Quote from wavygravygadzooks on April 7, 2021, 3:51 pm

Mary Ruddick and Brian Sanders have their own podcast on Youtube (Peak Performance) on visiting the same Hadza group as Paul did.  I think they might answer some of your questions that Paul didn't get around to, I really liked their podcasts on their Africa trip.

I have been following Paul for about a year now.  I think he's done an admirable job of synthesizing the published information out there on the benefits of an animal-based diet, and the reasons to avoid plant foods and which ones are most likely to be problematic.  However, I think he's taken the organ eating a bit too far, and he introduced a major conflict of interest to his discussion when he started selling supplements.  Organs do typically have higher amounts of nutrients than muscle meat, but unless all you're eating is organ meat, it seems to me that you're not really going to get meaningfully more of the common micronutrients (e.g. B vitamins) by eating organs in proportion to the muscle meat you would get by killing and eating an entire animal.  You might be getting nutrients we haven't identified yet...you could make an argument for that.  What you are definitely going to get a lot more of is Vitamin A though, and we know this is a problem for some people.

I think Paul has actually fallen victim to the same logic he uses against mainstream nutritional advice, which is that he is leaning on reductionist nutritional studies that suggest we need X amount of such and such nutrients to be healthy.  In the end, experience trumps any reductionist science.  It doesn't matter how many studies you have that suggest X nutrient is needed in Y amount to prevent cancer if there are groups of people living healthy, cancer-free lives on lower amounts of that X nutrient than what is recommended in the literature.  I think all the people experimenting with a "civilized" version of carnivore, which is essentially all muscle meat and fat, will go a long ways toward illuminating the basic elements of what humans need from food.

Personally, I think modern hunter-gatherers eat as much organ meat as they do primarily because it maximizes their nutrient intake for a given amount of energy expended to get an animal.  They are typically very healthy, live an evolutionarily consistent lifestyle outdoors, and have the means of expelling any extra nutrients/toxins like Vitamin A that their body needs to get rid of.  Like any animal, they are opportunistic, and given that they have limited energy to expend, they will typically consume as much of an animal as they can without expending more energy/nutrients than they're gaining (i.e. if they can easily break the bones to eat the marrow they will, but if it takes too much effort to break them, then they won't because it would represent a net loss).

Quote from tim on April 8, 2021, 1:11 pm

I think that taste preferences for liver give us a big clue. If the Hadza found liver as revolting as I do they would never eat it. I see a big genetic component here. I think that genetically many people that had many low vit A consuming ancestors are more likely equipped to store it and conserve it. However, just as there is variation in lactose tolerance among members of the same gene pool so is there variation in vit A tolerance. This is backed up by evidence showing siblings can have very different tolerance levels for vit A.

Quote from wavygravygadzooks on April 8, 2021, 1:41 pm

@tim-2 Taste is largely a product of conditioning though, and it can change on a very short time scale.  I could eat mounds of sugar and fruit until I cut them out of my diet, and now more than a couple bites of fruit tastes disgustingly sweet, especially domesticated fruit.  Hunter-gatherers that eat fermented meat think it's the best thing in the world, but the smell/taste would turn almost every other person away in disgust.  However, it's quite possible to adjust to things that initially repel you, and to be better for it in the end (in the case of many an explorer who adopted native forms of food).  It's also possible to become used to eating things like sugar and destroy yourself in the process.  In order for taste to guide us in the right direction in modern times, it has to have a cultural foundation to work from.

I think, if anything, you've got the genetics argument backwards.  Considering that it was historically impossible to avoid eating preformed Vitamin A and/or carotenoids, and that there would be a benefit to being able to tolerate MORE Vitamin A from organ meats in order to make use of the other nutrients in those organs, I would argue that some people (such as the Inuit) would have adaptations that either prevent absorption of Vitamin A or speed its excretion once absorbed.

Do those sibling studies control for diet or lifestyle?  Those factors are probably going to play a larger role than genetics for most people.

