tag:blogger.com,1999:blog-5995754777906978314.post1625543324676548373..comments2023-10-20T05:56:15.365-07:00Comments on Evolving Health: Why you can all stop saying meat eating fueled evolution of larger brains right nowdaviddespain.secrethttp://www.blogger.com/profile/13271527839470084409noreply@blogger.comBlogger23125tag:blogger.com,1999:blog-5995754777906978314.post-53982859694387837052013-01-12T10:06:11.773-08:002013-01-12T10:06:11.773-08:00OK, let's take animal products out of the equa...OK, let's take animal products out of the equation and restrict early humans to only plants and cooking. Do early humans evolve into us....? Perhaps, but it seems like the inclusion of animal products became the catalyst of our large brains. So this would support your assertion that broadening our diet was key, but it was the expansion into animal products that was critical.Teechhttps://www.blogger.com/profile/16578812444690989223noreply@blogger.comtag:blogger.com,1999:blog-5995754777906978314.post-57371708194636581122012-12-12T09:41:55.337-08:002012-12-12T09:41:55.337-08:00I have one complaint to raise in regards to Wrangh...I have one complaint to raise in regards to Wrangham and the other study mentioned wrt comparisons between modern primate's diets and the energy needs of modern humans, typically concluding that we would have to spend the majority of our waking lives eating if not for cooking.<br /><br />Chewing raw meat is not nearly so slow and difficult if basic stone tools are used for some pre-processing, and human cranial morphology has been shown to be more suited to shearing than crushing (opposite to extant apes), which makes a chimp chewing all day on a monkey carcass a poor parallel.<br /><br />Perhaps more significantly, little consideration is made for human's greater capacity to access high-calorie fat-rich tissues such as brain and marrow using stone tools. <br /><br />The presence of now-extinct megafauna (typically with greater fat stores) and involvement of shore foods also seems to escape consideration. It makes little sense to assume an identical food environment.<br /><br />To be clear, I agree that cooking likely played a vital role in increasing nutrient availability for our ancestors but the methodology used in cases such as that recent study or arguments put forth in "Catching Fire" have the potential to greatly exaggerate the case. <br /><br />Observations of modern raw foodists also tend to be a poor argument as so much of that movement is driven by preexisting health issues, eating disorders and psychological issues. There do seem to be at least some raw foodists with good health and body mass, who typically incorporate lots of fatty tissue and fermentation techniques and so it is unclear whether our ancestors could have successfully sourced such diets, but as there is no real study on such subjects as of yet I would suggest that the subject as a whole is not a good source of evidence wrt cooking vs. non-cooking.Erikhttps://www.blogger.com/profile/09965863238694382738noreply@blogger.comtag:blogger.com,1999:blog-5995754777906978314.post-69783227623217066032012-12-05T15:48:04.864-08:002012-12-05T15:48:04.864-08:00It bears disambiguating the terms "ketosis&qu...It bears disambiguating the terms "ketosis" and "ketogenesis", because the concept of being in a ketogenic state leading to ketoacidosis is a misunderstanding.<br /><br />Ketosis is the state of generating excess ketones, such that you can observe the excess being eliminated through the urine.<br /><br />In a state of ketogenesis, an individual only produces as many ketone bodies as necessary, and very few, if any, ketone bodies will be observed in urine.<br /><br />Thus the general progression of a person on Atkins is that they go into ketosis because their body needs to adapt and become more efficient at this type of metabolism, and over the course of days or weeks or sometimes months (depending on the individual), you see the ketone bodies decrease in urine.<br /><br />The standard line in traditional medical literature about ketoacidosis being a danger of being in ketosis is technically correct.