Why Women Need Fat

[kyrasdad]

Why Women Need Fat (http://www.salon.com/2011/12/19/why_women_need_fat/)

On any given day, more than half of women in the U.S. are on a diet. In hopes of slimming their figures, millions take on Atkins, South Beach, Lean for Life or Hollywood 48. Some never eat after 5 p.m.; others only eat Subway sandwiches. While the diet industry has a less than noble reputation, it’s clear that American women, far more than men, remain obsessed with dieting. But what can evolutionary biology tell us about gender difference and eating habits?

In a new book called “Why Women Need Fat,” Steven J.C. Gaulin, an evolutionary biologist, and William D. Lassek, a retired doctor of public health at the University of Pittsburgh, explain the science behind women’s unique relationship to their diet. In the book, Lassek and Gaulin make a surprising argument for a more positive outlook on fat and illustrate the differences between the ways women and men gain weight. Think of it as the evolutionary biology diet.

Salon spoke over the phone with Gaulin, who explained why one common ingredient in much of our food is making us fatter, why women are very different from men when it comes to weight and health, and how it really pays to think like an evolutionary biologist.

You and William Lassek co-authored the book. It’s surprising that two men would co-author a book on women’s health. How did each of you come to focus your research on this topic?

When I was teaching at the University of Pittsburgh, they had a policy that if you were over 55 and you weren’t trying to accumulate credits for a degree, you could take any course you wanted. Will, who was retired, showed up in my introductory level course, Sex and Evolution. From the first day he started asking questions that were so far over the heads of the students. So I told him to come to my office hours instead of confusing all of my students with a Ph.D.-level dialogue. Something we began to discuss was this finding that men have a preference for women with a small waist and larger hips. No one had really explained why men should have such a strong preference for this shape, and it’s not immediately interpretable in terms of comparisons with our close relatives. For example female chimpanzees don’t have that shape and male chimpanzees don’t seem to care anything about female shape when they mate. So it was a bit of a puzzle. That was the question that got us started and eventually led us to work related to women’s body type and weight.

In the first chapter of the book, you talk about the “polyunsaturated explosion,” during the 1950s that led Americans to eat much differently than they had in the past. What changed and why did it happen?

I don’t know if I normally subscribe to the principle that history is driven by the actions of a few influential people, but in this particular case there were two people who did exert a very big influence on our national diet. One was coming from an economic perspective and the other was coming from (what he believed) was a nutritional perspective. After Dwight Eisenhower had a major heart attack, when the American public became much more focused on heart health and nutrition, a popular nutritionist by the name of Ansel Keys made a lot of impact. He was committed to the notion that saturated fat was the culprit in the heart disease epidemic in the U.S. He advised Americans to replace saturated fat with polyunsaturated fats, in particular corn and soybean oils. Meanwhile Earl Butz, Nixon’s secretary of agriculture, had been tasked to get food prices lower. He decided to heavily subsidize and commoditize corn and soybeans in order to make them really cheap. So corn and soybeans became the basis of our entire food production system. And it continues today. The amount of these oils in the American diet increases significantly every year.

And you point out in the book that corn and soybean oil are high in a compound called omega-6, which is detrimental to health, especially for women. What is omega-6 and why does it make people fatter?

Omega-6 is a category of fat. It is technically a fatty acid. Omega-6s are one category of polyunsaturated fats found in seeds and grains. Now, it’s not bad to eat grains, it’s not bad to eat corn, and it’s not bad to eat soybeans. What is bad is that food processors extract and concentrate these oils from plants. In an ear of corn there isn’t that much corn oil, but when you subject it to industrial processing and extract everything but the oil, now you’ve got a lot of omega-6. It’s this heavy industrial processing of seed crops that makes our diet so unnatural. Omega-6s make us fat in a variety of ways. They promote fat storage. Omega-6 is also the precursor for certain signaling molecules called endocannabinoids. Will likes to call them the body’s home-grown version of marijuana. Endocannabinoids give you the munchies just like cannabis does. So the omega-6s are telling the body, “Store the fat you have.” And they are also telling the body, “Eat more, I’m hungry!”