Quote from Sarabeth on April 15, 2021, 6:28 pm

I appreciate your perspectives! And haha, I certainly can resemble the person who develops different "tastes" depending on what I happen to Believe for dietary dogma er Dietary Decision Making this year. 🙂 Lately I am, like Tim, very grateful not to have to force myself to eat liver and pretend to like it to set a good example for my kids. I also don't miss vegetables hardly at all, except I did love squash and mangos and watermelon... Sometimes I think my tastes might be broken, and wonder how/whether it will be possible to address certain niggling issues: spooning/flattening/brittle nails, certain leaky gut intolerances (wheat, dairy, etc.), one child's bedwetting...it feels almost impossible to follow our instincts because they are so easily co-opted by short-term taste buds.

Quote from tim on May 1, 2021, 10:24 am

@wavygravygadzooks

"Taste is largely a product of conditioning though, and it can change on a very short time scale."

It's not though... it's strongly instinctual. My pet dog used to love lapping up fresh cow dung, anyone reading that might feel their stomachs turn a bit, an instinctual reaction to protect us from harm. My pet dog wouldn't touch fruit though, she had very different instincts around taste.

Three men were shipwrecked on a sub Antarctic island and forced to live carnivorously eating mostly seal meat. When they were rescued they devoured the freshly baked bread they were given before anything else, they were on the island for years and they had adapted to the diet due to necessity but starch is the most efficient source of glucose by a long shot and they intensely craved it after all that time. On the other hand Inuit have made significant genetic adaptions to their diet and can perform gluconeogenesis more efficiently than other ethnicities.

An Indonesian tribesman whose native starches were root vegetables cried after eating white rice for the first time and when questioned stated that it was because he'd never have it again. He wasn't conditioned to enjoy his native foods, it just was all he had.

"However, it's quite possible to adjust to things that initially repel you, and to be better for it in the end"

It's definitely possible for us to adjust to foods that go against our instincts to a degree but it's normally a learned behavior in order to survive rather than thrive due to the said food providing some unique nutritional or medical benefit however when it comes to macronutrient balance the body always wants plenty of protein, fat AND carbs.

I've tried to enjoy liver many times but never could which makes sense because it doesn't provide me with any unique nutritional benefit yet it contains toxic levels of vitamin A.

"I think, if anything, you've got the genetics argument backwards.  Considering that it was historically impossible to avoid eating preformed Vitamin A and/or carotenoids, and that there would be a benefit to being able to tolerate MORE Vitamin A from organ meats in order to make use of the other nutrients in those organs"

You seem unclear about what I wrote. Many neolithic populations certainly could have developed adaptations to both conserve vitamin A and to minimize excretion, paleolithic peoples may have been more equipped to process vitamin A. However, it wasn't impossible to consume a paleolithic low vA diet at all, in fact there is documented evidence that I've previously posted showing that even hunter gatherers suffered from xeropthalmia and knew of liver as a cure (implying that for many it wasn't a part of their normal diet). Many of them didn't consume many carotenoids and they didn't have dairy so if they didn't eat liver the diet was not high in vitamin A.

"I would argue that some people (such as the Inuit) would have adaptations that either prevent absorption of Vitamin A or speed its excretion once absorbed."

If you reread what I wrote you'll see that what I wrote doesn't disagree with that.

 

Quote from wavygravygadzooks on May 1, 2021, 1:50 pm

Taste is driven by a combination of instinct overlain by culture and personal history.  Our basic instincts lead us to protein, fat, and carbohydrates and steer us away from toxins, but instincts aren't foolproof.  Do you think kids that gorge on candy are doing themselves good?  They're responding to an instinct for carbohydrate consumption, but they require cultural input and learned experience to keep them from routinely overconsuming empty calories.  You may have an aversion to liver because of the high copper content if your body is already full of copper, which may be your body's instincts serving you well.  Or you may have an aversion to liver simply because you've not eaten it regularly and your body at its age has developed a wariness of new foods.

I'm in my mid 30's and I didn't eat any fresh liver until the past couple years.  When I did start eating it, I thought it was delicious, although I could detect some mild bitterness in it (I think it's probably the copper I was tasting).  I was already badly Vitamin A toxic, and I definitely was not deficient in copper, yet my body's instincts were signaling to me that this was an appropriate thing to eat.  How would you make sense of this? 

