Background Info

One of my stories features the classic isekai trope of a person being reincarnated into a baby's body while still retaining their full cognitive abilities. The world they are reincarnated into has magic and a level of technological development somewhat akin to that of the 1600s. Otherwise, the world is largely identical to our own.

Soon after birth, this person finds themselves abandoned in the woods by their parents for some reason. Thankfully, they were a Bear Grylls-like survivalist in their past life and know how to find and identify various food sources like berries, nuts, seeds, roots, fruit, and honey, while also knowing how to hunt small game like rabbits, squirrels, fish, etc. They will also be able to find clean water at a nearby river.

Now, this person is of course a baby, and normally would be dead within a day. Thankfully however, being the protagonist of the story, they are abnormally talented in magic, which they can use to float their body around, dig, forage, hunt, remove skin and organs from game, protect themselves from the elements and animals, start fires, freeze food, form containers (e.g pots for boiling), produce light, and basically anything else they would need to survive.

Story-wise, they could likely use magic to find their way back to a village and then be raised by people, but that is not what I am aiming for, and so at the absolute most their interactions with nearby settlements will be stealing things like bread and cows milk.

The Diet

The diet in question will be one of nuts, seeds, berries, fruit, roots & tubers, honey, eggs, and meat. They may occasionally steal cows milk and bread from nearby villages. They can cook and freeze whatever necessary in order to make food more edible, destroy parasites and bacteria, and make it last longer. They can also use magic to turn the food into mush before eating it, as they won't have teeth to chew food.

They will drink clean water from a river. They may boil it before drinking if necessary.

The Question

With all that information in mind, would this person be able to grow and survive off this diet? They will not have any access to human milk, only being fed by their mother maybe once or twice before being abandoned.

Please note that answers should focus primarily on diet and nutrition, any answer that focuses solely on the practicality of a baby surviving in the wild will be regarded as low-quality.

  • $\begingroup$ That plot is kind of already an anime: Jitsu wa ore saikyou deshita $\endgroup$ Jul 10 at 0:05
  • $\begingroup$ @TitaniumTurtle it follows the story beat of 'reincarnated person abandoned as a baby' but he's outside for a total of about 30 minutes. $\endgroup$
    – M S
    Jul 10 at 7:02
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    $\begingroup$ If they can produce light and freeze stuff, then they can probably manufacture their own baby milk... $\endgroup$ Jul 10 at 9:16
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    $\begingroup$ Honey is not recommended for infants under 1, since honey can contain botulism spores. Honey is the best available sweetener in the paleo diet, so your character will have to gamble with their health if they want to make baklava. $\endgroup$
    – skeep
    Jul 10 at 10:13
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    $\begingroup$ If you have arrived at this question interested in the possibility of a YES answer please be aware that this question has been asked for the purpose of a work of fiction. Any suggestion here that a newborn or young child could survive on a paleo diet without consultation with a medical professional risks the health of the child. Please do not accept affirmative answers provided here as authoritative or a sufficient replacement for medical expertise. (Every once in a while we receive a question that carries too many consequences if someone believes the answer.) $\endgroup$
    – JBH
    Jul 10 at 19:23

8 Answers 8


Only if it is mostly milk.

Assuming they are eating mostly dilute animal milk (goats' milk is best), and mixing in some of the sterilized puree to supplement vitamins, yes they can survive on it. It's not the best but is possible.

Humans infants simply cannot digest most other sources: milk comes with digestive enzymes built in; non-animal based formula has to add in those enzymes from industrial sources.

Humans need a lot more iron and vitamin C than cows' - or really any animal's - milk provides. This is where the fruit and nuts can help.

Animal milk usually needs to be diluted a little as it is rather dense compared to human milk and can damage developing kidneys. Goats' milk is better than cows' milk if available; it is a LOT easier for humans to digest.

Cows' milk is the main ingredient in modern artificial formula due to price. Most of the processing is about replacing fats and adding digestive enzymes, vitamins, and minerals.

They need to sterilize water and additives but at least a few feedings of milk must not be sterilized. Infants need some gut bacteria from at least a few non-sterile feedings.

Milk from cows, goats, sheep, donkeys, camels, pigs, or horses have all been used successfully in the past so you have options. Feral goats, pigs, and horses can be fairly common (they are good at escaping) so it's not unbelievable to find some in the woods especially if it is close enough to a settlement for a new mother to travel there by herself to abandon a baby.

History of using animals' milk

How formula is made

It is worth noting that even a single feeding of human milk will make the infant a lot better off, as it supplies gut bacteria and immune system priming. In a bit of morbid history, a dead mother can still supply a single feeding.