But later in the book, you also give some reasons why gaining weight is quite natural in women. You provide an evolutionary answer to the question: Why do women gain weight after having children? It’s not the typical reasons that many women tend to assume — being too busy to exercise, eating poorly because of stress, etc.

Interestingly, human brain size plays a big role in why women need fat and why they tend to gain weight after having children. Humans have ridiculously big brains, which makes it more difficult to give birth to our infants. While chimps, orangutans and gorillas can literally sleep through a birth, human births, especially first births, are typically more than a day of very difficult labor. Women tend to weigh less before they have had their first baby because with a first infant, evolutionarily, it pays not to grow a baby that is too large. They can get stuck in the birth canal. It’s not so much of a problem for us in 21st-century North America because most women have fairly ready access to cesarean section. But for 99.99 percent of human evolution, it was a really big problem. The result of natural selection is that women tend to be lighter before they have a child because they need their first infant to be smaller in order to survive childbirth. Each infant that a woman has remodels the pelvis so that each subsequent infant can grow somewhat bigger. There is a positive correlation between birth order and birth weight. So the way to grow a bigger infant is for the mother to have more fat on her body.

American culture tends to vilify fat and fat people. You mention a particular instance in 2004 when the director of the Centers for Disease Control and Prevention appeared on national television claiming that obesity was approaching the No. 1 preventable cause of death. You think this crusade was misguided. Why?

Many M.D.s have bought this fallacious line that the optimal weight for women in terms of their health is what M.D.s call normal weight, a BMI between 18.5 and 25. And they have thought this to be true because women with higher BMIs exhibit a series of physiological measures that are indeed risk factors for disease in men. But they are not systematically risk factors for disease in women. If you actually look at the data from the National Health and Nutrition Examination Survey and data from studies done in other countries, the optimal weight for women who have had a kid is what doctors currently call “overweight.” I’m not saying that obesity is optimal, but all the findings show that overweight women survive better than normal weight women. We walk a fine line in the book because we argue that being overweight is not nearly as bad as your doctor has been telling you, but on the other hand, Americans are heavier than they need to be. There are diseases that still correlate with heavier weights, like diabetes. But if we ate a more natural diet, by that I simply mean the diet that we evolved to eat, we would all weigh less.

And we all seem to have a “set point” for weight. We have biological constraints that keep us from veering too far from our genetically determined “set weight.”

Yes, there are studies where they starve people and there are studies where they feed people huge amounts of food to see if they can fatten them up. In both kinds of cases, the body seems to have a lot of inertia in this regard. It does not want to lose weight and it does not want to gain weight regardless of where the person happens to fall on the BMI curve before the experiment. If you are starving the body, the metabolic rate slows down, the activity level goes down, a variety of mechanisms kick in to try to hold on to the weight that the body has. Likewise if we feed people twice as many calories as they normally eat, many are quite resistant to gaining weight. When we feed them three times as many calories, they finally gain weight, but the weight goes right away when they return to their normal calorie intake. The body knows where it wants to be. It’s interesting in that people differ greatly in what their set points are, but everyone seems to have a set point.

So what kinds of implications does this have for women who diet? Why do diets seem to fail women again and again?

One thing that’s important for women to understand is that your set point can change. That’s what “yo-yo dieting” does. When humans were hunter-gatherers, they never could count on where their next meal was coming from. They didn’t have grocery stores or refrigerators. In cases of bad luck foraging for food, the only thing they had for backup was stored body fat. There is an optimal amount of fat to store, which depends on how frequent and how severe your food shortages are. That is the point; a diet tells your body that there is a food shortage. Your body doesn’t know that you’ve decided to lose weight. Instead, the body takes a diet and goes, “Oh damn, I live in a food insecure world. The next time I get some food I better up my set point so that I have more fat for next time!” It’s so natural and obvious isn’t it?

It’s kind of bitterly ironic when you think about the history and intensity of the relationship between women and dieting in this country.

And it’s quite obvious once you start thinking like an evolutionist. But since barely half of the people in this country believe in evolution, a lot aren’t in a good position to think like one. Evolutionary biology isn’t just crazy theories about fossils from humans that are long gone, this is stuff that is highly relevant to decisions we make everyday in our lives.

