiensis is a bacteria that eats PET plastic.
Good point, definitely the concentration of high-energy compounds in only specific regions of the world reduces the probability of exposure and use. It would be interesting to see what sort of microbial madness would arise from planets with oceans of specific compounds.
Life on Earth simply hasn't had the appropriate exposure to these materials to pressure an evolution into consuming them.
Well, not quite true. There's some fungi that can at least do something with ionizing radiation out there. It's not clear if they actually derive energy from it though.
This is the type of ELI5 answers I am amazed of. I understood the answer without understanding majority of the words!
Specialized bacteria do eat petrochemicals.
Yes, of course. But it’s not fundamentally something that a large swath of living organisms can metabolize as a major source of energy, as OP is asking. It’s a subset of metabolism for Pseudomonads et al. microorganisms that adapted to the presence of petrochemicals over time or already had the machinery to do it from metabolizing similar compounds in their environment.
And even then it tends to have to be fairly dilute for long term survival. I think there’s only a handful of extremophiles that can straight up consume and live in gasoline, and even then they need to have some moisture in the environment.
I guess you could make up some kind of "life" that feeds on radioactivity. You absorb the high energy neutron, use the energy to do something and release a low energy neutron.
Car-Sin-Oh-Jeni-City
So, elements don't really have bonds, molecules and materials have bonds. Some elements form molecules, such as as Hydrogen forming H2. Metalic elements form a different type of bonds.
When we say an element is decaying, this actually has nothing to do with bonds. It means that the actual atoma are changing, normally by emitting some sort of particle and/or amount of energy.
This energy is called radiation, and our bodies cannot capture or use it, however, some organisms, such as specific mushrooms and some bacteria can harness the radiation, much as a plant can harness the power of the sun.
For coal and petrol, the issue is how much energy is required to start braking the bonds, and the fact it requires oxygen to do so. Even though burning fuel releases energy, you need to pump a lot of energy into it to get it out. This is what a fire starter or a spark plug is for.
Why can't we eat Uranium or Plutonium, if they are naturally decaying materials, wouldn't their bonds (do elements have bonds?) be weak?
Uranium or Plutonium are elements. There are no bonds there to break, they just unstable, and "fracture" into two smaller atoms, while radioactive radiation happens.
How about coal or petroleum? Those are carbon based and high enough in energy to power our society, why can't we consume them for calories?
This answer partially answers the first one as well. Our system is incredibly complex, we can't even digest all "edible" molecules all the time. Gluten sensitivity is triggered by a protein, gluten. Lactose is a sugar, and a considerable amount of people can't eat it.
Starch is made from glucose (a sugar type), and we can eat it, and we get energy from it. Cellulose is made out of the same glucose, but we can't digest it at all.
Without getting too deep into the chemistry part, you need a really specific enzyme to break down a molecule, and a lot of interconnected steps afterwards, that allows you to make energy out of it. During evolution we got some of the enzymes as given, others were only active when we were babies (lactase to digest lactose), and consuming milk in our adult life allowed some populations to keep the lactase enzyme active for our whole life, while other groups naturally lost this enzyme as they aged. So our diet also modified it.
But to go back, baaaaack to find a simple answer: animals had no real access to coal and petroleum during any point of the Earth's history. So these materials are as foreign to our bodies as it comes. Some bacteria or fungi can break them down and get energy from it, but as we humans does not originate from those bacteria or fungi, we never got "access" to those enzymes, we never got to know those molecules.
(As a side note - simpler life forms like bacteria and fungi use comparatively a lot less energy, as they are small and simple. They are okay with smaller amounts of energy, but every creature that "eats" molecules made up by other creatures, they get energy a simpler way, the molecule is more refined, energy dense, and also - unified. We can't eat the numerous plants goats eat, but we can eat goats. They made the energy-transformation for us already. A parallel to this exists on the molecular level too)
Eating is about more than calories. The food has to have either the building blocks you need for making cells and carrying out bodily processes, or it has to have something that your body uses to make its own building blocks. For example, we need fat for every single cell in the body. If we don't eat enough fat, we die. But if we eat a lot of sugar, we can get by with less fat, because the liver will create lipids from the sugars. You may get calories from something like petroleum products, but they're also irritants, hard to digest, and could stop your body from breaking other things down as they're covered in oil. People sometimes take a small amount of mineral oil to clear constipation, because oils just go through and bring other stuff along for the ride.
So if we choose strictly for calories instead of nutrients, we would choose something that tastes good and is easy to drink over something that's painful to drink, doesn't help us, and gives us diarrhea. Thus we have soft drinks and juices and such instead of downing a shot of gas.
Plutonium is a bit spicy and doesn't taste very nice.
There actually are many microbes that break down rocks and other “non macronutrients” (fats carbs proteins) like this (https://journals.asm.org/doi/10.1128/AEM.00657-10) and they are everywhere. The problem is such energy extraction is limited even if abundant (the redox gradient is a fraction of the oxygen gradient that aerobic organisms enjoy), so organisms that do this are limited to unicellular. There are also bacteria that metabolize uranium (Geobacter uraniireducens) and since plutonium is practically nonexistent in nature, I doubt any exist to metabolize it. If you read studies about these guys you’ll realize eating uranium comes with major adaptations (like tolerating radiation) so again, the only life forms that can profit from such meager-albeit plentiful-resources are single celled. As for coal and petroleum, there are Nocardia and various types of Bacillus that can metabolize it. In each case, there are organisms that evolved SPECIALIZED ENZYMES AND METABOLIC CHAINS TO MAXIMIZE ENERGY EXTRACTION. We lack such enzymes. While we could ingest enzymes to help, this is nowhere near as efficient as producing them from our DNA.
A possible answer to both of your questions is accessability.
Where is uranium, plutonium, oil, and coal located? How easy is it to get to them?
Where is sun light, plants, decaying matter? How easy is it to get to them?
Which of these sources of energy are accessible by using the least amount of energy possible?
1) Yes, elements have bonds. For example, Nitrogen, N, is naturally diatomic and will form a molecule of N2. The two nitrogen atoms are bound together. This form, N2, is the type that we breathe in the air.
To answer that, there are some organisms that do utilize radioactive energy in order to grow and live.
But most don't. That's for a couple of different reasons. It's unstable. Not just the energy amount but also the effects on DNA/reproduction. Yeah, they provide energy that some organisms can use, but that same energy also tends to damage the genetic material necessary to reproduce and create new organisms.