  • 1
    $\begingroup$ Maybe the baby was abandoned a few days after birth, not minutes, and already had that first milk. $\endgroup$
    – DonQuiKong
    Jul 10 at 17:45
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    $\begingroup$ @DonQuiKong "They will not have any access to human milk, only being fed by their mother maybe once or twice before being abandoned." $\endgroup$
    – Kirt
    Jul 10 at 18:12
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    $\begingroup$ A really interesting aspect about this answer is that, while it's entirely possible, I wouldn't expect a survivalist to know this. They would know to boil water, would figure out how to find, capture and milk a goat, and would know that fruits and nuts add iron and vitamin C. They could guess a baby can't digest roots and stuff. But I wouldn't expect them to know that cow milk doesn't have enough iron and vitamin C for a human, or that a short travel to a village to get one single feeding of human milk would be so beneficial to them. How the author uses that will be interesting. $\endgroup$
    – Blueriver
    Jul 10 at 23:47
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    $\begingroup$ The sterilization requirements tend to be overstated. It's not long before a newborn starts touching everything in reach, and then placing its hands (and any object it can grasp) straight into its mouth. Unless you live in an autoclave, none of these things will be sterile. And of course newborns managed for tens of thousands of years before autoclaves and modern food-handling/sanitation practices were a thing. Contaminated/rotten/poorly handled/stored food is a concern, but in general if your ingredients are fresh and clean that's safe enough. $\endgroup$
    – aroth
    Jul 11 at 4:06
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    $\begingroup$ @aroth sterilizing the water is the most important, stream water is dangerous for adults, an infant has basically no defense against dysentery or cholera. heck, one bout of diarrhea is a death sentence for this infant. Also keep in mind "managed" is a relative term here infant mortality was almost 1:4 in before modern medicine. $\endgroup$
    – John
    Jul 11 at 12:56

A new born baby, even though might be capable of hunting, fishing and cooking, has still severe limitations in what they can consume for sustenance.

With no teeth for chewing and a rather immature digestive system, they are going to have a though time in finding a food they can consume.

When in the past a newborn could not get breastfed from their mother, their hope of survival was in finding another woman who could breastfeed them. Even though the family of the newborn could provide other food, they were of practical no use.

Anecdotally, my granma told me that in her times, before WWI, a rather extreme attempt would have been to feed the infant with yellow split peas puree.

Also, don't forget that a new born gets, through their mother's milk, the antibodies that their body is not yet capable of producing. No matter how sterile is the food, surviving in the open would require an efficient immune system.

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    $\begingroup$ Find a wet nurse, not necessarily human. A she-wolf did for Romulus and Remus, and a goat did for Zeus. $\endgroup$
    – AlexP
    Jul 9 at 19:40
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    $\begingroup$ @AlexP With the caveat that we're talking about mythological beings who did not exist. Milk from most animal farms is not going to be really suitable for humans. In animal breed on captivity there have been several examples of an animal breastfeeding pups of another species, but that's hard to see in the wild. Maybe the baby can use mind-controlling magic to acquire a suitable non-human wet-nurse, but once we're bringing magic to the table a human one would work best. $\endgroup$
    – Rekesoft
    Jul 10 at 10:31
  • $\begingroup$ @Rekesoft: I really do not have any specific formal knowledge, but wasn't goat's milk used for thousands of years as a substitute for mother's milk in cases of emergency? Yes, it is not exactly what's best, but doesn't (yes, anecdotal) historical experience show that it works more often than not? At least the folk-knowledge it is sufficiently well-known to work in fiction with no friction. $\endgroup$
    – AlexP
    Jul 10 at 12:48
  • $\begingroup$ I know that cow's milk is not a good substitute. Maybe goat's milk was used because it was better... $\endgroup$
    – Rekesoft
    Jul 10 at 13:37
  • $\begingroup$ @AlexP Donkey's milk was preferred to goat's milk in some places at least $\endgroup$
    – Chris H
    Jul 10 at 15:41

Only if they are older than 6 months

That's the earliest that Babies can have 'real' food. Any earlier than that and IIRC their stomachs can't process it. Regardless of how much Magic the Baby has.


On top of what everybody said... as a parent of two kids who has read a lot about diet and discussed it with pediatricians and dietitian doctors, I have one more piece of data to add here.

Unless you live in an environment that is too hot and dry, you should never give water to a baby that is six months or younger. And if you have to give them some water, you need to follow a pediatrician's reccomendations for water to milk ratio.

That is because babies that young are really bad at regulating salinity in their bodies. Maternal milk has just the right amount of salts (and sugars, because that also regulates osmosis somewhat) to keep a baby alive. Give even just a tiny bit of water to a newborn and they can die in minutes because their blood gets dilluted.

If your wizard baby is going to be eating anything other than milk, they'd better be stealing formula from somewhere or they'll have to be a biology and chemistry wizz as well to figure out the salinity and sugar ratios.