In the book, you emphasize that instead of dieting to lose weight, women can change the way they eat in order to return to what you call a “more natural weight.” How do we determine what our natural weight might be and how do we get closer to it?

I think the best way to do that is just start eating the kind of diet that drastically reduces the amount of polyunsaturated omega-6s in the diet. The best way to do that is to stop eating processed food and to avoid commercially fried foods because they are always fried in these omega-6 fats. Potato and corn chips, for example, are a huge contributor of omega-6s in the diet. There is more than a gram of omega-6 in every single potato chip that a person eats. So that’s my solution. Many studies in the U.S. and other countries show that the single best predictor of how much a woman will weigh is how much omega-6 is in her diet.

Reading the book, I couldn’t help but consider how regional and socioeconomic factors might take influence over the different ways that women tend to eat. In the book, you advise women to eat wild (not farmed) fish, grass fed meat, as well as a diversity of organic fruits and vegetables. But is it possible for all women in the U.S. have access to this diet?

I’m a big advocate of family farms. I don’t think there’s any reason why we can’t have family farms in virtually any part of the country. Because the U.S. has commoditized corn and soybeans, there’s been a progressive consolidation of farms into big industrial agribusinesses. But family farms, that raise animals on the land, are a really good alternative. And when animals are grass-fed it changes the fatty acid profile of their meat — how much omega-6 and how much omega-3 is in it, which makes it healthier meat to consume. I don’t think that grass-fed or free-range is an elitist kind of food, I think it’s the natural, normal kind of food that we could have anywhere if we patronized our local farmers.

[WereBear]

This article has so much true stuff in it my head is spinning!

[Elizellen]

Gosh - what a read!! :thup:

Thanks for posting it, KD!

[M Levac]

I agree, mostly, except for this:
So what kinds of implications does this have for women who diet? Why do diets seem to fail women again and again?

One thing that’s important for women to understand is that your set point can change. That’s what “yo-yo dieting” does. When humans were hunter-gatherers, they never could count on where their next meal was coming from. They didn’t have grocery stores or refrigerators. In cases of bad luck foraging for food, the only thing they had for backup was stored body fat. There is an optimal amount of fat to store, which depends on how frequent and how severe your food shortages are. That is the point; a diet tells your body that there is a food shortage. Your body doesn’t know that you’ve decided to lose weight. Instead, the body takes a diet and goes, “Oh damn, I live in a food insecure world. The next time I get some food I better up my set point so that I have more fat for next time!” It’s so natural and obvious isn’t it?
What we have here is an intuitive explanation, not a reasonable explanation. It makes sense because that's how we'd design the body. But that's not how nature designed our body. We are not the product of intuitive design, we are the product of natural selection. Yo-yo dieting applies to all species that hibernate. They don't grow fatter as they grow older. They do get more efficient at using the same amount of stored fat for a longer winter, however, or at storing the same amount of fat from less food in summer. If that's how it works for species that hibernate, why should it work differently for species that don't hibernate? No reason. It works exactly the same way for all species, because the selective pressures that come from a potential disorder of an otherwise normal yo-yo dieting has long been sieved out of us through natural selection. I understand I'm not making a specific point about yo-yo dieting, but rather explaining the general idea of natural selection, and how it applies just as much to yo-yo dieting as to any other trait or advantage for survival.

Here's a specific point. Growing fatter as we age is not an advantage for survival. On the contrary, growing fatter makes us slower, therefore any species who had a tendency to grow fatter as they aged would have soon be sieved out by predators. Those that remained lean - therefore quick - would have survived and reproduced. Predators don't care how old you are, they only care how slow you are. Furthermore, prey doesn't need to be faster than predators, they only need to be faster than other prey. This is how natural selection works.

On the other hand, why is there a correlation between birth weight and birth order? Apparently, this is why:
But later in the book, you also give some reasons why gaining weight is quite natural in women. You provide an evolutionary answer to the question: Why do women gain weight after having children? It’s not the typical reasons that many women tend to assume — being too busy to exercise, eating poorly because of stress, etc.