2) Humans, we, can't consume them because our digestive system just isn't designed for that. Other organisms can and do. They have evolved digestive systems that can utilize those sources of energy.
Humans just don't have that niche.
Coal and petroleum didn't exist when the metabolic processes of life were evolving. If the early bacteria were swimming in a sea of hydrocarbons--like what exists on Titan--they very well might have evolved to eat petrochemicals. But on Earth, those hydrocarbons came from hundreds of millions of years of creatures living and dying and becoming strata in the deep earth.
Uranium or Plutonium? Way too rare to even consider. And Radiation would destroy the organism from within even if it could somehow capture the energy.
And why we can't consume petrol or coal and the like? because when we say our body "burns" carbs or fat, it's not doing it in the same way it would burn in the free air. What your body does is more dismantle it bit by bit, capturing the energy in other chemicals (ATP mostly) as useful chemical energy instead of the relatively useless thermal energy normal burning would. The net reaction is the same but it's a whole lot of steps to do this. You can't just throw in another chemical and expect the same steps to work.
1) some elements occur as molecules and some as atoms. Nitrogen and Oxygen are two common elements that normally occur as molecules (N2 and O2). Uranium and Plutonium usually occur as atoms so there are no molecular bonds to break. The natural radioactive decay involves the release of subatomic particles that can pass through or close by other atoms or molecules without interacting with them. When they do interact the result can be something a living organism would be better without, like radiation poisoning.
2)There are bacteria that can use petroleum as a food source. Bacteria is good at adapting, they mutate relatively frequently and reproduce quickly - increasing the chance of a random mutation being beneficial. This doesn't scale well to more complex organisms.
This next bit is at best an educated guess:
In theory, it could be possible to use chemical reactions to convert petroleum to something people can digest but petroleum contains hundreds of thousand of different chemicals. After the purification and chemical transformations it would be absurdly expensive but there are petroleum products are used in some food products - gum contains petroleum waxes.
1) Nuclear decay is not a chemical reaction. Regardless, some fungi can use radiation as an energy source. This is like asking why we can't just absorb sunlight for energy (plants can though).
2) Some bacteria can. We don't have the enzymes that would allows us to do the same.
Note that in either case the question isn't just whether you could get energy from it, it's also whether you could get enough efficiently enough. It takes a fair bit of energy for humans to be walking around.
Natural nuclear decay doesn't really fit the bill for humans, but works great for fungi that are constantly exposed to it.
Petroleum was late to the scene and is formed underground. You don't really find a lot of life where petroleum happens. It's unlikely that anything would have the selective pressure to mutate to consume it far enough back in the evolutionary timeline for it to impact humans.
Uranium will decay and produce smaller nuclei and release some energy and ionizing radiation. The latter is inherently bad for you as it causes cancer and basically destroys chemical bonds. One reason why this would be bad. But physically, to break the nucleus you still need to exert energy, but you're right, once the body would break it there's more energy gained. However, most of that energy will also be heat and your body can't just take heat and turn that into usable energy. Organism digest food to turn that into chemicals that they can easily further break down in cycles that release energy just as needed.
For petroleum I'm not entirely sure of the chemical composition, but if those are mainly long carbon chains those could be digestible. Plant oils are edible, fatty acids come to mind and these are I think used in fatty acid oxidation. AFAIK mineral oil isn't digestible though.
Some microbes can live off petroleum products and there's a mold growing in the Chernobyl reactor that appears to be living off radiation and nitrogen from the air. But it's easier for fast mutating/adapting species like microbes to adjust to that
Because metabolism isn't just "consume, burn, get calories."
For calories burned (catabolism), your body breaks down large molecules into glucose, and then further breaks that glucose down into pyruvate. Your body NEEDS pyruvate, a specific chemical (C₃H₃O₃⁻). It is not just raw energy. This pyruvate then binds to another specific molecule called Acetyl-CoA to then undergo an even more complex reaction called the TCA/Krebs cycle.
All of your aerobic cellular metabolism NEEDS to get pyruvate in order to survive.
Tldr: the body burning calories is a gross oversimplification. You can burn chemicals to harness the energy stored in their bonds, but your body needs a very specific molecule.
Both are probably easiest answered by that they are not around u less you dig quite a bit. Carbohydrates and fats however, are. I suppose all comes from the way plants evolved.
All of those things are poisonous. Putting that aside, not only can you eat all of these things, you can find out the calorie content
So, you Are powered by fire, every Cell do bit of fire, all the time. You dont get energy from food, but Fuel. Cells get the oxygen And somesort of hydrocarbon from blood, breaks weak Bonds with hemoglobin And hydrogen And combine them. Molecular fire- energy And more energy than you put in it, if you set coal on fire it Will Burn. So it Worth to do that, Plant was here before And had to make their own oxygen. Petroleum Is just old Plants, you know oil, Is kinda the same like butter which just like fat which kinda like sugar which Is similar to protein, all Is just some kind of hydrocarbon. Petroleum Is dirty af And you wouldnt put that in car without refining. Radioactive material can't do combustion of oxygen and carbon So your body can't use it. Furthermore the radiation mix up atoms in dna causing cells death or cancer growth.
1) Because there wasn't a lot of refined Uranium sitting around while we evolved.
2) Because there wasn't a lot of fossil fuels sitting around while we evolved.
Given enough time, I am confident that some biological process will evolve to digest the energy in these materials.
There simply are no convenient energy-releasing reactions with naturally occurring reagents for those compounds.
It's the same reason you cannot burn water or sand. Metabolism is basically just a fancy form of fire and if something has already been "burned" you can't burn it again. A lot of the stuff you listed can be coaxed into burning, but that requires exotic reagents or highly energetic conditions for the reaction to occur, which require more energy to create than what you get out of the reaction in the end.
The physical/chemical structure of those items is very stable.
The reason that diamonds are so hard is because the carbon atoms are linked in a very stable way. Because the carbon atoms are linked in a very stable way, it would require a lot of energy to break those bonds.
Same way with things like copper or rock or clay (although there are some organisms that do eat those things, but they are not super common).
Kinda like, did you know that when stars begin to fuse iron in their core they are basically at the end of their main sequence life, because iron is the first element in the solar fusion chain that requires more energy to create than it releases upon creation?
I think you last sentence is not worded right. Creating iron still generates net positive energy. It is the next element after iron that consumes energy to be created.