<br /><br />But it's only people in a diseased state (such as diabetes) who end up in constant ketotic overflow, because failing to "keto-adapt" (as Drs Volek and Phinney would put it) is a symptom of metabolic dysfunction -- not an inevitability.nthmosthttps://www.blogger.com/profile/10241248641661243071noreply@blogger.comtag:blogger.com,1999:blog-5995754777906978314.post-36665395886464693132012-12-05T15:42:07.489-08:002012-12-05T15:42:07.489-08:00I think we're rounding off to nearly the same ...I think we're rounding off to nearly the same conclusion, that it was the discovery of a method of exposure of more nutrients from food (i.e. cooking and maybe other tool use) that allowed the brain to continue expanding its volume in our evolution.<br /><br />So the following is just nitpicking at this point:<br /><br />"But the brain itself is different -- ketones will only replace glucose use only after long periods of starvation. That's a nice adaptation when food is scarce that I'm not discounting, but it's not really ideal long-term (also since ketone accumulation can lead to ketoacidosis). I wouldn't consider that "efficient". Here's the thing: I certainly understand that a ketogenic diet might have some uses (such as in epilepsy) or even for weight loss. "<br /><br />That's definitely what the biochemistry and nutrition textbooks will tell you.<br /><br />But it's also a "Just So Story" about the reasons why this mechanism exists.<br /><br />What's interesting is that the biochemical milieu of what's called "starvation" is almost identical to that of "nutritional ketosis", in which the body really is not starving. An individual can be getting ample calories from fat and protein and be in this so-called "starvation" state, from a hormonal profile perspective.<br /><br />We only see this state as an aberration because nowadays, a person generally has to choose to go into a ketogenic state (e.g. following an Atkins style diet), whereas -- if some paleolithic theorists are to be believed -- periods of obligate ketogenesis were endemic to the Paleolithic condition due to fluctuating food availabilities.<br /><br />And again, ketogenesis really isn't inefficient. Emily Deans, MD, argues that it appears that the use of ketones to power the brain is *more* efficient, since there are fewer byproducts of metabolism, and there are no noticeable downsides to fueling the brain in this way.<br /><br />You're taking the perspective that ketogenesis is inefficient because in our modern food economy, it's a rare state to be in, and thus our adult bodies will take a few days or weeks to adapt fully to the use of ketones.<br /><br />But it's useful to note that newborns come into this world in a state of ketogenesis, and while they are breastfeeding they fluctuate in and out of ketogenesis pretty effortlessly.<br /><br />So it seems disingenuous to call ketogenesis a state of "starvation", to imply that it's an aberrant condition and assign a negative connotation to it.<br /><br />It makes more sense (to me) to say that we are born with a metabolic flexibility to survive equally well on sugar and on fat as our primary fuel source, and that the ubiquity of glucose in our everyday lives removes us from that flexibility.nthmosthttps://www.blogger.com/profile/10241248641661243071noreply@blogger.comtag:blogger.com,1999:blog-5995754777906978314.post-27526882476853481202012-12-05T15:39:47.652-08:002012-12-05T15:39:47.652-08:00This comment has been removed by the author.nthmosthttps://www.blogger.com/profile/10241248641661243071noreply@blogger.comtag:blogger.com,1999:blog-5995754777906978314.post-65967939820134317742012-12-05T09:57:49.392-08:002012-12-05T09:57:49.392-08:00nthmost, Zooko, and others,
For my readers' s...nthmost, Zooko, and others,<br /><br />For my readers' sakes, I want to explain a little more about ketone bodies. Ketones are products of fat catabolism. That's to say when your cells stop burning glucose, fat is mobilized from adipose tissue, it's broken down and ketones are used as fuel for several tissues. For example, muscles will often use ketone bodies to spare their amino acids from being used to synthesize glucose. But the brain itself is different -- ketones will only replace glucose use only after long periods of starvation. That's a nice adaptation when food is scarce that I'm not discounting, but it's not really ideal long-term (also since ketone accumulation can lead to ketoacidosis). I wouldn't consider that "efficient". Here's the thing: I certainly understand that a ketogenic diet might have some uses (such as in epilepsy) or even for weight loss. <br /><br />Yet, in regards to evolution of larger brains, I'll point out again that the experts suggest there's certainly reasons for four times more glucose entering the brain (beyond glucose's scarcity) and that is more likely what helped fuel larger brains. Consider, for example, children with Glut1 deficiency syndrome (a deficiency in glucose transporters in the brain). They certainly show cognitive deficits. As Wray explains in my earlier post, "the brain literally starves" in a child with this syndrome.