Interestingly, human brain size plays a big role in why women need fat and why they tend to gain weight after having children. Humans have ridiculously big brains, which makes it more difficult to give birth to our infants. While chimps, orangutans and gorillas can literally sleep through a birth, human births, especially first births, are typically more than a day of very difficult labor. Women tend to weigh less before they have had their first baby because with a first infant, evolutionarily, it pays not to grow a baby that is too large. They can get stuck in the birth canal. It’s not so much of a problem for us in 21st-century North America because most women have fairly ready access to cesarean section. But for 99.99 percent of human evolution, it was a really big problem. The result of natural selection is that women tend to be lighter before they have a child because they need their first infant to be smaller in order to survive childbirth. Each infant that a woman has remodels the pelvis so that each subsequent infant can grow somewhat bigger. There is a positive correlation between birth order and birth weight. So the way to grow a bigger infant is for the mother to have more fat on her body.
Here's the big problem with this idea. Why do we still have to use cesarean even with obese women? I'm not talking about choosing, I'm talking about having no choice, or the kid and/or mother dies. The problem is with the hormones and enzymes that regulate the body's changes during pregnancy. It could be about o6 fats that somehow interfere with these hormones and enzymes, dunno. But the point is there is a disorder. Otherwise, no cesarean necessary. I mean, that's a modern procedure that our ancestors would not have had access to, therefore we are the product of those who could give birth easily without resorting to c-section.

Here's how the small waist/wide hips come into play. Wider hips mean easier birth, therefore men prefer women who can give birth more easily. That's all there is to it. But how does it work? Easy. The men who preferred narrower hips ultimately saw their women and/or kid die in childbirth. The genes that dictate this particular preference died off.

Opposite this is the grow-fatter-as-we-grow-older negative selective pressure. So, how do the two opposite advantage for survival work? Easy. The same hormones and enzymes that regulate the body's changes during pregnancy also include a cutoff point for the maximum amount of fat and girth of the birth canal and hip width. This is done with the same mechanisms that regulate how many sets of teeth we grow, and how long and big our bones grow. It's all about genes and how they can be turned on and off by those hormones and enzymes. Incidentally, this is also why men do not prefer overly fat women. There seems to be a sweet spot of preference, I'm going to call it the pin-up girl ideal. Not too skinny for easy birth, not too fat for other reasons. Think about it. If those hormones that cause the birth canal to grow wider did not have some mechanism to prevent it from growing overly wide, we'd end up with women with hips 5 feet wide, just from the bone growth.

An interesting point about brain size. It's possible that the primary reason we grew shorter with smaller brains once we adopted agriculture 10k years ago is the effect of the product of agriculture on the hormones that regulate pregnancy. It prevented full growth of birth canal, therefore tended to cause problems at birth for bigger babies and/or smaller women, therefore those who did survive were invariably smaller and had smaller brains. But we were smart enough to figure out a way to fix this with the invention of the c-section. It didn't fix all the problems (like the root cause for example), but there you go.

Now here's an interesting implication of the above. We could hypothesize that a bigger brain has a higher potential for smarts, therefore we must have been smarter before we adopted agriculture. However, paradoxically, the problems associated with agriculture forced us to use our brains more than otherwise to find solutions for those new problems. When all is well, nobody works to find solutions. Yet another interesting implication is that we have developed a global culture of finding solutions to problems, but without addressing the root cause.

I should write a book about stuff.

[WereBear]

I should write a book about stuff.

Yes, you should!

[M Levac]

It just occurred to me that we have the ability to grow fatter very quickly, and grow leaner equally quickly. So, for the purpose of reproduction, it's entirely possible that women grow fatter very quickly, give birth, then grow leaner equally quickly. All of it a product of natural selection.

Consider Feltham's experiment. He grew 16lbs fatter in just 21 days, and he's a man. He did it with diet, but to paraphrase Taubes, this is only possible if the hormones that regulate fat tissue are there to be acted upon by diet. When women grow a kid, they produce tons of growth hormone for that purpose. Women, as opposed to men, are resistant to GH. However, it's possible to overcome this resistance with tons of GH. Now if there's tons of GH, there should be an effect on the body composition of women during pregnancy, but the bulk of the changes most likely occur at the fetus. This suggests pregnant women become even more GH resistant, probably also at the fat tissue. I'm not sure where I'm going with this, but I thought maybe insulin would be that much more active by comparison, likely as a means to compensate for the flux of GH, but not necessarily by increasing insulin per se. Think of it as hormone partitioning, much like fuel partitioning. GH is directed mostly at the fetus, while insulin is directed everywhere else. Soon after birth, GH and insulin return to normal. This makes a bit of sense, as now fat tissue is more sensitive to GH, and more resistant to insulin, releasing more fat than during pregnancy, thereby providing more fuel for the baby. It all works out. It's an idea.