In addition, iron is not the first element to consume more energy in fusion it is Nickel-56 which is made from Iron-52. It is Nickel that is at the end of the fusion process not iron. Then, Nickel-56 decays to Iron-56, but that takes 6 days to cobalt-56 which decays in 77 days to iron-56. The supernova occurs about 1 day after silicon burning starts, so those decays don't really happen in the star. Fun fact, that decay chain is what creates the characteristic light curve of a core collapse supernova.
No, fusing silicon to iron does not produce the stable energy output needed for the core to push against its collapse, Iron is a net negative in energy, it costs more energy to fuse than it provides
Fe-52 + He4 -> Ni-56 + γ, 8MeV
It is exothermic. Every alpha process step from Si28 up to Sn100 is exothermic, but it stops at Ni56 due to photodisintegration winning at the temperatures in a massive stars core.
I can agree on not calling it stable energy output, since the energy from Silicon burning is so low that it only takes a day to convert the entire core. Someone who does core collapse simulations would have to comment on whether that stops the collapse for a day or just slows it down.
The chemical bonds in something like sugar can be broken with a little energy then they release a lot of energy, like striking a match or turning a car key that starts the engine. The chemical bonds in something like clay are harder to unlock and when you do there is not enough energy inside to be worth it.
Imagine eating wood, like a fire does. Lots of chemical energy, leaving behind ash, which is mostly carbon.
Now, try eating carbon. All the energy is gone and it's in its lowest energy state.
Most things like rocks and natural copper and diamonds are in that state after thousands of millions of years in which it could decay, so it's probably in a very low energy state.
The other problem is the cycle - humans eat plants and exhale CO2. That CO2 is used by plants as the material to actually make stems and leaves and such. That cycle doesn't exist for copper, which means that the bacteria that breaks copper into something lower energy would run out very quickly.
ash, which is mostly carbon.
Specifically, there's a lot of calcium carbonate. Not elemental carbon dust, which has lots of energy to give you in an oxygen atmosphere.
People are mainly explaining how but not the basic reason why.
See all potential food (be it rocks, be it actual food) as batteries that were once charged a looooong time ago. We can survive on food like you can power a lamp on batteries. But batteries go bad over time, so basically all batteries that have been around for so long have been depleted. Sure, there'll remain the odd battery with a bit of charge left, but nothing too impressive.
Plants however are charging stations, that constantly replenish biological batteries with energy from the sun. It shouldn't be too surprising that therefore most beings that require food to function are depending on plant batteries, as they're just the most plentiful. Then on top of that we have predators that eat animal batteries (fat), just because there are so many animals - because there are so many plants.
It's important though: basically anything that you can squeeze out some energy from will be used by something. There are plenty of things that eat the weirdest shit (like a fungus that 'eats' radioactivity).
It's just that the things that eat that weird food can only be found in places where that weird food is, and that's why you will never find them in huge amounts in other places without the weird food they eat.
The chemical bonds in metals, diamonds etc are very stable, living organisms don’t have a way to extract energy from those bonds. Complex organic molecules like proteins, carbs etc have lots of potential chemical energy stored in their bonds. Living organisms convert those complex molecules into simple molecules with very stable bonds (think CO2) and use the resulting energy to do work in the body.
It's a matter of basic chemistry (pun intended). The way our bodies are composed, it's takes less energy to pull apart molecules from food we consume (other organic compounds). If our bodies interacted chemically with metals or atoms that can easily pull them apart to steal their "nutrients", it would be easier to consume metals.
I'm oversimplifying, but it's basically the energy required to turn the molecules into different molecules that contain energy our bodies can use.
Man, so many of these answers are way beyond a 5 year old.
To get energy from something, you gotta open it. It's a lot easier to open a lid held on with a weak magnet than one that is held on with glue
First, the thing to understand is where the calories in food are stored before you eat it. The calories are stored in the bonds between the components of the food.
The second thing to understand is that the digestion system breaks those bonds and provides you with energy.
A rock has much stronger bonds than typical food and we do not process the enzymes and digestive system to liberate the energy.
In some ways plants already do this ? They “eat” photons and minerals and produces organic material from it.
Say I have 2 towers. One is made of sand, and the other is made of reinforced concrete with rebar. I need building materials. Which tower would take more energy for me to knock over?
To take it to the next step, this is all about chemical stability. The reason you acknowledge that it is mostly metallic or lattice materials, is because these structures are very sound. The way your body works (oversimplification) is it adds phosphate groups to glucose. This is a rigid molecule, and these phosphates make it unstable, allowing it to be cleaved later.
Metals are so uniform and flexible that this won't work on them, and lattice structures are too strong. Your body has to put energy in to get energy out. To maximize yields, it wants things that are easy to break down.
Energy is released when bonds are formed, and breaking bonds requires energy.
To be energetically beneficial, you need to form a bond that is stronger than the one you break. If something already has very strong bonds, you end up with a situation where forming a stronger bond is difficult or impossible.
Its also not just a question of energy.
We need certain stuff to live. Just diamond would not allow the body to replenish electrolytes, iron, or other mineral we need.
Its also much harder to get by so why would evolution favor the digestion of diamond over plants or meat that is much more easily accessible.
There's a point where the actual answer to your questions is: You need to go learn more about biology and chemistry.
You can't realistically expect anyone, even a scientist (Hi!) to be able to just simplify multiple entire fields of scientific study into a few sentences.
The answer is that you don't understand some fundamental underlying scientific concepts and you're unlikely to get an answer that makes sense to you until you learn more.
This: energy balance. Same reason stars don’t fuse elements heavier than iron.
Yes and No. Large enough stars can and will fuse beyond Iron, theres a couple different forms of fusion that can occur and its not well understood, but they can, in small quantities, Iron is just the beginning of the end though. The majority of heavier elements than iron however are made in supernovae and killanovae
Very cool, thank you. I read a passage years ago that still chills me. I have not been able to find it again. It started by saying that stars fuse hydrogen for so many billions of years, then helium for a slightly smaller number of billions, then lithium… and got to iron by saying that once they start fusing iron they have only a few hours left. I literally shivered. The insanity of the scaling.
Unless it's celery that has net negative
The vast majority of energy transfer reactions in living organisms occur at ambient conditions or near ambient conditions. They also occur in water, so most energy-producing substrates need to be at least somewhat soluble in water.
The energy required to overcome the energetic barrier to move electrons in something like copper or graphite is very high, so it’s not energetically favorable for most organisms to use these substrates.