We don't have taste receptors for Vitamin A, and there's apparently no instinct to avoid either carotenoids or preformed Vitamin A even when we're toxic.

"It's not though... it's strongly instinctual. My pet dog used to love lapping up fresh cow dung, anyone reading that might feel their stomachs turn a bit, an instinctual reaction to protect us from harm. My pet dog wouldn't touch fruit though, she had very different instincts around taste."

All this anecdote suggests is that your dog might have been nutrient deprived from an unnatural diet (dogs that consume feces of any kind are potentially nutrient deprived).  I don't know what you were feeding it, but if it was commercial dog feed, you could argue that your dog became habituated to eating dog "food" even though it was not an instinctual diet.  As for fruit, canines are facultative carnivores, they largely depend on animal meat and fat for survival.  Some of them will eat wild fruit, but the fact that a domesticated canine didn't like mutant fruit cultivated by humans doesn't say much about the instincts or behavior of animals.

"Three men were shipwrecked on a sub Antarctic island and forced to live carnivorously eating mostly seal meat. When they were rescued they devoured the freshly baked bread they were given before anything else, they were on the island for years and they had adapted to the diet due to necessity but starch is the most efficient source of glucose by a long shot and they intensely craved it after all that time. On the other hand Inuit have made significant genetic adaptions to their diet and can perform gluconeogenesis more efficiently than other ethnicities."

Are you referring to the Shackleton expedition?  My wife just happens to be reading about that right now...they were burning the fat to cook the meat!  They were probably approaching rabbit starvation by subsisting mostly on lean meat, so of course they're going to be craving glucose when they're rescued.

You seem to be ignoring the fact that the instinctive response of these men was to NOT eat seal.  If anything, they were repulsed by it, even though it was a nourishing food.  They had to override their instinctual revulsion of something that saved them, and the reason it saved them is because it had considerable nutritive quality.

Most of the Inuit who have been provided access to high energy processed foods have experienced deteriorating health, yet their instincts do not stop them from continuing to eat that food.  Their instincts tell them easy calories = good, don't stop!

"An Indonesian tribesman whose native starches were root vegetables cried after eating white rice for the first time and when questioned stated that it was because he'd never have it again. He wasn't conditioned to enjoy his native foods, it just was all he had."

This illustrates the body's instinctive quest for energy, not an instinct for what is optimal.  If that person was given access to as much white rice as they wanted, they might have abandoned their traditional way of eating in favor of their instinctual drive for energy and wound up with beriberi and other nutrient deficiencies.  That's definitely happened to other people, and it's a common theme among indigenous peoples introduced to western diets that they acquire nutrient deficiencies and chronic disease.

"It's definitely possible for us to adjust to foods that go against our instincts to a degree but it's normally a learned behavior in order to survive rather than thrive due to the said food providing some unique nutritional or medical benefit however when it comes to macronutrient balance the body always wants plenty of protein, fat AND carbs.

I've tried to enjoy liver many times but never could which makes sense because it doesn't provide me with any unique nutritional benefit yet it contains toxic levels of vitamin A."

The body requires glucose to function properly.  It can generate that glucose from other substrates, or it can acquire it directly from food.  It doesn't want carbohydrates per se...it wants energy.  That energy can come from protein, fat, or carbs, each of which has some tradeoff for energy production.  If availability is unlimited, fat appears to be the optimal source of energy, followed by carbs. 

Liver does provide much higher quantities of some nutrients by weight (in a more bioavailable form) than other foods, without also containing overt toxins.  To me, it's abundantly clear that Vitamin A is not a toxin, but like anything else can become harmful in excessive amounts, however we might define excessive.  Indigenous cultures that sanctify liver should have died out long ago if the liver was toxic to consume.

