About a year and a half ago I decided to get serious about my health. The primary reason had to do with the fact that I have children, and I wanted to reduce my risk of mortality as well as morbidity (yes, I have life insurance). A more specific reason to me is that for years my blood sugar has been on the high end of normal. Not pre-diabetic, but too close for my comfort. This is not abnormal for South Asians. And, my father developed type 2 diabetes around my current age (some context, he’s 4 inches shorter than me, and was a bit heavier and much paunchier than I’ve ever been). Within a combination of lifting and running, and mild changes to how I eat (more “Paleo”, though I’m not strict about it), I’ve gone from 155-160 lbs to 145-150 lbs (I’m 5’8). My body fat has gone from ~20% to ~15% from April 2014, to right now.

But I still have a distance to go. I want to push my body fat percentage closer to ~10%. Part of it is health, but at this point much of it is aesthetic. A friend of mine finds this all quizzical, since I haven’t been single in more than 10 years. But then again, he’s single, so what does he know about motivations? The reality is that everyone is not beautiful, and that almost everyone can get more beautiful. And that’s a good thing, and not just because it’s a social construct. Eating junk food and being lazy feels good too. But it doesn’t make you feel good about yourself.

The low hanging fruit is gone. At this point I’m running about 3.5 to 4.0 miles 4-5 days a week, and hitting the weights a similar number of days. Though I think I’m making slow but steady progress, I’m worried that I’m trying to do too much. E.g., am I running so much that I’m losing muscle mass? (I’m starting to suspect this) Do I need to eat more? Do I suffer from low T? There are lots of questions I have.

Of course you can go to bodybuilding.com and “get all the answers.” But you then know how that goes. Next there are informative websites like Skinny-Fat Transformation. What’s one to believe? I believe in personal experimentation, so I think I can get there by iterating. But it’s a tough haul, and I’d like to cut a few corners. (though one thing that’s consensus is that pull-ups are good)

So I’m putting this post up mostly to get reader feedback. My ultimate goal is to get down to the body fat percentage above, and gain definition. I’m not aiming for a lot of bulk. I’m only 5’8, and I don’t want to turn into what I like to term the “brick-guys” (the guys build like bricks). What’s worked for you? What’s not? People of South Asian ancestry especially would be useful.

Note: I have a very young looking face and my skin hasn’t aged much at all, so one issue that I suspect I have is a lot of subcutaneous fat. My suspicion is that this means that it’s not easy for me not to look smooth and fatty.

A friend sent me a link to this long piece in The New Republic, What’s a species anyways?. Its subtitle is “The search for the red wolf’s origins have led scientists a new theory about how evolution actually works.” This is wrong. In fact, the article itself admits that there’s nothing revolutionary here. You just need to get to the second half of the piece, where the truth, as opposed to sensationalism, steps front and center. Many types of biologists have different ideas about what a species is. Often they are divided by disciplinary focus; phylogeneticists have different priorities than evolutionary geneticists. My friend John Wilkins wrote a book on the issue, top to bottom, Species: A History of the Idea. John’s a philosopher of science, so he has a precise take. Working biologists are often not so clear, and that’s sort of the point. In Speciation, a book co-written by two evolutionary geneticists (that you should read!), the authors are frank that their idea about what a species is is purely instrumental. That is, what are their end goals, and what does the species concept get us? The biological species concept, which for many is the species concept, is optimal for mammals. But less relevant to most of the tree of life, and even within mammals it’s not absolute, but just a rule-of-thumb.

Bob Wayne is almost certainly right that the red wolf is a stabilized hybrid to a first approximation. He has the best genomes in the business of canids that I know of, and his 48,000 study was broadly persuasive in any case. The major issue isn’t scientific, it’s political. The federal government needs a clear and distinct set of criteria for the Endangered Species Act, but species are not really a clear and distinct concept.

Ultimately the question has to be what’s the point? That’s really how biologists figure out what species concept to use. To put my cards on the table it strikes me that a more honest and useful end goal is to focus on an ecological species concept. That way government bureaucrats wouldn’t be reduced to arguments about “genetic purity.” And I say this as a geneticist!