They also are not universally abundant in solution, versus protocarbohydrates, amino acids and nucleic acids were more abundant in the soup of life in early oceans. You also need a very prevalent electron acceptor, which oxygen ended up satisfying after the oceans started spewing it after the evolution of photosynthesis, and carbon-based molecules are very good at reacting with oxygen.
The counterpoint is that if the world was made up of mostly oceans of ammonia, you’d likely see organisms be able to extract energy from lithium, which is soluble in ammonia.
Fats, carbohydrates, and other sources of fuel for humans are basically a series of atoms bonded together. When you create those links, you use up some energy. When you break those bonds, some energy is released that your body can then use. Raw elements like copper don't have these links, and many other chemicals are either too stable/don't have enough energy in their bonds to be worth breaking apart or are damaging to the human body.
You can think of another hydrocarbon that we use for fuel: gasoline. When you apply heat and oxygen to gasoline vapors, the result is a lot more heat, water, and carbon dioxide. We can then use those expanding gasses to push a car. Our bodies are similar.
instructions unclear, got thirsty, drank gasoline
Do not, I repeat, do not try to light a fart!
For an organism to extract energy, there has to be more energy on the other side of the change the organism makes on something.
Copper in ore, diamond, most rocks, and most clay are "stable," meaning when you put energy into it to change it, the energy you get back out is less than you put in.
Some animals and plants do break down things like that to get rare-element nutrients (eating clay, in particular, is a thing, because it's soft so the rare elements might not be locked behind so many chemical changes as to make extracting them too expensive). But they do that by consuming energy from some other chemical reaction to power the extraction.
(One of my favorite examples is nitrogen fixation. So plants do this cool thing where they get nitrogen from the air as N2 molecules and break it down to use the elemental nitrogen in all kinds of things. And doing that is incredibly expensive. It costs like 12 ATP molecules to do one nitrogen fixation reaction, and that process involves, somewhere in the middle, making hydrazine, which is also known as rocket fuel... And then reacting the hydrazine with the next step fast so it doesn't go be rocket fuel inside the plant cell. We suspect plants do this because in Earth's early history, nitrogen fixed into other molecules was abundant and cheap to extract, so life developed a bunch of chemistry that depends on having ample access to nitrogen... Then it nearly ran itself out of nitrogen and couldn't change away from that chemistry faster than it could invent a new way to get nitrogen from the air. And, notably, humans like all other animals need nitrogen for our chemistry too, our bodies can't fixate it from the air, so we have to eat things that did to extract the spare nitrogen from their molecules).
Plants don't do nitrogen fixation, bacteria and archae do. A fair number of plants have root nodule or other adaptations that provide a habitat for nitrogen fixating bacteria where they exchange sugars and other nutrients for nitrogen compounds though.
Well, actually there are. “ Archaea use more diverse energy sources than eukaryotes, ranging from organic compoundssuch as sugars, to ammonia, metal ions or even hydrogen gas.” There are archea that consume methane, as in natural gas.
It's known as chemosynthesis
enzymes are proteins and they're all made of amino acids. We make enzymes (from protein that's eaten, or made from sugar by bacteria in the gut of large herbivores like cows and gorillas) that can break down the bonds in fats, carbs, and proteins in many complicated sequences so that the energy from the breaking covalent bonds doesn't get released only as heat, like when something is burned, but can be transfered into other high energy covalent bonds that we have other enzymes that use them as a general currency like phosphocreatine or ATP to do all the other stuff we have to do in order to be alive.
the first problem with using weird inorganic things like copper, diamond, rock, clay isn't only that they don't have the right covalent bonds, and that no enzymes ever evolved to break down their types of bonds in controlled mechanisms, but that for all of the protein, fat and carbs we can break down we have other proteins or fats inside our bodies and made by our bodies to break down into molecule sized pieces. Something would need to make metals or make minerals to use to dissolve metals and minerals, but we have to settle for making proteins and fats, like in the case of bile for fat digestion, that can effectively break down or solvate the things we eat into individual molecules. Then if something could do it, those building blocks wouldn't necessarily even be useful for building a body if they can't be made into more organized things that catalyze reactions the way amino acids can be made into enzymes. We still need some inorganic things like copper to live because of the way they are involved in making some enzymes work. Look at the back of a multivitamin and see a bunch more or google "elements needed for life" for specific examples.
I had to scroll way too far to see Enzymes name-dropped.
There are life forms that eat those things. There just aren't a lot of environments where that's a viable way to survive. Most life as we know it metabolizes fats and carbs and proteins because they're already available from other living things around them. The bacteria that feed off more exotic substances live in places where the chemicals we're more familiar with aren't as readily available.
Then there's that the more exotic metabolic pathways just don't provide as much energy as what we're familiar with. Organic molecules have a lot of energy stored in them, which their previous owners had been planning to use later until they were removed. Copper isn't as efficient a source of energy. But, look in the right places, where most life as we know it can't thrive because of heat or pressure or whatever else, you'll find the extremophiles that slowly and steadily munch on the stuff that we just don't consider food, be it copper or iron or even arsenic.
The energy required to break certain bonds can be too much. We are also made of fats, carbs, and proteins. Your bones are not made of copper. Plants can “digest” some minerals and clays and rocks in the ground and that creates soil. They also “breathe” in carbon dioxide to get the carbon for their bodies. We then eat the plants or animals that eat plants to get that carbon and the materials the plants “ate” from the clays and soil and rocks.
Organisms extract energy by breaking the bonds in chemicals and using that energy to do something else. Carbon has a nice property that it can bond to up to four things at once. This means it can make long chains of carbons attached to each other and to other things like hydrogen and oxygen. There's lots of CO2 in the air and hydrogen and oxygen in the water, so there are lots of building blocks all around fro making big chains of things with C, H, and O. If you have long chains of molecules with bonds, you can extract the energy out of each link in the chain. Whereas, with the other things you mentioned, there might be one or two bonds you could potentially extract energy from. The carbon chain molecules also have the benefit of being great for building stuff out of.
Takes too much energy to burn and not enough available nutrients
All of the energy our body uses was originally from the sun, captured by a plant, and stored by conversion either by the plant or another animal that eats the plant. Your body essentially reverses the process to release the stored energy. Inorganic things like minerals don't capture and store the sun's energy, so they don't have any energy our bodies can release.
There are, they are called lithotrophs.