[WereBear]

I will admit the fellow got into the weeds with the whole pregnancy thing. My own understanding is that growing a baby is an incredible strain on the body; and doing it on the SAD is asking for thyroid and pancreatic strain, isn't it?

Things can just snowball from there.

[Ilikemice]

He is very, very good at explaining things. Interesting read.

[Whofan]

Loved this article. I'm buying the book. But a massive shift in public perception, or government intervention, is needed to increase the number of family farms so that everyone has access and can afford to buy from them. That's the only way those farmers can hold out against the big corporations. I just don't see it happening any time soon, and maybe it never will. Thus the poorest people (and the wealthier but misinformed) will continue to eat from MacDonalds, 99cent stores, 7/11s, and have grains/sugars/cheap oils in their supermarket baskets. The whole thing is mind-bogglingly unfair and self-destructive.

[leemack]

Do only half the people in the U.S. believe in evolution? If that's true......wow!

Just checked and apparently only about half of people in UK believe in evolution - though in our case it's more to do with poor education than religious belief.

[teaser]

Martin Levac said; Here's a specific point. Growing fatter as we age is not an advantage for survival. On the contrary, growing fatter makes us slower, therefore any species who had a tendency to grow fatter as they aged would have soon be sieved out by predators. Those that remained lean - therefore quick - would have survived and reproduced. Predators don't care how old you are, they only care how slow you are. Furthermore, prey doesn't need to be faster than predators, they only need to be faster than other prey. This is how natural selection works.

I'd throw in that as a species, we're so kickass, we can afford to have some members of the tribe be a little fatter and slower in exchange for their wisdom. My grandmother was fat. I don't remember her spending much time being chased by wolves and bears.

The fattening of postmenopausal women has a lot to do with the hormonal changes that preclude pregnancy--and not being able to get pregnant past a certain age can mean Grandma has a longer lifespan, which can increase her kid's and grandkid's chance of survival. The stuff about nature only wanting us around long enough to procreate just isn't true for humans.

[WereBear]

Do only half the people in the U.S. believe in evolution? If that's true......wow!

Just checked and apparently only about half of people in UK believe in evolution - though in our case it's more to do with poor education than religious belief.

In our case, it's both. Certain Protestant religious have been herded towards home-schooling, from highly dubious sources that make money for the churches, and these are not quality educations.

It's been a freaky trend since the school were desegregated. Fine behavior from people who supposedly follow Jesus!

[M Levac]

(replying to Teaser)

As soon as civilization starts (10k years ago or so), the big picture changes, but our genes are still fully adapted to a non-civilized environment. So now we have non-civilized genes opposing civilized environment as selective pressures. 10k years is not enough to have a significant impact on our genetic profile, but it is more than enough to have an effect from an environmental point of view (think epigenetics, which only takes a few generations to manifest itself, and then promptly eliminate the unadapted). So our genes are the same today, and the physiological differences are mostly due to environment. Return to a previous adequate environment, and our genes now return us to a state of 10k years ago.

I agree that as a species, we kick ass, and this means we can take care of individuals who would otherwise not make it without group dynamics. However, it does not imply that those same individuals are as healthy as they could be, if there was no group dynamics to compensate for their individual weakness. In other words, group dynamics allow otherwise unadapted individuals to reproduce. We see this with modern medicine. Instead of natural selection, we now have artificial selection.