The question of Italy population genetic structure comes up rather often for various reasons. I haven’t visited this topic in much detail since reading Consanguinity, Inbreeding, and Genetic Drift in Italy, a very old book using classical genetic techniques. L. L. Cavalli-Sforza did not find much structure in Italy at the time, but it turns out that there wasn’t enough power in the methods. I have some access to Italian data sets and I can tell you that there is a lot of variation. Sicilians in particular are mixed in ways unique outside of the Iberian peninsula A few years ago using the PopRes data set Peter Ralph and Graham Coop found in The Geography of Recent Genetic Ancestry across Europe some interesting facts about Italy:

In addition to the very few genetic common ancestors that Italians share both with each other and with other Europeans, we have seen significant modern substructure within Italy (i.e., Figure 2) that predates most of this common ancestry, and estimate that most of the common ancestry shared between Italy and other populations is older than about 2,300 years (Figure S16). Also recall that most populations show no substructure with regards to the number of blocks shared with Italians, implying that the common ancestors other populations share with Italy predate divisions within these other populations. This suggests significant old substructure and large population sizes within Italy, strong enough that different groups within Italy share as little recent common ancestry as other distinct, modern-day countries, substructure that was not homogenized during the migration period. These patterns could also reflect in part geographic isolation within Italy as well as a long history of settlement of Italy from diverse sources.

There were limitations in terms of how much geographic specificity the PopRes data set provided them, so there was only so much you could say. One hypothesis could be that unlike much of Europe deep local structure within the Italian peninsula predating the Roman Empire persists to this day. The Latinization of Italy then during the late Republican and early Imperial period could be thought of primarily as a matter of cultural diffusion and elite emulation. This stands to reason in part because much of the Italian peninsula was inhabited by peoples who were already speaking languages very close to Latin. But, another possibility is that this deep structure exists became of more recent migrations. For example, the existence of Magna Graecia in southern Italy and Sicily was due to the migration of males from Greece in the centuries before the rise of Rome. The genetic distance of this population would be inflated due to this gene flow, and if Italian demographic history is such that gene flow across regions is low, then it would persist.

But things have changed since 2013. We know a fair amount more about European genetic history, thanks to ancient DNA. Just read Ancient human genomes suggest three ancestral populations to get a flavor. In short, it turns out that most European populations can be modeled as a three-way admixture, between one group with ancient Middle Eastern affinities, but different from modern Middle Easterners. Modern Sardinians are very close to this group. A second group are the indigenous European hunter-gatherers, who presumably expanded after the retreat of the tundra and had deeper roots in the continent, possibly at least back to the Gravettian period. Finally, a third group is a compound with a different Middle Eastern group, the European hunter-gatherer ancestry, and an ancient North Eurasian population more distant to other West Eurasians.

Most readers of this weblog are familiar with this song and dance. Now I want to submit new results from a paper in EJHG, The Italian genome reflects the history of Europe and the Mediterranean basin. A minor nit: I would assume that the Italian genome reflects the history of Europe and the Mediterranean basin! It would be really surprising if the Italian genome reflects the history of East Asia and the South China Sea!

What immediately jumped out for me about the results form this paper is that it seems clear that all non-Sardinian populations exhibit equal distance to Sardinians. That is, there is no “Sardinian-cline” in these data. Perhaps there are populations on the mainland that do exhibit a Sardinian-cline, but they haven’t been sampled in this study. What does this mean? The circumstantial evidence is strong that there was an intrusive population across Europe which arrived from the steppes spread across Northern Europe about ~4,500 years ago. The linguistic evidence tends to bind the Celtic and Italic branches of the Indo-European language family, so it seems the case that there was likely an intrusive population from Northern Europe that arrived sometime between 500 BC, when the Italian populations start to edge into history, and 2500 BC, when the Indo-Europeans swept Northern Europe. These people would presumably have amalgamated with the original Sardinian-like group. The best work suggests that though Sardinians have the most of this ancestry, it is still predominant in Southern Europe overall. It is curious then that the Sardinian fraction is so low, and, that it is relatively even. In fact, it is lowest in the southernmost Italian groups, and highest in Lombdary! Part of this is probably because Sardinian is not the same as Sardinian-like farmer. But I still would have expected some cline (I presume the Sardinians shifted toward the mainland are due to migration from the mainland). On the other hand, there is a large north-south gradient that you can see on the admixture plot .