<br /><br />In his talk, Wray suggests meat eating may have played a role too because of extra fatty acids provided for brain development. Other experts suspect meat played a role, too. Although, as pointed out here, Wrangham says cooking was most important and Herculano-Houzel (a neuroanatomist who's written heavily on the topic of brain metabolism!) does too. <br /><br />Bottom line: it's probably more appropriate to say "broadened diet" or "cooking" played the greater role post 2mya (ancestral humans were already hunting by around 2mya) for increases in cranial size and it was likely due to more glucose. <br /><br />David daviddespain.secrethttps://www.blogger.com/profile/13271527839470084409noreply@blogger.comtag:blogger.com,1999:blog-5995754777906978314.post-17115197664481637772012-12-04T21:36:21.412-08:002012-12-04T21:36:21.412-08:00"We also have four times more capability at g..."We also have four times more capability at getting glucose across into the brain in comparison to chimps, as per Duke biologist Greg Wray. That certainly should be evidence to the role of glucose in fueling our brains despite limited gluconeogenesis..."<br /><br />That glucose played a *role* in human evolution seems much closer to the truth here.<br /><br />Maybe the reason we're four times more efficient than chimps at processing glucose across the blood-brain barrier is because glucose was a rare and precious nutrient.<br /><br /><br />"... and inefficient ability to use ketones."<br /><br />I think Drs Volek and Phinney would debate you on that.<br /><br />Again, there's this concept of a keto-adaptation period that a lot of researchers and theorists seem to be ignorant or dismissive of, so it's not surprising (as Zooko alluded) that the argument would be that fats couldn't possibly fuel the brain "efficiently".nthmosthttps://www.blogger.com/profile/10241248641661243071noreply@blogger.comtag:blogger.com,1999:blog-5995754777906978314.post-2459174520294607592012-12-03T09:25:09.442-08:002012-12-03T09:25:09.442-08:00Barbara King from NPR blogged about this blog post...Barbara King from NPR blogged about this blog post http://www.npr.org/blogs/13.7/2012/12/02/166360654/carbs-not-meat-fueled-evolution-of-the-enlarged-human-brain?guid=1354552380257<br /><br />I have responded to a couple of the comments there, including one from Peter who once again pointed out that ketones and gluconeogenesis could contribute energy to the brain. I'm republishing my response here: <br /><br />Peter,<br /><br />You are not the only person who's pointed out that I didn't address ketones. Perhaps, more also needs to be said about gluconeogenesis. I've addressed this question on my own blog comments and may even need to write another blog post.<br /><br />Of course, I'm well aware that the brain is capable of using ketones and that gluconeogenesis can supply extra glucose, but I'll point out that these are inefficient processes with limitations and their own metabolic costs in terms of ATP. In short, the argument here is mainly that, because of 86 billion neurons (3x more than chimps) that prefer glucose, even top experts in evolution of the human diet -- anthropologist Peter Ungar, biological anthropologist Richard Wrangham, and comparative neuroanatomist Suzana Herculano-Houzel don't necessarily buy into the theory that meat eating was the primary driver that fueled evolution of the human brain. The way meat did play a role was in freeing up glucose calories. And it's more likely, per the experts, that a "broadened niche" and cooking probably had a lot more to do with our ability to fuel increases in brain size than did meat.