We could probably argue that as a species, our evolution has been influenced by group dynamics ever since we grew a bigger brain, as the bigger brain allowed group dynamics to manifest themselves. But then we could also argue that we took advantage of group dynamics - without agriculture - for the bulk of our evolution (2M years), which means any evolutionary inference based on the last 10k years is most likely false. Now I don't know what we looked like before 10k years, but we most likely didn't look like we did once we adopted agriculture. As we know, the primary cause of obesity is a high-carb diet, therefore a product of agriculture, therefore if indeed women need to be a bit fatter for the purpose of reproduction, they certainly don't need to be as fat as they could be on a high-carb diet, nor can we imply that being fatter due to agriculture is ideal for women.

As a rule, women have 50% more fat tissue than men. So when we say women need to be fatter, we have to ask - fatter than what? Women are already fatter then men. Should they be fatter still? No, not if this extra fatness requires agriculture.

[M Levac]

I checked Price's Nutrition and Physical Degeneration again. I don't see overly fat women anywhere. I mean, maybe they do grow a bit fatter the more kids they have, but certainly not as fat as they could with a non-traditional high-carb diet.

[teaser]

I wasn't really disagreeing with your basic point--that the level of fatness we get to today is pathology, rather than a useful adaptation. Some of the studies from the sixties, where obese people went on total fasts for over a year is illustrative of this--there's unlikely to have been many periods where anybody needed to carry enough body fat to go more than a year without eating.

With the woman/man thing--a man can still procreate at sub-ten percent body fat.

Each infant that a woman has remodels the pelvis so that each subsequent infant can grow somewhat bigger. There is a positive correlation between birth order and birth weight. So the way to grow a bigger infant is for the mother to have more fat on her body.


This part of the article--I think it's as likely that each pregnancy is a challenge to the mother's system--especially on the modern diet. Challenge brain cells with more work than they expected--the part of the brain exercised will actually grow. The part of a London cab driver's brain that deals with navigating the city is larger during their working life than average, and shrinks down in retirement, when they use it less. Muscles grow when challenged. Bone becomes thicker and stronger. Skin thickens with calluses. If fat didn't grow into the job it's given, that would make it the odd-man out.

I wish that worked with hair. :sigh:

[s-piper]

MLevac,

I'm sorry, but I cannot agree with your logic.

First of all, there's way more to natural selection than just running from predators!

It's been shown that in modern times a little extra weight (but not a lot) is actually associated with increased health as we age. The hypothesized explanation is that it makes us more resilient to the age related health issues that come up like the need for surgeries, cancer treatments, etc.
Well these modern diseases and treatments wouldn't have existed then, and if they did were rare...however, that does not mean illness had no influence on survival as a person aged.
I would think it had huge influence!
It's well established that children and older people tend to be most vulnerable to dying from communicable diseases (think influenza).
And in a time when there were basically no medicines what-so-ever having extra body fat could be an advantage because if you're too sick to eat and at the same time need extra energy to mount an immune response, you have stores to fuel that.
Not to mention you'd be sharing your body with, by today's standards, huge numbers of parasites. Fleas, ticks, lice, intestinal worms. All using you as a food source. Intestinal parasites, especially, can lead to nutritional absorption problems. So being better at storing nutrients when you get the chance to eat might make you more resilient to the effects of parasitic infection too.

In evolutionary biology there's also something they call the Grandmother Hypothesis.
It was originally developed as an explanation for why women go through menopause and can live for many years after doing so since both are relatively rare. In most other species females either continue to be fertile until death, or tend to lose fertility close to the end of their life.
The explanation is that it was more evolutionarily advantageous to for a female to stop having children herself at a certain age, and instead focus on helping the survival of her children and grandchildren (and in doing so the survival of her genes).
There may be something to that when it comes to age related weight gain. In a highly social species like humans it might have been advantageous to the species for calorie requirement to go down with age. For example children would need calories in order to grow, men in their prime to fuel muscle growth and stamina (and better assure survival by allowing them to be more successful at hunting, defending the tribe, etc.), and women in their prime to fuel pregnancy and breast feeding, which women at the time are thought to have been in an near constant state of (no birthcontrol!). So if a human can eat less as they get older and survive they may live longer and, possibly, during times of food scarcity, can give more to their children and grandchildren...thus better assuring the survival of their genes.