The plot to the left is too small to make out well, but as people allude to Italian population structure in a world-wide context, this PCA does just that. The bright green are the Southern Italians, the bright light blue the Central Italians, and the red the Northern Italians. You see that the Southern Italians are shifted toward the Middle Eastern groups, while the Northern Italians are closer to groups like the Spanish and French. To the top right are Northern European groups, in purple, and the bottom right are Mozabites, with Turks in dark green in the middle, shifted toward Italians. Sardinians occupy the far left. As you can see, contrary to a commenter earlier this week, Italians of all stripes are not that distinct from other Europeans.

But, Southern Italians, and from what I have seen in private data Sicilians in particular, are distinct because of a possible admixture signal with exotic groups you don’t normally see in Europeans. If you look in the supplements the possibility becomes clearer. There is a lot of evidence that this admixture is North African. You see this in the ADMIXTURE plots in the supplements, as well as the IBD sharing patterns. The South Italian groups are enriched with the Mozabites and Moroccans, not groups from the eastern Mediterranean. The likely period when this admixture occurred is when Sicily was an Arab emirate, from 830 to 1070. More or less Sicily was then part of the greater Maghreb. Calabria also had a Muslim presence, though more tenuous.

Finally, the authors used LD patterns and reference populations to attempt to estimate admixture times:

We found evidence of the presence of a mix of Central-Northern European and Middle Eastern-North African ancestries in the Italian individuals (Supplementary Table S5). The estimated times of admixture ranged between ~2050 and 1300 years ago (y.a.), with an average of about 1650 y.a. – assuming 29 years per generation– for Northern Italians, and between ~3000 and 1450 y.a. (~2100 y.a. on average) for Central Italians. Finally, for the Southern Italian individuals, admixture between European and Northern African-Middle Eastern ancestry was estimated to have occurred about 1000 y.a. (see Supplementary Table S5 and Supplementary Results for a complete report of significant results).

The admixture in Southern Italy is estimated to have occurred ~1000 years ago. That’s pretty much what you’d expect. These methods tend to pick up the last signal of admixture, so there may have been ones earlier (e.g., Magna Graecia?). That might explain the relatively low fraction of “Sardinian” ancestry, as this area of Italy has had significant gene flow from outside Italy over the past 2,500 years, whether it be Greeks, people from other parts of the Mediterranean, and last Maghrebis.

The difference between Northern and Central Italians is intriguing. The reference populations are not optimal, and the dates have a wide interval. We actually know what was happening 2,100 years ago in Central Italy, and there was no admixture between Middle Eastern and Northern European groups. The Roman world empire was still in a nascent state. The Northern Italian admixture date might align with a German migration into Italy, or perhaps the Gauls in the centuries earlier. I really don’t know. I  am  of the inclination to suggest that the Central Italian signal might be somehow low balling the Indo-European admixture.

The authors say that their data will be released. But I looked up the accession number, and it’s not up there yet.

The banana is in the news again. You won’t be surprised about the topic if you read Dan Koeppel’s Banana: The Fate of the Fruit That Changed the World. As you may already know, the banana that we eat today was resistant the Panama disease which took out Gros Michel variety, which was the dominant one before 1960. I’m mildly hopefully that breeders will figure something out, technology is changing fast now. But, one interesting thing I learned is that artificial banana flavor, which most people are not impressed by, actually might resemble the Gros Michel pretty well. It’s just that two generations have come to think of the waxy and more astringent Cavendish as banana qua banana.

Saudi Arabia is a problem. They’re going to execute a Sri Lankan maid for adultery by stoning. The nation seems to have played in a role in radicalizin Tashfeen Malik. The vast majority of the 9/11 hijackers were Saudi. But here’s the question: what do we do with our ally? Invade and replace the monarchy with a democracy? Here’s a sad prediction: the outcome will be worse than what we’ve got now!

After 60 Years, B-52s Still Dominate U.S. Fleet. The article claims that some of them are going to be used until 2040! Attempts to replace them have failed. Why? Perhaps the B-52 is just a optimal design for the sort of missions it undertakes.