<br /><br />We also have four times more capability at getting glucose across into the brain in comparison to chimps, as per Duke biologist Greg Wray. That certainly should be evidence to the role of glucose in fueling our brains despite limited gluconeogenesis and inefficient ability to use ketones.<br /><br />Lastly, I'll refer you to a relatively recent research article of Suzana Herculano-Houzel, who I mention in my article, but who I didn't quote. In her article, she discusses the metabolic costs of our 86 billion neurons, and how cooking evolution of the human brain may have only been possible through cooking freeing up calories from meat and starches alike. http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0017514daviddespain.secrethttps://www.blogger.com/profile/13271527839470084409noreply@blogger.comtag:blogger.com,1999:blog-5995754777906978314.post-11589249280737731472012-12-03T07:49:11.939-08:002012-12-03T07:49:11.939-08:00> The argument made here is meat eating and glu...> The argument made here is meat eating and gluconeogenesis were probably not enough to power evolution of larger brains (except in that it freed up glucose for use in the brain)<br /><br />Hi David. There are two problems packed into that sentence. ☺ First, the argument that carnivory was insufficient to power the evolution of larger brains is undermined by the fact that carnivory is sufficient to power the operation of the modern human brain! Now, there could be some reason why some other food source was necessary, or at least helpful, for the evolution of large brains even though it is not necessary for the modern maintenance of same, but that would be a more complicated argument. The simple argument that you seem to be making is:<br /><br />1. Eating meat alone is insufficient to power the human brain.<br />2. Therefore the evolution of large brains must have been caused by something other than eating meat.<br /><br />That simple argument is incorrect because its first premise (1) is incorrect.<br /><br />Note that it is entirely possible that the scientists that you interviewed (Ungar, Wrangham, Herculano-Houzel) are confused about this. It is an ill-understood area right now and it is common for people to incorrectly state that meat-eating is insufficient to power the human brain.<br /><br />The second problem in your sentence above is "(except in that it freed up glucose for use in the brain)". Whether that mechanism was or was not part of the process by which meat-eating caused the evolution of larger brains is irrelevant to the question of whether <i>or not</i> meat-eating caused the evolution of larger brains!<br /><br />If meat-eating caused the evolution of larger brains, and if it did so by freeing up glucose for use in the brain, then so be it. That doesn't make any less the cause of the change, does it?Anonymoushttps://www.blogger.com/profile/17046522562803939443noreply@blogger.comtag:blogger.com,1999:blog-5995754777906978314.post-46501739864202564632012-12-03T00:55:51.148-08:002012-12-03T00:55:51.148-08:00Question: I tend to believe your arguments that pr...Question: I tend to believe your arguments that proteins, and esp raw meat, are not a good source of energy. But I don't get the connection to brain size. The primary relevant factor for brain growth is survival. For that you need sufficient energy intake, alright, but how to achieve that is influenced by many other factors. It might well enough be that proteins play a relevant role for other physiological changes that were beneficial for survival, which is correlated with brain growth without being a direct causation. Does that seem possible?Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-5995754777906978314.post-67208046675943441152012-12-02T23:30:48.190-08:002012-12-02T23:30:48.190-08:00Emily Deans posted a good article about evidence, ...Emily Deans posted a good article about evidence, from a psychiatric point of view, that the human brain functions better on keytones than glucose:<br /><br />http://evolutionarypsychiatry.blogspot.ca/2010/08/your-brain-on-ketones.htmlBrent Kearneyhttps://www.blogger.com/profile/11771241613580746870noreply@blogger.comtag:blogger.com,1999:blog-5995754777906978314.post-9836113075674760722012-12-02T23:26:14.660-08:002012-12-02T23:26:14.660-08:00A quick note about gluconeogenesis and ketones:
...A quick note about gluconeogenesis and ketones: <br /><br />There have been several comments suggesting that I've left out the role of gluconeogenesis from amino acids and use of ketones in the brain for energy. Yes, they can assist in brain function -- no one is arguing otherwise. <br /><br />The argument made here is meat eating and gluconeogenesis were probably not enough to power evolution of larger brains (except in that it freed up glucose for use in the brain), as argued by top experts on the evolution of the human diet Peter Ungar and Richard Wrangham, and Suzana Herculano-Houzel. <br /><br />Partly, that's probably due to limitations of gluconeogenesis in humans and limitations of use of ketones in some 86 billion neurons 24x7. So, a broadened niche of some kind was needed and that probably resulted from cooking. <br /><br />I'm sensing some confusion along these lines, so perhaps I'll need to revisit in a future post. daviddespain.secrethttps://www.blogger.com/profile/13271527839470084409noreply@blogger.comtag:blogger.com,1999:blog-5995754777906978314.post-78782144503578316052012-12-02T20:50:01.144-08:002012-12-02T20:50:01.144-08:00You don't need DIETARY glucose or DIETARY carb...You don't need DIETARY glucose or DIETARY carbohydrates of any kind to provide glucose to the BRAIN. <br /><br />http://en.wikipedia.org/wiki/GluconeogenesisBone Daddy Dawghttps://www.blogger.com/profile/14875466587598200902noreply@blogger.comtag:blogger.com,1999:blog-5995754777906978314.post-73130428406894905972012-12-02T19:41:47.902-08:002012-12-02T19:41:47.902-08:00I think there are some mistakes in this argument.
...I think there are some mistakes in this argument.<br /><br />First of all, you say that neurons run exclusively on glucose, but according to Volek and Phinney (http://www.amazon.com/The-Art-Science-Carbohydrate-Living/dp/0983490708/ref=pd_bxgy_b_img_y), the brain uses glucose for only about 1/3 of its fuel in the keto-adapted state.<br /><br />But the bigger mistake is inferring from the fact that the brain depends on glucose to the belief that the organism depends on eating carbohydrates. That doesn't follow, because gluconeogenesis is more than sufficient to provide the necessary blood glucose. You mention gluconeogenesis, but I didn't understand why you are discounting it as a mechanism for fueling the brain.<br /><br />As far as I can tell, I can continue saying that meat-eating (and/or fire) probably fueled the evolution of larger brains.Anonymoushttps://www.blogger.com/profile/17046522562803939443noreply@blogger.comtag:blogger.com,1999:blog-5995754777906978314.post-53107950754998538702012-12-02T18:02:48.776-08:002012-12-02T18:02:48.776-08:00i've read, or read of, a paper where brain glu...i've read, or read of, a paper where brain glucose uptake actually increases in ketotis - fat-burning shift in muscles etc means more of the blood glucose is available to the brain. Which would match a higher-fat<br />diet fueling brain growth.<br />However other primates also eat high-fat once fibre is fermented - but they need the bigger gut to do this.<br />A combination of increasing cooking of carbs and sparing the gut by eating meat and fat and nutrient-rich organs, the two needn't be contradictory.Puddleghttps://www.blogger.com/profile/00953398103675945541noreply@blogger.comtag:blogger.com,1999:blog-5995754777906978314.post-21383243034865690732012-12-02T17:27:24.389-08:002012-12-02T17:27:24.389-08:00Man, you got me all excited about maybe some new r...Man, you got me all excited about maybe some new research or something, but this is nothing new.<br /><br />I've read this "we need glucose to fuel the brain" argument before, and it's pretty easily refuted by the fact that, after a relatively short adaptation period during which the individual consumes little to no carbohydrate (e.g. during a period in which hunting is going well but there are no starches or fruits to be found), the brain reduces its need for glucose by quite a bit and replaces that requirement with ketones.<br /><br />Under those keto-adaptive conditions, the brain is kept well fueled by the small amount that can be easily provided by gluconeogenesis, and the cells of the body become far more efficient over time at utilizing ketones.<br /><br />(See the Art and Science of Low Carbohydrate Performance by Jeff Volek, PhD, and Stephen Phinney, MD PhD.)