There's also the concept of relaxation of evolutionary pressure, and I can well see that happening when it comes to being able to run from predators.
So maybe it really isn't advantageous to gain weight with age, but it also isn't disadvantageous enough to be selected out in individuals who tend to.
To put it bluntly, if the slower, heavier people are older it really doesn't matter if they're less able to run from a predator and thus more likely to die...so long as they've already passed on their genes to fertile offspring their genes won't be selected out any more than the genes of people who stay lean into old age.

[Water]

And I must respectfully disagree with this:
>
>I’m a big advocate of family farms. I don’t think there’s any reason why we can’t have family farms in virtually any part of the country. >Because the U.S. has commoditized corn and soybeans, there’s been a progressive consolidation of farms into big industrial agribusinesses.
>
The commoditization of corn and soybeans may have contributed to the consolidation of farms but consolidation has happened in almost all areas of modern economies - autos, computers, coffeehouses, etc. We can't have family farms everywhere for the same reason we don't have family steel companies - the addition of capital and automation drives prices down and makes the small producer uneconomic except for niche markets. There are lots of great small farms. Should demand for grass fed organic beef really grow and prices appear attractive I'm sure that agribusiness will enter the grass fed beef market too.

[M Levac]

First of all, there's way more to natural selection than just running from predators!
Yes, exactly. There's more than just one selective pressure that determines our genetic profile. Take food scarcity for example. There's more than one way to counter that besides the ability to store more fat. The primary trait for survival of humans is smarts. This would more than make up for the inability to store fat during famine. In fact, it makes up for basically every other weakness we have. Species tend to specialize in one trait. We specialized in smarts. But unlike other species, our smarts isn't set at birth. We gotta learn everything we know, and this takes time. We do have one innate ability (i.e. genetic), and it's the ability to learn. I said it takes time, so the idea of menopause due to focusing on passing knowledge makes sense, since it gives more time to pass on knowledge simply because less time is devoted to pregnancy.

Another way to counter famine is food storage. Other species do this instinctively. Humans are smart, we do it too, only much better because of our smarts. The point is that we now have to figure out if smarts is opposed to grow-fatter-as-we-grow-older as selective pressures.

Between growing-fatter and being-smarter, which genetic line is most likely to survive during any situation that demands either trait to manifest? I'm going to say smarts has always been the primary trait for our survival.

About parasites. How can smarts counter that, better than growing-fatter could? Rather, what effect do parasites have on smarts, or on growing-fatter? If parasites cause us to get dumb, that's it for that genetic line, we're not the product of that genetic line obviously. If parasites cause us to grow fatter, we have to have smarts to compensate (or develop a physiological resistance or symbiosis)). And if we keep our smarts to compensate, we probably figured out a way to counter parasites, therefore a way to counter growing-fatter due to those parasites.

I mean, think about it. All of us on this forum used our smarts to figure out a way to compensate for the growing-fatter due to a high-carb diet. If that's how we do it now, then that's how we must have done it throughout our evolution, because I believe smarts has always been our primary trait for survival. Here's an interesting idea. Many of us here have experienced an improvement in cognitive function after going low-carb (myself included), all the while growing leaner in the process. This suggests a direct correlation between smarts and leanness. Seth Roberts' experiment come to mind. He looked at what foods make his brain work better, and those same foods are low-carb, i.e. butter/lard, those same foods make us and keep us leaner.

Now to put it all together to see if growing-fatter-as-we-grow-older is still valid. It takes time to pass on knowledge, we're smarter if we're also leaner, we get smarter the longer we live. When does growing-fatter ever become an advantage? Never. This leaves only one way where growing-fatter-as-we-grow-older is valid. Somehow the genes that regulate fat tissue get lazy, and that's the only reason we grow fatter as we grow older. The problem is that's not how genes work. Genes keep doing the same thing unless acted upon by external stimuli. So, what external stimuli would cause genes to make us fatter as we grow older, when all is well? By all is well, I mean we're smart enough to have ample food supply, to avoid parasites, accidents, obesogenic foods, and basically all things that would otherwise put pressures on the genes that make us fatter, and the genes that keep us smart.