VW Destroys Myth of Efficient Germans.

Can Everyone Tell I’m Skinny-Fat?

In Utah Feud Over ‘Dirty’ Sodas, Flavored Darts Are Fired.

Over the past few years one of the major finds of ancient DNA is that human genetic patterns as a function of time often exhibit discontinuity. In plain language, the people who live in a given location are often unlikely to have descendants at that location 10,000 years down the line. This has resulted in an update to long held null and consensus models of of modern human dispersal across the world. To sum it up, that family of models tended to be predicated on a sequence of unidirectional migrations out of Africa in a step-wise fashion. This resulted in the stylized fact that genetic diversity decreased as a function of distance, with groups like Native Americans and Oceanians the most “steps” from Africans. Though all non-African populations are separated by the same number of generations from Africans, one result that would be implied and was seen in the data is that genetic distance from Africans of these populations was often higher than Eurasians, likely a function of their elevated drift (more drift means more divergence from ancestral shared allele frequencies). Once these regions were settled at a given time in the past genetic diversity so partitioned would slowly equilibrate through gene flow between adjacent demes.

Though this model captures some element of the truth, the reality of sharp local discontinuities in a given region is strongly indicative of the fact that there was no stable state achieved once the initial founders arrived. Geographical reality seems to dictate the sort of pattern of settlement outlined by the model of serial bottleneck Out-of-Africa model, but it seems likely that future population arrivals could be drawn from both closer to, and further out, from Africa. Second, it turns that most of the world’s populations are the product of relatively recent admixtures between very different ancestral lineages. Instead of overlaying a phylogenetic tree over a spatial landscape, one has to conceive of it as a reticulate network. This revised model is outlined in Joe Pickrell and David Reich’s Towards a new history and geography of human genes informed by ancient DNA. In place of diffusion and continuous genetic exchange between adjacent demes, the empirical data seems to point to a non-trivial proportion of “pulse admixtures.” That is, people who were very genetically different arrived, and mixed in with the local population, in a very short period. Sort of what happened in the New World with the arrival of Europeans.

But that’s all talk. A new paper in Molecular Biology & Evolution formally models these processes, Long distance dispersal shaped patterns of human genetic diversity in Eurasia (open access):

…However, it is likely that the Last Glacial Maximum (LGM) affected the demography and the range of many species, including our own. Moreover, long-distance dispersal (LDD) may have been an important component of human migrations, allowing fast colonization of new territories and preserving high levels of genetic diversity. Here, we use a high-quality microsatellite dataset genotyped in 22 populations to estimate the posterior probabilities of several scenarios for the settlement of the Old World by modern humans. We considered models ranging from a simple spatial expansion to others including LDD and a LGM-induced range contraction, as well as Neolithic demographic expansions. We find that scenarios with LDD are much better supported by data than models without LDD. Nevertheless, we show evidence that LDD events to empty habitats were strongly prevented during the settlement of Eurasia. This unexpected absence of LDD ahead of the colonization wave front could have been caused by an Allee effect, either due to intrinsic causes such as an inbreeding depression built during the expansion, or to extrinsic causes such as direct competition with archaic humans. Overall, our results suggest only a relatively limited effect of the LGM-contraction on current patterns of human diversity. This is in clear contrast with the major role of LDD migrations, which have potentially contributed to the intermingled genetic structure of Eurasian populations.

One of the things the authors found is that low population pairwise genetic distances across a wide range of human populations in Eurasia is probably due to LDD events homogenizing the landscape. Continuous gene flow between demes after the initial settlement Out-of-Africa would not have resulted in these patterns. Second, it seems reading the paper that the weak effect of the LGM population reductions on genetic diversity are partly a function of this mixing across long distances. Finally, it is notable in within Eurasia at least (they suggest that the Americans and Oceania may not fit this pattern) a sort of diffusion/wave of advance model does hold for the initial arrival of modern humans in Eurasia. They posit that this might be because archaic populations prevented long distance movements, or, that population fitness became too low when the bands were too small, the reference to the allee effect. Additionally, they also note that the evidence in Europe suggests both replacement with minimal admixture, and then later admixture with the local substrate.