"You seem unclear about what I wrote. Many neolithic populations certainly could have developed adaptations to both conserve vitamin A and to minimize excretion, paleolithic peoples may have been more equipped to process vitamin A. However, it wasn't impossible to consume a paleolithic low vA diet at all, in fact there is documented evidence that I've previously posted showing that even hunter gatherers suffered from xeropthalmia and knew of liver as a cure (implying that for many it wasn't a part of their normal diet). Many of them didn't consume many carotenoids and they didn't have dairy so if they didn't eat liver the diet was not high in vitamin A."

I'm not sure which hunter-gatherers you're referring to, but I would make a hefty wager that natural selection has had to select against Vitamin A toxicity much more than deficiency.  Life is all about efficiency.  Every animal (humans included) is faced with limited resources, and those who survive and reproduce are more likely to be efficient at making use of those limited resources.  Humans unambiguously evolved to hunt animals.  It takes energy to hunt an animal, and energy is a limited resource.  Once you get an animal, you want to maximize the energy derived from it.  Liver is a very easy thing to extract and digest.  Hence, it is reasonable to expect that humans would have evolved eating a lot of liver and Vitamin A on a regular basis.  Considering how easy it is for modern humans to become toxic with Vitamin A, it would appear that even paleolithic humans would be more likely to struggle with toxicity than deficiency, and would therefore have more pressure to evolve methods of excreting Vitamin A efficiently rather than conserving it.  The incidence of xerophthalmia sounds like an anomaly unless there's evidence that it was widely prevalent among other groups of people. 

Quote from tim on May 1, 2021, 9:11 pm

@wavygravygadzooks

Our basic instincts lead us to protein, fat, and carbohydrates and steer us away from toxins, but instincts aren't foolproof.  Do you think kids that gorge on candy are doing themselves good?  They're responding to an instinct for carbohydrate consumption, but they require cultural input and learned experience to keep them from routinely overconsuming empty calories.

You're mixing an instinct that serves to sustain with instincts that serve to protect. The instinct for sugar works fine in a natural environment where honey takes effort to collect. The instinct to protect against toxins still works fine in an unnatural environment which is why children can eat too much sugar but are good at protecting themselves from food toxins.

You may have an aversion to liver because of the high copper content if your body is already full of copper, which may be your body's instincts serving you well.  Or you may have an aversion to liver simply because you've not eaten it regularly and your body at its age has developed a wariness of new foods.

MOST people have an aversion to liver and it's not because of how copper toxic they are. Most people like chocolate, nuts and other foods rich in copper but hate liver.

We don't have taste receptors for Vitamin A, and there's apparently no instinct to avoid either carotenoids or preformed Vitamin A even when we're toxic.

We don't need to have an aversion for vitamin A, we just need to have an aversion for foods that are high in it. This is one reason why supplements can be problematic.

I'm in my mid 30's and I didn't eat any fresh liver until the past couple years.  When I did start eating it, I thought it was delicious, although I could detect some mild bitterness in it (I think it's probably the copper I was tasting).  I was already badly Vitamin A toxic, and I definitely was not deficient in copper, yet my body's instincts were signaling to me that this was an appropriate thing to eat.  How would you make sense of this?

There is variation in how averse we are to problematic foods. Most people hate liver. Most children dislike a range of vegetables. Some children like liver and all vegetables. Those of us with weaker instincts are more likely to run into problems. We're so conditioned to think that discriminating eaters are the problem when it's actually undiscriminating eating that's more of an issue.

All this anecdote suggests is that your dog might have been nutrient deprived from an unnatural diet (dogs that consume feces of any kind are potentially nutrient deprived).  I don't know what you were feeding it, but if it was commercial dog feed, you could argue that your dog became habituated to eating dog "food" even though it was not an instinctual diet.  As for fruit, canines are facultative carnivores, they largely depend on animal meat and fat for survival.  Some of them will eat wild fruit, but the fact that a domesticated canine didn't like mutant fruit cultivated by humans doesn't say much about the instincts or behavior of animals.

My dog ate mostly organic beef, dogs in the wild like the intestines of animals afaik. Commerical dog food often has flavour enhancers afaik to make it more palatable? The fact that she didn't eat fruit but liked poop was just a simple demonstration of how instinctual food selection is.