<br /><br />As for the fetal brain, it's constructed by ketones, actually.<br /><br />http://www.ncbi.nlm.nih.gov/pubmed/1206409<br /><br />http://www.ncbi.nlm.nih.gov/pubmed/927049<br /><br />So, I still don't get it: why is the brain the reason why the paleo diet had to have been even moderately high in carbs? Or contain carbs on a regular basis?<br /><br />I get why carbs are good for the body stochastically (normalization of thyroid hormones, for starters), but I still am not convinced that carbs had to be the reason why the human brain evolved.nthmosthttps://www.blogger.com/profile/10241248641661243071noreply@blogger.comtag:blogger.com,1999:blog-5995754777906978314.post-43631238211094641582012-12-02T17:22:19.169-08:002012-12-02T17:22:19.169-08:00This comment has been removed by the author.nthmosthttps://www.blogger.com/profile/10241248641661243071noreply@blogger.comtag:blogger.com,1999:blog-5995754777906978314.post-37957566559207453142012-12-02T17:20:57.488-08:002012-12-02T17:20:57.488-08:00This comment has been removed by the author.nthmosthttps://www.blogger.com/profile/10241248641661243071noreply@blogger.comtag:blogger.com,1999:blog-5995754777906978314.post-78485580303292710782012-12-02T17:12:20.555-08:002012-12-02T17:12:20.555-08:00AWESOME David!AWESOME David!CarbSanehttps://www.blogger.com/profile/17739915307890592327noreply@blogger.comtag:blogger.com,1999:blog-5995754777906978314.post-84278881234033339062012-12-02T16:55:28.438-08:002012-12-02T16:55:28.438-08:00In humans, the first milk (colostrum) which is ava...In humans, the first milk (colostrum) which is available for the first 5-7 days is relatively high in protein: 2.3g compared to mature milk which is 0.9g <br /><br />Fats as a whole go from 2.9 mg to 4.2 and lactose from 5.3g to 7.0g as we switch from colostrum to mature milk. <br /><br />(numbers in literature vary partly because human milk varies from woman to woman, within a feed & with time of day - but these are from current lit) <br /><br />So big protein push at beginning of extrauterine life, then we switch to being fuelled more by carbs. <br /><br />There has been some interesting research about protein deprivation in pregnancy causing negative effect on brain development but I think the link is with alterations to maternal lipid metabolism. LC PUFA's are critical for the developing brain. <br /><br />regards, from an International Board Certified Lactation Consultant (& vegetarian)hornblowerhttps://www.blogger.com/profile/11428146299208610591noreply@blogger.comtag:blogger.com,1999:blog-5995754777906978314.post-27520220081557427382012-12-02T15:51:09.895-08:002012-12-02T15:51:09.895-08:00"Glucose is the dominant oxidative fuel for b..."Glucose is the dominant oxidative fuel for brain, but studies have indicated that fatty acids are used by brain as well." In this paper, about 20% of brain energy is from lipids:<br />http://www.jneurosci.org/content/23/13/5928.short<br />lactate from muscles seems to be the first brain fuel for newborns before suckling: http://www.ncbi.nlm.nih.gov/pubmed/2998491 <br />ketones are used to make brain lipids:<br />http://www.ncbi.nlm.nih.gov/pubmed/6487643<br /><br />Another way in which primate brains secured more glucose is by no longer converting it to ascorbate.<br />Glutamine and aspartate are amino acids that are easily converted to glucose.<br />Much of energy for growing brain comes from dietary fat, which is why milk is full of SFAs: http://sphotos-d.ak.fbcdn.net/hphotos-ak-snc7/417019_513098665375563_1634613470_n.jpg<br />Galactose also contributes.Puddleghttps://www.blogger.com/profile/00953398103675945541noreply@blogger.comtag:blogger.com,1999:blog-5995754777906978314.post-34037507701101885432012-12-02T15:10:26.688-08:002012-12-02T15:10:26.688-08:00I have a question. You point out that carbs are mo...I have a question. You point out that carbs are more important than protein for running a brain, but is that also true for building a brain? What is most important for a developing fetus or small child? John McKayhttps://www.blogger.com/profile/08687505203164692983noreply@blogger.comtag:blogger.com,1999:blog-5995754777906978314.post-57440405544644679112012-12-02T15:09:46.955-08:002012-12-02T15:09:46.955-08:00This comment has been removed by the author.John McKayhttps://www.blogger.com/profile/08687505203164692983noreply@blogger.com