But the details are less important than the big picture. The authors note that there are aspects of the data (dozens of microsatellites) that leave something to be desired, but this is a first pass. At the top of this post you see Peter Turchin’s Ultrasociety. Though the authors don’t get into much specificity in the discussion, I think the solution to what’s going on, and how LDD seems prevalent when you have a populated landscape, is that cultural complexity resulted in sharply increased returns to the victors in inter-group competition. Though some of the dynamics date back to the Pleistocene, the re-patterning of the world with “LDD”, what I call “leapfrogging”, is probably most salient for Eurasia during the Holocene. And, as the story about the Yakutian horses implies, this is also relevant to many domestic lineages.

How fast can evolution occur? More precisely, how fast can adaptation occur? The rough answer is pretty fast. For humans that’s clear when you read a book like 10,000 year explosion, or see the results from ancient DNA in papers, that selection (~1% coefficient) on variation can drive allele frequency changes rapidly (~0% to ~100%).

A new paper in PNAS on Yakutian horses is interesting because it highlights the power of selection and how quickly it can change populations when there’s enough genetic variation for adaptation to proceed. These horses are a stocky and hairy breed optimized for life in extreme cold, as Yakutia is in the heart of Siberia, as everyone who has played Risk knows. As a Palearctic species (with origins in North America!) horses have been present in this region since the last last Ice Age. So one model is that the Yakutian horses are a long present population adopted by the Yakut Turkic people, who arrived form the Altai in the last ~1,000 years. The alternative model is that they’re descended from populations brought by the Yakuts, and have undergone recent adaptation. Finally, there is a synthetic model which allows for admixture between the local and intrusive groups, so that adaptation can occur through introgression of alleles from the former to the latter.

To answer these questions they took a genomes from the extant population, as well as ancient or historical genomes. The TreeMix plot makes it pretty clear that the Yakutian horses are intrusive, and do not descend from the ancient populations, represented by Batagai. CGG101397 is from the 19th century, and you can see that is placed near modern individuals from the region, as you’d expect if they arrived with the Yakuts. Interesting, the Batagai individual is even further out that the Mongolian wild horse, which itself is rather diverged from the domestic population, which is not derived from it. They tested for non-trivial admixture between the Batagai lineage and the modern Yakutian horses, and did not find any evidence. This tilts the playing field toward the idea that Yakutian adapatations occurred from their own variation. Mind you, I don’t think they’ve totally eliminated the population of introgression with their sample sizes, as you can have alleles move between populations even if there is almost not detectable admixture.

But there are other elements which suggest that ancient variation wasn’t used. They note that selected variants seem to often be cis-regulatory elements, and not nonsynonymous ones. The former alter gene expression, while the latter presumably impact the function of the proteins, as they’re ultimately transcribed and translated from genes. There is a long argument in the geneticists community around this topic, and Sean B. Carroll’s book from the 2000s, Endless Forms Most Beautiful makes the case for cis-regulatory elements. Here’s a paper from Hopi Hoekstra and Jerry Coyne taking the other side. The authors argue that because the population didn’t have enough standing genetic variation there was a focus on these noncoding elements, which can alter regulation in a quantitative fashion.

The list of genes are what you’d expect when it comes to climate adaptation in this region. What is interesting, and noted in the abstract, is that mammoth and human also seem to have used the same mechanisms and pathways. What this implies is that there are certain genetic constraints, or at least low hanging adaptive fruit, at the level of the mammalian taxonomic rank. I’d go further judging by what we know of pigmentation. Basically, genetic variation is not endlessly pliable and infinite. The wheel is always reinvented, but from the same parts that have long been handy.

I was talking to a friend recently about life and its aims and meaning. Offhand I mentioned I was reading Meditations, by Marcus Aurelius, arguably the most powerful man in the world when he was composing it. There is debate about whether he wrote Meditations for public consumption, but that is somewhat irrelevant to why we moderns read it.