Are you referring to the Shackleton expedition?  My wife just happens to be reading about that right now...they were burning the fat to cook the meat!  They were probably approaching rabbit starvation by subsisting mostly on lean meat, so of course they're going to be craving glucose when they're rescued.

You seem to be ignoring the fact that the instinctive response of these men was to NOT eat seal.  If anything, they were repulsed by it, even though it was a nourishing food.  They had to override their instinctual revulsion of something that saved them, and the reason it saved them is because it had considerable nutritive quality.

Most of the Inuit who have been provided access to high energy processed foods have experienced deteriorating health, yet their instincts do not stop them from continuing to eat that food.  Their instincts tell them easy calories = good, don't stop!

No it was a shipwreck south of NZ. They had other meats and eggs and there was plenty of blubber on the seals and sea lions. They were not starving to death. The dinner laid out for them had a variety of nice foods but they went crazy for the fresh bread. When I tried very low carb for a while years ago and then ended it it was a similar effect, carbs were so delicious, fat is not a substitute for carbs lol.

Inuit were not free from disease like some believe and they have genetic adaptations to the diet they consumed.

This illustrates the body's instinctive quest for energy, not an instinct for what is optimal.  If that person was given access to as much white rice as they wanted, they might have abandoned their traditional way of eating in favor of their instinctual drive for energy and wound up with beriberi and other nutrient deficiencies.  That's definitely happened to other people, and it's a common theme among indigenous peoples introduced to western diets that they acquire nutrient deficiencies and chronic disease.

The point I was making was that he wasn't heavily conditioned to like his native diet. White rice is a health promoting food, you're mixing up excess consumption with simply having it in the diet. Beriberi typically affects poorer people that do not have much access to meat and fat and over consume polished rice to a much greater degree than if they had access to a more varied diet.

The body requires glucose to function properly.  It can generate that glucose from other substrates, or it can acquire it directly from food.  It doesn't want carbohydrates per se...it wants energy.  That energy can come from protein, fat, or carbs, each of which has some tradeoff for energy production.  If availability is unlimited, fat appears to be the optimal source of energy, followed by carbs. 

That's exactly why we love starch so much, protein is a highly inefficient source of glucose. Saturated and monounsaturated fats are very important energy sources and they can easily be generated from carbs but not vice versa.

Liver does provide much higher quantities of some nutrients by weight (in a more bioavailable form) than other foods, without also containing overt toxins.  To me, it's abundantly clear that Vitamin A is not a toxin, but like anything else can become harmful in excessive amounts, however we might define excessive.  Indigenous cultures that sanctify liver should have died out long ago if the liver was toxic to consume.

Many hunter gatherer groups knew of xeropthalmia and understood that liver consumption was the cure which means that many were not routinely consuming it as a normal food item. Most of us here though are not immediately descended from hunter gatherers anyway and it's likely that there is a lot of variation in vitamin A tolerance around the world.

I'm not sure which hunter-gatherers you're referring to, but I would make a hefty wager that natural selection has had to select against Vitamin A toxicity much more than deficiency.  Life is all about efficiency.  Every animal (humans included) is faced with limited resources, and those who survive and reproduce are more likely to be efficient at making use of those limited resources.  Humans unambiguously evolved to hunt animals.  It takes energy to hunt an animal, and energy is a limited resource.  Once you get an animal, you want to maximize the energy derived from it.  Liver is a very easy thing to extract and digest.  Hence, it is reasonable to expect that humans would have evolved eating a lot of liver and Vitamin A on a regular basis.  Considering how easy it is for modern humans to become toxic with Vitamin A, it would appear that even paleolithic humans would be more likely to struggle with toxicity than deficiency, and would therefore have more pressure to evolve methods of excreting Vitamin A efficiently rather than conserving it.  The incidence of xerophthalmia sounds like an anomaly unless there's evidence that it was widely prevalent among other groups of people.

Just because food was scarce does not mean we made adaptations to excrete large amounts of vitamin A. Carnivores are also prone to Hypervitaminosis A and they are much better equipped to excrete it e.g. short guts and low fecal transit time. Regardless, like I said, we aren't paleolithic humans anymore.