By the way, I fed both my kids formula. The protein in Enfamil (my preferred brand) is about 60% whey and 40% casein, I believe. Those are found in milk. Other proteins aren't as good. Your baby wizard will therefore need milk anyway because plant-based protein won't do (ask any responsible vegan parents), and meat, fowl, egg and fish proteins aren't digestible for babies. I believe insect based protein wouldn't be digestible either.

Push comes to shove, the little mage may have to use magic to either charm or bloodbend a she-goat into breastfeeding them. I do hope they do the former or you will have a severely, mentally traumatized goat.

  • $\begingroup$ +1 - interesting answer, but I really appreciated your comment about the mentally traumatized goat! $\endgroup$
    – Basya
    Jul 12 at 10:13
  • $\begingroup$ Since I didn't really believe the bit about how unsafe can water drinking be to infants, here's a link that says the safe limit is about 3 oz = 80 ml: stlouischildrens.org/health-resources/pulse/… $\endgroup$
    – svavil
    Jul 12 at 21:16
  • $\begingroup$ @svavil the article doesn't mention ages. Most professionals worldwide say water can be safe after 6 months. Before that the recommendation to re-hydrate a baby is to prefer extra feeding whenever possible. Here is an article that us more specific about that: pregnancybirthbaby.org.au/amp/article/… $\endgroup$ Jul 13 at 2:16

It has been demonstrated* (see below) that babies as young as 9 months can manage their own diets if presented with a sufficient range of natural whole foods without any adult direction.

Prior 9 months (or may be 6 months or less) there would be increasing issues with the babies abilities. The very youngest of babies would not have the mental capacity to feed themselves using their hands and would be intent on suckling.

However given the somewhat magical situation in which a baby was capable of levitation and all manner of other activities it is not clear how things would develop and is dependant on what assumptions you make.

If it is reasonable to suppose that such a young infant has all these abilities then it is only a short step to assume that the baby actually knows what it needs for nutrition (as older babies do) and that would be milk so the baby would probably instinctively gravitate to a teat to drink milk from any available animal.

If you want to exclude that possibility and ask is it possible for the baby with magical powers to survive without milk, I would say the answer should be no as the babies digestive and immune systems would not be sufficiently developed for solid (even mush) food from birth.

That said if magic is involved then anything is possible. Perhaps the baby can magically modify other foods into milk. Animals have the ability to convert whole foods into milk so why shouldn't a magical baby?

An insight may be found in an interesting experiment that was conducted in the 1920's. Although it would never be considered ethical today it demonstrated that after weaning babies were entirely capable of selecting their own foods and managing their own dietary intake for healthy growth.

They were presented with a wide range of natural whole food and given no guidance as to what to eat, but were perfectly capable of feeding themselves with a well balanced diet. As would be expected as other mammals have this ability.



Depends on age

Strongly depends on the age of the baby. Right after birth? Unprobable, since the digestive system isnt yet fully developed and couldn't handle much else than breastmilk. 6 Months+ would be more realistic. At that age babies can digest most normal food.

But he still would need knowledge of what nutritons each food he can forage contains and what nutritions and in which amounts are needed for a baby his age. This is important since the neccessary nutritions of a baby differ extremly from those of an adult and a baby has a small stomach so it can eat only a small amount that needs to provide those nutritions. For other nutritions a baby can easily "overdose" and permanently damage its organs, like for example eating to much proteins (e.g. lots of meat) would lead to kidney failure of your hero, ending the story prematurely.

So your hero would need:

  • Survival skills (you already mentioned that)
  • At least decent knowledge of nutrition contents of "foraged food"
  • Good knowledge on feeding/providing for babies

You seriously need to get some milk into that baby. Like there is no way around it. Maybe the protagonist can go around the woods using magic to detect small animals that are nursing their offsprings, then killing them and draining them of milk. Make him a completely ruthless murderer of animal mothers. That could make him contemplate his actions later on. Like with every kill he makes a promise to the forest to pay back his blood debt with his own blood or something like that.

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    $\begingroup$ Why go straight to killing, though? A live mother produces a whole lot more milk than a dead one. $\endgroup$
    – Martha
    Jul 12 at 18:39
  • $\begingroup$ Completely agree. OP can use this however they see fit. However, making it a moral decision to survive at the expense of the lives of innocent animals should build some complexity that could be used later on. $\endgroup$
    – Jacob
    Jul 13 at 7:33

If you're not afraid of needles and know some advanced alchemy ;-) you could perhaps use intravenous feeding:

"Total Parenteral Nutrition fully bypasses the GI tract and normal methods of nutrient absorption" https://en.wikipedia.org/wiki/Parenteral_nutrition


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