I could attempt to derive the fundamental theorem of calculus and reconstruct vast swathes of modern mathematics from first principles. But I don’t. Part of it is that I don’t have the skill or time. But another aspect is that I can stand on the shoulders of those who have come before, and lean upon the hard work that has come before. And so with natural science, which has a institutional backdrop I can’t recapitulate. There’s no point in reinventing the wheel.

There are those, like Steven Pinker, who suggest that the nature of modern philosophy is that it has been relegated to answering questions which seem well night insoluble. And I am in broad sympathy with this perspective. But the reason I look to the ancients is that often I find their musings more human and real than those of the philosophers of today, who in the analytic tradition put passion in thrall to reason, and on the Continent place a premium on stylistic verve at the cost of coherency. I don’t think that Marcus Aurelius, or Seneca or Christ for that matter, had any specific deep insight into the general human condition. But they probably addressed most of the same questions that the average person today has. There may be benefit then in seeing what their answers to the deep questions were, because presumably the generations that have intervened have selected at least some for memetic clarity, if it not depth.

The guy who runs the Pop vs. Soda page has really improved it. You can look at county level metrics just by hovering over the county. You can see counts, to get a good sense of the confidence in the representation of the underlying demographics. One thing that must be amended is that it’s not just soda vs. pop, there’s also coke in the South.

It is now very clear from these maps that there is an extremely sharp cline between the Middle Atlantic/New England region and the Great Lakes/Midwest on this dialect difference. I grew up in a soda region of upstate, though in the upper Hudson valley (95% soda), closer to New England than Syracuse. But in west-central New York you have counties right next to each other which are 60% vs. 15% pop, with reasonable sample sizes. Pennsylvania is similar. Clearfield county is 83% pop. Centre county just to the east is 19% pop (I know Centre county has Penn State, but the other counties around it are mostly soda as well).

In some places state lines matter a lot. Look at Oregon vs. California. The two “soda counties” in Oregon are more tied to the far north of California than the Willamette valley (the state of Jefferson). The Wisconsin-Illinois state line is a huge barrier as you approach Lake Michigan. But in other areas borders don’t matter so much. South Florida is part of soda territory, but that makes sense with its cultural history (lots of Jews with family roots in the Northeast). And there’s the huge zone that radiates out of St. Louis.

But in some ways the distribution of coke is the most interesting. First, state lines matter a lot in some areas. In the west there is a sharp drop off as one moves into Oklahoma, but an even sharper one into Kansas. Basically it’s the old Confederacy states, as Missouri has very little coke. As you move east it becomes more complicated. Northern Florida is part of the south, but you see in parts of Indiana that coke is a very common term for soft drinks. Why? It’s the “butternut” folk; descendants of Southerners who had settled large swaths of the Old Northwest. They retain connections and affinities with the South to this day.

Finally, on the Atlantic coast, you see the impact I suspect of border position and Northeastern migration into Virginia and North Carolina. The far west of North Carolina is like eastern Tennessee. West Virgina has an Appalachian extension in eastern Kentucky. State borders are less important in the east, just as is in the case further north. Cultural patterns that emerged organically when states were rather inchoate exist today in these regions, while newer states to the west were defined partly by their borders in terms of their cultural background (e.g., Kansas as a free state would be less appealing to Southern settlers culturally than if it was a slave state).

Those will more local knowledge can probably say more.

I recently watched the above video of a Demi Lovato song. I like Michelle Rodriguez’s stomach as much as the next guy (OK, perhaps more), but one thing that struck me in particular is that throughout the whole narrative arc Lovato, a 5’3 tall female, beats the crap out of many much larger men. Obviously this is a stylized fantasy, and the trope of “butt-kicking babes” is pretty well established in our culture now that we can slot it into the appropriate schema (Lara Croft?). But, recently I’ve been made aware of the magnitude of the strength differences between men and women, so these sorts of scenes are even more fantastical than were before. It’s almost as strange to me as an episode of Sailor Moon. It starts to violate the need for a “minimally counter-intuitive” scenario which is the criterion for a good realistic fantasy (yeah, that’s an oxymoron!).