Now why exactly chemotrophs (organisms that get energy from chemicals like fats and carbs) and phototrophs (photosynthesizing life) were able to form much more complex life, I am not exactly sure. But I imagine it has to do with the relative abundance of each energy source.
This depends a lot on what you call "life". If you're thinking about animals like us, we rely on fats, proteins, and carbohydrates because they're full of high-energy chemical bonds that our cells can easily use. We need a lot of energy to do what we do.
Even if we could somehow digest things like rock or clay, the amount of energy we'd need to extract anything useful would probably mean we'd spend all our time just eating and not much else.
Bacteria, on the other hand, do exactly that: eat and reproduce.
Many bacteria, which are among the oldest and most diverse life forms on Earth, extract energy from non-organic substances. For example, some bacteria get energy by oxidizing iron, sulfur, or even hydrogen gas. These are called chemolithotrophs.
That said, things like copper or diamonds don’t have chemical energy that life can easily extract... They’re either too stable or not reactive in ways that release useful energy. I guess you could say diamonds are "waste" as they're something all the energy has already been taken out of, kind of like leftovers. Eating diamonds would be like eating something that has been eaten and used for energy many, many times over already -- there's nothing left of it!
Life evolved around carbon because it forms versatile, energy-rich molecules that can be broken down and reused. This energy is what we needed to actually evolve beyond bacteria and become complex clumps of cells which eventually turned into the complex animals you see all around you. We need the highest amounts of energy in order to grow, move, fight, hunt, etc.
So in a way, there are organisms that "eat rock" just not the way we usually think of eating.
Eli5: it's about the energy required vs the energy gained.
Think of a spring loaded mouse trap. It's set, and a little nudge and it triggers, all the energy stored in the spring is released. Put something near it and you can use that rapidly closing spring to do something useful.
Chemicals are sorta like this too. Sugar is a loaded mouse trap. It's got a decent catch, so it's mostly stable. Give it a small kick and the atoms spring apart, the cell can use this to do other things, like snap together two other chemicals.
Sugar is a very strong trap with an easy to trigger but stable latch.
Other chemicals, like plant fiber, have very very stiff latches, so they take a lot of energy to release.
Some, like the metals you mention, are incredibly weak springs and/or very stiff latch. So you spend a lot of effort triggering it, and you don't get much in return. You may even spend more effort releasing the latch than you get from the loaded spring.
There are chemicals in cells that have to be this way, like a lot of proteins, cellulose, etc that are structural. They need to be strong, so you spend lots of energy just assembling them.
Plants manage this by harvesting energy from light, and assembling their materials. They use light to make the sugars too, so they have rapid strong sources of energy when they need it (growth spurts, healing, etc). Plants basically do the hard work of setting the mousetrap spring and latching it.
Animals steal this effort. By eating the plant we hijack the sugar, without having to assemble it ourselves. We get the energy release without having to set it up. The really tough and low energy materials we just discard, it's to much effort for us.
Looking at the different materials you mention, there are a couple different reasons. First and foremost, you need a chemical reaction that releases energy. Reacting carbs, fats, and proteins with oxygen to make water and carbon dioxide releases a good about of energy.
Looking at rock and clay, most rocks are composed of silicate minerals. In some sense you can say those minerals consist of silicon dioxide and various metal oxides. In other words, the elements in rocks and clay are already combined with oxygen, so there isn't really any chemical energy to extract.
With things like diamonds and copper, first an organism would need to have the right enzymes for controlling those chemical reactions And even then, those materials are not common enough for those adaptations to be worth it.
To add to "because carbon based life forms" it is really all about the carbon cycle, and a little bit of chemistry.
Plants take low energy carbon (CO2) and sunlight to make high energy carbon (fats, carbs, proteins) that can later be used to liberate that energy. Importantly this makes more CO2 to start the whole cycle over. This means that life that eats sugar doesn't die out the moment the last sugar molecule is eaten, more is always produced.
Stuff like rock is not renewable and most naturally found chemicals are already in the lowest energy state possible, you can't get blood from a stone.
Elemental metals have energy that can be released when the metals rust, and some microbes live in undersea vents where these metals appear. But because they aren't being constantly produced everywhere these microbes can't live everywhere, they have to live by thier food.
You could imagine copper based life forms that eat metallic copper and use sunlight to unrust it, but how would that life form get more rusted copper? It isnt a gas that passively diffuses around you'd need plants that can move to thier food source which isn't impossible but is a lot harder than having your food automatically float over to you.
There're several explanation that go into details, but there's a simple answer: Because we're all made of mostly the same components and evolved from common ancestors.
We're made of the same building blocks and thus the lowest energy effort is getting those building blocks as close as ready made as possible. Ingesting protein and fat is much more energy efficient than using raw materials, so mostly only extremophiles have had to evolve to do just that.
If our very early ancestors (I'm talking single celled ancestors) had evolved to be chemically different and amino acids had a different composition, then that's what we'd be digesting today.
The purpose of eating is to consume a substance which when the atomic structures are broken or edited release energy. Diamonds would require vast amounts of energy to break the bonds and release no energy as a result. The rest similarly would also release no energy.
Fats and carbohydrates release energy as they are disassembled. That energy powers other reactions in cells to sustain life.
Proteins are not directly used by your body. They are broken down into their amino acids. Our bodies can synthesize some of these acids, but not all of them. So protein is disassembled to harvest them.
Amino acids are the Lego blocks of biology. They snap together to form molecules with interesting properties. For example hemoglobin is a protein - assembled from amino acids. At its center is an iron atom. Hemoglobin can allow the iron atom to oxidize or deoxidize (absorb or release oxygen) on command. So this is how oxygen is transported around the body
Copper and diamonds are elements. So they cannot be broken down to provide energy. Rocks are silicon dioxide primarily. Silicon dioxide is very stable. It takes energy to split it. So trying to "digest" it would rob us of energy.
That's basically it. Carbs power the body. Fats are long term energy storage (harder to break down, but stable in the body as reserve energy). Protein yields amino acids to creat new LEGO blocks.
We also need trace amounts of other minerals like iron. So you'll see fortified foods , like corn flakes with iron. This literally means iron shavings were added. A common science fair presentation was to grind the cereal, then soak it in water with a magnet. After a few days, the iron supplement could be seen as fuzz on the magnet.