Quote from lil chick on May 2, 2021, 8:04 am

Personally I don't want it to be true that we can't rely on our taste buds to lead us.   Just as I don't want it to be true that we are meant to be eventually poisoned by VA in order to reduce the surplus population (as one or two have mused).

I do feel like our tastes and food desires might be quite muddled LOL.  It might take some effort to hear them again.

Quote from wavygravygadzooks on May 2, 2021, 2:48 pm

@tim-2 So, you're arguing that we're not paleolithic humans anymore, and therefore we can't apply the same principles from pre-historic living to the modern era, yet we should still rely on our paleolithic instincts even though they are known to lead us astray in the modern environment...and you see no contradiction in that?

How do you know people's aversion to liver is not related to copper status?  By weight, raw liver has over 4 times as as much copper as any of the common nuts or dark chocolate, and the nuts and chocolate also have more fat, and likely more carbs, than liver, which means our desire for fat and simple carbs may be masking any distaste for the other components of the nuts and chocolate (which include a lot of defensive compounds).  We're much more likely to eat something bitter (e.g. salad) when we cover it in fat (oil/cheese) and carbs (croutons, fruit, sugary dressing).  Additionally, almost everyone today is raised on a plant-based diet, which has a much higher copper:zinc ratio than an animal-based diet, so it is reasonable to expect that most people attempting to eat liver today are already somewhat high in copper.

I agree that there is going to be some variation in taste among individuals, partially due to genetics and an individual's detoxification pathways, and partially due to environment/culture.

Wild canids are more likely to eat the small intestines (which do not contain fecal matter) than the colon, but they'll eat just about any part of the animal when they're hungry enough.  Hunter-gatherers generally do the same.

White rice is a health-promoting food?!  As someone who practically subsisted on white rice for 10 years (alongside healthy portions of meat at every meal), I can tell you it gives you a lot of energy and a lot of energy crashes, and it promotes dysbiosis and malnourishment.  I practically had to have a rice IV line, I was eating every hour or two.  Eating that frequently is not natural, and not healthy.  Sure, having a small amount of white rice is probably fine, but you have to get the rest of your calories from somewhere...  If you're going to have to eat some fat to maintain normal metabolism, you might as well max out your fat intake and only eat once or twice a day, giving your digestive and endocrine system a break and freeing you up to do other things with your time than constantly search for starch/sugar. 

Pre-historic humans were opportunists, just like every animal.  They had the ability to metabolize carbs easily, and if there were some accessible, why wouldn't they eat them?  But they weren't constantly accessible, and humans needed protein from animals, so they spent a lot of time hunting animals.  And if you're going to spend most of your time hunting animals, then your diet is going to be primarily comprised of what's on an animal, which is protein and fat with a tiny amount of carbs.

While it is true that the conversion of carbs to energy is slightly more efficient than converting fat to energy, that is only a small part of the whole picture.  Humans store carbs as fat because it's the only way we can carry around all the energy we need.  We can use fat directly for most of our energy demands, so we don't need to convert fat to carbs.  A carb-based diet leads to water retention, which means you're carrying around extra weight, which requires extra energy to move and puts additional strain on your joints.

Natural selection pushed early humans toward specialization in hunting animals.  Once that happened, the pattern kept reinforcing itself, due to increasing energetic demands of the brain and stomach.  Once you become dependent on animals, it makes very little sense energetically to seek out small sources of energy (plants) that are scattered across the landscape and require lots of time to gather and digest.

Among animals, there are essentially plant specialists (herbivores) and animal specialists (carnivores and omnivores).  So-called omnivores are usually meat-eaters with varying abilities to find and digest plant material, but they typically can't survive indefinitely on plant material, whereas they could survive solely on animals if they had the ability to capture them whenever needed.  Omnivores, including humans, basically have a buffer against starvation in the absence of animal food.  Were it not for agriculture, there is no way we could get enough carbs to sustain our energy demands.  And although there has been some adaptation to an agrarian lifestyle, the optimal diet for humans is still the pre-agriculture diet that is mostly animal (protein and fat), as evidenced by our physiology.