The table to the left is from Costs and benefits of fat-free muscle mass in men: relationship to mating success, dietary requirements, and native immunity. I’m not too interested in the evolutionary psychological details at the heart of the paper. Rather, let’s focus on some statistics which are given. The key is to focus on the d column, this is the effect size, which indicates the differences between the means of the two distributions in standard deviation units. The mean ages of the two distributions were the same, 33. So d is naturally 0 for this measure. For height men are 1.75 standard deviations taller, on average, than women. This seems about right. You can see in body fat percentage that women have higher values than men. The d here is negative. It gets interesting once you get to muscles. These are measuring volumes. When it comes to arm muscles the average male has 2.5 standard deviation units more than the average female! I was also surprised by the thigh muscle, as arm musculature differences have always been more salient. Finally, there’s the fat free mass.

Some have pointed out to me before that the standard sexual dimorphism calculation in relation to humans may not be informative in the way we might think. There’s about a 10% size differences between men and women. But as you see in the “fat free mass” row the size difference is much more extreme if you account for the higher body fat of women. This is relevant because fat does not make you strong, it just adds more weight and volume. In terms of upper body muscle mass there’s less than a 10% overlap between the two distributions. The vast majority of men have more muscle mass than all women. 99.9% of females have less upper body muscle mass than the average male. The 61% greater average muscle mass in male upper bodies translates into 90% greater average strength (the respective values for the lower body are 50% and 61%). The authors of the paper note that “The sex difference in upper-body muscle mass in humans is similar in magnitude to the sex difference in lean body mass in gorillas, the most sexually dimorphic primate.” Obviously humans don’t engage in obligate harem building, and males are not totally devoted to agonistic behavior as their raison d’etre. So one should be cautious about extending the analogy too far. But this result will likely surprise many. It surprised me.

I spent a lot of time fixating on numbers above because I don’t beat women. More pointedly, I’ve never hit a woman. That’s not because of the way I was raised by my parents. Though they don’t countenance beating women, they came as adults to this country from Bangladesh, so their attitudes toward violence are more “liberal” in a literal sense than the average America. The culture in which I grew up though affected me more in regards to proper behavior in this dimension (the United States, and more particularly, middle class mores). I have a cousin who was beaten up by her husband several times (for the record, they both grew up in Bangladesh into their adulthood). She’s about 4’10 and he’s 5’8. Though I abhorred this behavior I didn’t have any concrete understanding of what this might have meant. I’ve gotten into fights, but only with guys, and they weren’t ever that much smaller than me. Now I understand better why a 5’8 man should never get violent with a 4’10 woman. The discrepancy is far greater than height would suggest, because the woman has less muscle mass per pound. I have some intuition about this because my wife is about my height and of athletic disposition for a woman, and when she tried to throw down my sorry out of shape ass it was pretty easy for me to prevent her. How is it possible that despite us being the same height, and her being in shape and me not being in shape*, I could still best her? Because I still had more upper body muscle mass due to being a male.

Now, mind you, there are a small minority of women who are stronger than a small minority of men. The statistics above make it clear. But it is very unlikely that in a pairwise interaction the very strongest females will randomly face the very weakest males. In terms of relationships, where domestic violence occurs, it is very unlikely for reasons of assortative mating that the very strongest females will be paired up with the very weakest of males. On the contrary.

There are two reasons I’m posting this. First, I’m assuming most of my male readers have never beaten a woman, so they too lack good intuition about what they might be capable of if they did do such a thing. There isn’t the sort of thing you really want first-person experience of, so scientific research which can gain you some sense of the shape of reality is useful. Second, the general skepticism and rejectionism of biological differences in behavior between the sexes which is now common on the cultural Left can start to bleed into other domains in the most surreal ways. I’ve had friends with science backgrounds who balk somewhat when I attempt to start any discussion about sex differences with the contention that there is a difference in upper body strength. They don’t necessarily even want to concede this without dispute. In these earlier conversations I didn’t know of any research on the magnitude of the difference, it just seemed “common sense.” But perhaps the positive diminution of domestic violence in some sectors of American society has had the side effect that people forget how strong the magnitude of difference in strength is?

Related: Men Are Stronger Than Women (On Average). In which I report that the average German man has a grip strength more powerful than the majority of the woman’s Olympic level fencing team.

* This was in the past, now that I lift my upper body muscle mass has increased considerably.