So the things any living consume become part of it. You body can digest organic material and trace amount of minerals and use it to build tissues and muscles and fat. Not much of you is made of gold or steel or fluoride. Additionally working area if chemical interactions means you can't really eat pure graphite or diamond (pure carbon materials) or consume fossil fuels for energy. We essentially have very narrow subset of what can be successfully consumed.
I suppose because many hard minerals like the ones you mentioned are very structurally sound and hard to physically break down, I mean have you ever tried to bite a chunk of granite? And even if something could, there would have to be something in that rock or mineral for the organism to use as fuel, and enough of it for it to be worth the energy spent on digesting it. And given that most lifeforms are already made of fats, proteins, and carbs are easy to break down and energy-rich, that's just what they turned to evolving to need. There's really nothing in a chunk of copper or stone that most lifeforms today could use as energy that a plant or animal couldn't offer in a much better, more efficient way
> I mean have you ever tried to bite a chunk of granite?
Yes, actually (and at the time, I was definitely at an age where people are expected to be doing such things, and most certainly not a highschooler, for whom that would be strange or indicative of some kind of larger pathological issue). Didn't go well.
Point being, understood and thank you! /gen
If you believe Chinese theory we do digest energy from foods/substances that aren’t exactly fats/carbs/proteins. Certain roots like ginseng for example would be high in “chi”. Obviously not seen that way from a western perspective but it’s a theory. Regardless it needs to be digestible based on how we evolved - we did not evolve to eat rocks.
Some bacteria can use metal ions for energy, there just isn't enough of this in the environment for human to evolve such ability.
Overall for energy source to work it need to be able to interact with enzymes so it has to be liquid or solvable in water.
Life chooses the easiest path. If it was necessary, then we probably could draw energy from something other than the usual suspects. There is probably a price to pay though. Take the koala for example. It evolved to eat the poisonous eucalyptus because sometime in it's history that was the only viable food source. Eucalyptus is not energy dense. The koala literally just eats and sleeps to conserve energy, even it's brain has shrunk.
your body is a furnace
it breaks down food into usable fuel for that furnace
the energy to break down a burger and acquire calories from it is less than the amount of energy to break down a rock you ate (by accident or on purpose)
and even then the bioavaibility of the nutrients we need from a rock may not be useful for our bodies.
if something isn't useful and cant be broken down we... excrete it.
if you can't excrete it you go to the doctor and have a bad day.
if your gonna eat rocks, make sure they are small. or chew really well
Scaly foot gastropod uses iron, there’s a tree that absorbs nickel, and the bloodworm uses copper. I imagine diamonds don’t get used because there aren’t many places with so many diamonds that life could use it. Rock and clay feels weird because a lot of what makes rocks and clay is in life (minerals) and also many species use both to make homes.
The idea is that in our biochemistry systems we are like an oven that builds itself. We break down (burn) the things we eat into small bits (Wood becomes ash). This process already provides some energy, since the way the building blocks our food is made of are not always arranged in the most optimal way. The difference in "optimal alignment and seperation" of those blocks gives us energy to run our cells. We then use the parts we broke down, arrange them differently and build the parts of cells or molecules we need (making bricks from ash).
To get back to the question, the most difficult thing is not breaking down these things, it is actually using them in a meaningful way and having the process be efficient. It would be like trying to burn wet wood or trying to burn these very hard to burn things. If something burns it basically rearranges the parts it is made of in a more optimal way, the flame you use to start that process is just the first domino brick.
So the answer is a combination of reasons:
First of all the difference for the examples is one is hard to break down others are easy with regard to the energy you have to put into it to break it down (chemically speaking)
You also are left with things our body cannot really use to fix itself. We have the buildingblocks of these examples in our body but they are not in the right ratio. For example you have probably heard that we consist of hydrogen carbon and oxygen. Those are all vital parts in fats carbs and proteins. They are all carbon atoms chained together with hydrogen and oxygen is often used to bond combinations of them together. So we literally are what we eat.
Hope this helped :)
I like the vision that we are the biological ovens that burns itself.
Evolutionarily, an animal of any measurable size relying on a difficult to process food source is a losing strategy. It's not unheard of though; bacteria do eat clay, rock, etc. They're also more abundant than basically all other lifeforms except perhaps Archaea, so theoretically it's possible that "most life" does in fact subsist on non-nutritive sources. For larger organisms the problem is that cells need certain materials to function--fat, protein, carbs--which are in higher abundance within their accessible environments. But they still need and get trace minerals because they already occur within their food sources (thanks to all that bacteria/archaea).
This is sort of a complicated question because it can mean two different things.
Fats and carbs are ways that plants and animals have found to store energy. You can burn (literally) fat and sugar. You can't burn clay or feldspar. In other words, rock isn't a source of energy.
The other question is why do plants store energy as hydrocarbons instead of something else? That's a lot more complicated but, as molecules go, hydrogen and carbon are both super common, carbon with a valence of 4, is pretty versatile and converting water (hydrogen-oxygen) to hydrocarbons (hydrogen-carbon) produces bonds that are higher energy but stable enough for storage yet unstable enough to reverse easily when the energy is needed. Could something else have won out? Perhaps but most other combinations are too rare, too stable or too unstable to be useful.
DNA, RNA, and the base of proteins are made of hydrogen, oxygen, nitrogen, carbon and phosphorus. Wherever organisms are living they need a supply of those elements, so living in diamond for example won't work because it's all carbon and nothing else.
But other types of minerals can work, many microorganisms live in and can digest rocks or live around deep sea hydrothermal vents etc.
Most substances that have been sitting around for billiins of years exist in stable, low energy states. We can pretty much only get energy from the sun. But plants used sunlight to separate oxygen from carbon and hydrogen in order to build and power themselves. This created a high energy system of reduced hydrocarbons and oxidized oxygen. The rest of us can steal this energy by reuniting the plant material with oxygen.
Because life evolved ATP.
ATP is a good storage of energy because it releases a lot of energy for very little effort. The phosphate groups of this molecule basically detaches with little effort and releases a lot of energy that our cells can use.
ATP is what allowed life to become multicellular and therefore explode in complexity. Others have given examples about microorganisms that do digest metals but since they arent energy efficient like ATP, they are stuck in their evolutionary niches.
We eat sugars carbs and proteins because they make ATP. Sugars, carbs, with water and oxygen basically combine to create ATP.
ATP was such an efficient molecule that it allowed everyone who uses it(basically every animal and plant) in the world to explode in numbers.
Because even though most molecules suck for life. We are carbonbased because carbon can create long modular molecules that are not too instable that everything explodes but also not too stable so that no chemical reaction can happen.
https://youtu.be/kAFC4RY1cKQ?si=Zd0R_oGLnmhVPTu0 I think this video gives a very good overview of the multiple reasons why life on earth is based on the molecules we use.
Have you looked up extremophiles yet? Some live in a Goldilocks zone around deep sea volcanic vents and love the sulphur.
Lots of different molecules have different amounts of energy. 1 gram of uranium contains about 20 billion calories of energy. 1 gram of Gasoline contains 10 calories. 1 gram of protein or carbs contains 4 calories. So why do we only get calories from eating proteins, fats, and carbs instead of other potential energy sources?
The simple answer is: plants and animals all evolved from a similar ancestor. Plants evolved to take the energy from the sun and convert it to mass/energy to sustain itself. Animals evolved to be able to consume plants and convert the plant cells to mass/energy to sustain itself. Millions of years of evolution continued until humans finally arrived. Our digestive system developed to be able to get energy from certain plants and animals. They contain many of the same building blocks as our body has and our digestive system is able to convert those building blocks into raw materials our body can use. Lots of plants and animals are not edible as our body never developed the ability to digest them.
Life as we know it is pretty much animal, plant, fungi, or bacteria. These are indeed all carbon based.
Of all the life we know, practically speaking theres really only two ways to get energy to fuel life. One is consuming other organisms and the other is photosynthesis. Neither of those is able to convert minerals like rock or iron into fuel.
There are of course some very, very rate and only recently discovered forms of bacteria which seem to deviate from this by using heat from deep sea thermal vents or extracting tiny amounts of energy from sulfur to survive.
There are.
Waaaaay back in my college days, I worked with a bacteria called Thiobacillus ferrooxidans that eats iron. Basically, it got energy from the reaction that causes rust.
However, there's a couple problems:
Which gets to the reason why there aren't more things eating raw materials: breaking them down yields very little energy or the material is already as broken down as it can be.
Life concentrates usable energy and concentrated usable energy is very "naturally" uncommon. Pretty much any energy rich substance on the planet (anything that can combust) is a product of life.
Not a direct answer, you’ve already got some wonderful ones. But I’ve found these are truths you can apply to almost any biology and many chemistry questions.
You need things that can change stuff, you need things that can move stuff, and you need stuff to make the structure.
Oxygen is great for changing stuff, it’s very reactive will stick to things or break them up to become new molecules. Almost everything that touch oxygen gets changed by it.
Water is great for moving stuff. It’s a great solvent, which helps things move around like to different parts of or transfer in to/out of a body and it can hold a tonne of stuff in it. Almost everything will dissolve into it.
Carbon makes a great structure. It’s strong, it’s stable, and it’s abundant. And everything wants to stick to it.
It's likely due to how the earliest life used ATP/ADP as their primary energy source and that molecule requires: A simple sugar, a phosphate, and a nitrogen base. Fats/carbs/proteins provide all of those, well, or the sun... but the kreb cycle is still generating ATP.
There is an alternative in the form of GTP, but it's still basically a sugar, a nitrogen base and some phosphates.
The reason ATP is used it likely because it shares the components with RNA for simple duplication of RNA and therefor reproduction.
...
As for the alternatives in your question; diamond COULD be a source of the carbon, but it would be very inefficient compared to graphite. Other rocks are mostly silicates; If a creature's equivalent to rna needed copper they'd eat malachite, if they needed aluminum they'd eat feldspar or bauxite... MAYBE (speculative). Many rocks do contain oxygen in their composition.
So, the missing link is hydrogen... which can enter rocks via processes like Serpentinization, but ya.
Summary: Cuz ATP fueled RNA generation, in my opinion
Most living things can’t eat stuff like rocks, metal, or diamonds because there’s just no useful energy in them, and they’re way too hard or unreactive to break down. Fats, carbs, and proteins are like nature’s fuel, they’re packed with energy and easy to use. A few weird microbes can get energy from certain minerals, but that’s pretty rare and nothing like how we eat food.
For the record, we ingest lots of minerals for our ongoing energy/health. These things are on the periodic table….calcium, magnesium, potassium, lithium. Etc.
our bodies need energy from breakable stuff rocks and metals don’t have the right kind of fuel we can use
Food accomplishes two things:
In order for the body to use something for one of these purposes there needs to be a chemical reaction:
Diamonds for example are ALL carbon so you'd think a carbon-based lifeform would love it. But unfortunately the structure that makes carbon atoms into diamonds is incredibly hard to break up so it "costs" more energy to break it up than you would get out of it.
Rocks often contain elements the body does infact need (like magnesium, iron, potasion, calcium) but again they exist in a form where the body cannot split what it needs from what it doesn't. There are bio-chemical reactions that would allow this but the human body doesn't need enough of these things to make it worth the trouble of setting up this reaction, when plants and bacteria further down the food chain have already done this "for us" and we can just eat them instead.
It's like trying to grow your own pineapples in the high alps. With modern technology like grow lights, artificial irrigation and finely regulated heating you could absolutely do this. It's just so much easier to have them grown outside in the tropics and ship them over at a scale where they cost a few bucks a piece.
You eat things for fuel. This means stuff that will "burn" easily.rocks and Metall don't burn easily. They can, but most of the time there are things that will make for better fuel.
Diamonds will burn. They are just shiny lumps of coal, but you can't eat pure coal either.
Mostly we evolve to use what is easily available, brings the most energy and what we can easily access by tweaking stuff we already have.
Stuff that is too rare, hard to extract energy from, doesn't contain much energy or would be too different from things we already have tools for is something we don't evolve to make use of.
We do need elements such as copper, iron, zinc, etc to function properly. The problem is that they have zero available energy. We get our energy from hydrocarbon bonds. This is why salt, NaCl, has 0 calories.
Not a scientist here.
Here is my answer: Either because mechanisms for turning material X, into energy exist but unreachable via natural evolution (because organ for, say, rapid kerosene digestion is very complex / specialized and will be a burden for all generations until evolution 'completes' it) or, because there are much better alternatives available. Sure, using the best possible source of energy can backfire (when it become scarce, suddenly), but most of the time it will offer critical advantage instead. In other words, if ability to eat something is very useful once in 100.000.000 of years, then, it will be simply selected out (unless it serves other, important role too!).
PS: I am aware that kerosene doesn't occur in wild nature.
PPS: That being said with genetic engineering, you can make an animal (including us) to be even more omnivorous that we currently are.
We do not get energy from matter, but from how the matter is aranged. To arange carbon mollekules in a way that is fats, Protein or sugar energy is used, mostly solar Energy (Photosyntheses) but sometimes other energy, line Geothermic, then later, when we eat it, we break the fats, sugars and Proteins apart again into carbon and water.
When you eat food, your body doesn’t make the food disappear. It just takes it apart into tiny pieces and uses those pieces to give you energy and help you grow.
After your body uses what it needs, the leftover pieces come out as poop, pee, or breath (like when you blow out air). That stuff doesn’t vanish — it goes back into nature.
Plants can take the stuff from your breath (called carbon dioxide) and use it to grow. Then animals eat plants, and people eat plants or animals. And it starts all over again.
So the food and stuff you eat turns into energy for you, but the little building blocks, called matter, don’t go away. They just go around in a big circle and get used again and again.
This ignored ofcourse the few trace Elements like metal used in our blod, or other thibgs like Vitamins,or the few pieces that don't leav the body but get used to maintain it, but it's good enough i think.
Could Other Elements Work? Scientists have asked this too — especially when thinking about alien life. Some maybe-candidates include:
Silicon Right below carbon on the periodic table.
Can also form 4 bonds, like carbon.
But it's less flexible: it forms fewer complex shapes.
Silicon compounds (like silicones) are less stable in water, and they don’t work well at Earth-like temperatures.
Some people imagine silicon-based life might exist on other planets — like ones that are hotter or have different atmospheres (like ammonia instead of water).
These Lifeforms too would not destroy matter of eaten but Like us humans just take them apart extrakting thos connection energy and releasing the compounds back in the cycle, for other Lifeforms to use.
Because stuff like rock and clay are already at their lowest energy state. They are what remains after their parent materials (bigger rocks and unoxidized molecules)released their energy.
Diamond is different, it has lots of energy available but the bonds holding it together are incredibly strong.
Fats and carbs and proteins are like stacks of energy that life processes have built up. They make great energy sources because it's easy to knock them down to release that energy.
It's that same reason why nothing can survive by consuming water. It takes more energy to break the molecule than you can get out of it.
I think there are two main parts to this:
Structures that exist specifically to be as useful as possible for living things to store and access energy are going to make for a better food source than pretty much anything else by definition.
And if any of those other things were particularly good sources of energy for living things, they would have already been eaten and turned into fats/carbs/etc.
Simple. Life sustains life. We don't get life from non life.
Energy is released by breaking chemical bonds in materials. These bonds are much easier to break in carbon chains than in the minerals you are proposing. I'd tell you to research cellular respiration but that's basically college level biology, and if you're asking this you are unlikely to understand it well... but that's a place to start to understand that process if you want to put the time in.
[removed]
Please read this entire message
Your comment has been removed for the following reason(s):
If you would like this removal reviewed, please read the detailed rules first. If you believe it was removed erroneously, explain why using this form and we will review your submission.
Because fats, carbs and protein are energy while the other things you mentioned are basically elements.
most organisms rely on fats, carbs, and proteins because they're easy to break down and rich in energy.
materials like rock or diamond are too stable chemically, so there's no efficient way for life to extract energy from them.
And yet, life uh finds a way...
https://en.wikipedia.org/wiki/Lithotroph
Lithotrophs still rely on fundamentally the same molecular mechanisms to extract energy, it's just using different substrates. In fact, our mitochondria actually use hydrogen sulfide occasionally as an energy source, so lithotrophs are still using very ancient energy systems that have common chemical processes. OPs original comment on what types of materials can be harnessed for energy could not use the Calvin cycle because these materials are not soluble and have very high thermodynamic energy barrier to overcome.
This broken down to be so easily understandable makes me think you work in a very technical field where you have to explain big things in easy ways
Haha, bingo. I work in the food industry as a technical consultant who often has to explain to executives why it might not be a good idea to put stuff like raw milk (among other things) in the food system.
now if you could only explain it to food or "wellness" bloggers
It’s been a losing battle
Thanks for that example. I grew up on a dairy farm and fondly remember drinking raw milk daily.
Even I know thats a real bad idea, so much so I wont even try a local farm's raw milk.
I mean, doesn't raw milk go through the same testing and safety procedures typically? My understanding was that if it failed testing, it likely meant the cow was not healthy, so raw milk that passes means the cow was healthy, whereas you can pasteurize milk from unhealthy cows and still sell it. A friend told me this years ago when we were regularly drinking raw milk. I never went deep into researching it tho!
The problem is maintaining those standards with consistency.
Think of every time there has been a food recall in your lifetime, like Lettuce and E.Coli.
Now, consider the fact that the lettuce underwent a process that is supposed to make it safe to eat, as Raw Milk would undergo.
Then, factor in how much more dangerous the bacteria in Raw Milk can be, and how prevalent Milk is in the average American Household.
Furthermore, there aren't any proven benefits to drinking Raw milk over Pasteurized milk, so it's a completely unnecessary risk.
does that mean that our macronutrients are chemically unstable?
I think you have the right idea, but the word 'stable' is extremely relative. It can mean anything from diamond to compounds that don't spontaneously combust in air, depending on context.
How I'd put it is that our body takes stuff with higher chemical energy (more unstable compounds) and transforms it into stuff with lower chemical energy (more stable compounds). Assuming no loss, that difference in energy is what we get out of the reaction.
I see. So macronutrients are just less stable. And when we eat food, what comes out is more stable than what comes in.
It would help to think where the energy comes from.
For us, as human, all the energy we run on is derived brom breaking some 'unstable' chemical bonds that only exist because a plant somewhere decided they wanted to make those chemical bonds using energy from the sun.
The chemical bonds themselves are really not that unstable, but neither are they very stable. They are metastable. Which just means there's energy inside, but you gotta spend a bit of energy to get a lot more energy out.
A more accurate word would be "high chemical potential energy". Like a ball at the top of a large hill would have high gravitational potential energy.
If the slightest breeze can set the ball rolling down the hill, then it is also unstable. But if the ball is glued to the ground, then it is stable.
Macronutrients are like the ball glued to the ground. You have to have the tools to unscrew it (enzymes) to get the energy. Or you could just smack it really hard with a hammer and break the screw (set it on fire).
and you can't digest those materials