Insulin-induced lipohypertrophy. That's fat tissue growth due to chronic hyperinsulinemia, either from injecting insulin, or from secreting lots of insulin. That's an external stimuli. The point here is that otherwise fat tissue remains small. If we believe growing-fatter-as-we-grow-older is valid, then we must invent a condition that I'm going to call unknown-induced lipohypertrophy. Unknown as in there is no known cause, but it happens anyway. As I've learned, there is always a cause, and the lack of a cause is not a cause of anything. Take exercise for example. We believe we grow fatter because we are not active enough, i.e. inactivity causes obesity, i.e. nothing causes obesity. Sorry, obesity doesn't just happen for no reason. So, genes don't get lazy.

Women grow fatter after menopause. They don't grow fatter for no reason, it's the hormones that now have a different profile, and cannot maintain pre-menopause leanness anymore. Like you said, most other species either remain fertile until death, or tend to lose fertility toward end of life. For those species, growing fatter after menopause doesn't really apply. But maybe it does. We could hypothesize that growing fatter after menopause is detrimental, therefore remaining fertile until death is how this is compensated for. (Bear in mind all other species do not rely on smarts, they rely on other mechanisms for survival.) But women do grow fatter after menopause, and continue to live a healthy long life long after menopause, so there must be something to compensate for the detrimental effect of growing fatter. This must manifest after menopause, or must already exist before menopause. I'm going to say it already exists before menopause, since women do have 50% more fat tissue than men, yet are equally healthy. In other species, females are also fatter than males (probably also for the purpose of reproduction), so this point about some protective mechanism for the extra fatness before menopause is all the more valid.

Homeostasis. When opposing pressures stay the same, the system stays the same. After menopause, women don't continue to grow fatter as they age. If they do, then there must be an extra stimuli on top of whatever happens to the hormones that regulate menopause and fat tissue. When menopause hits, the system changes as opposing pressures are now different and try to equalize, but once that's done, fat tissue should remain the same size onwards.

Finally, compared to what? The facts we know says leanness is the rule for humans. So whatever hypothesis we have about women needing to be fatter, shouldn't say women must be overly fat. The association between fat% and longevity must take into account that we intentionally semi-starve ourselves to remain lean. As we know, semi-starvation does not lead to good health, therefore to longevity. So, this association is skewed in favor of those who do not semi-starve themselves in spite of eating a high-carb diet. From this, we cannot conclude that being a little fatter is good for longevity.

It's really really hard for me to agree to the idea that growing fatter is advantageous (or at least not detrimental or even irrelevant) besides for women for the purpose of reproduction and mostly during pregnancy, and no more than absolutely necessary for that purpose.

[M Levac]

I thought of the idea that traits for survival could also become detrimental if taken to the extreme. Growing fatter is one such trait. It could become detrimental to survival if taken to the extreme. There is no such limit for smarts. So between the two, the trait most likely to survive is smarts, and the trait most likely to be eliminated is growing fatter. This would happen if the two traits are present in the same species, and they are opposing each other as I explained with this correlation between smarts and leanness.

[teaser]

Selecting for intelligence doesn't preclude selecting for other advantages.

[WereBear]

We are making the same mistake he did.

If anything is genetic, it's the way we react to an "industrialized" diet. Look at photos of our grandparents! Look at a typical crowd in the 1940's.

A circus fat man from 1900 would be one of the slimmer people out on the street today. That's not evolutionary science. That's eating in a way that stores fat.

[teaser]

We are making the same mistake he did.

If anything is genetic, it's the way we react to an "industrialized" diet. Look at photos of our grandparents! Look at a typical crowd in the 1940's.

A circus fat man from 1900 would be one of the slimmer people out on the street today. That's not evolutionary science. That's eating in a way that stores fat.


I don't disagree... except that some get hit harder by the modern diet, and some have a harder time recovering, even on a well-formulated low carb diet. The punishment doesn't always "fit the crime" (in fact generally doesn't) and a diet that doesn't make one person and their twin fat will make another person and their twin fat.

It doesn't have to be a matter of whether or not tendency to be very obese in an obesogenic environment is an advantage. But a tendency to carry an extra twenty pounds of fat--that could keep a person alive for an extra month, during a famine, while minimally affecting physical function during better-fed times. This slight, advantageous increase in ability to store body fat might be exaggerated when the person is exposed to modern foods.

[M Levac]

Well, I'd say most of us tend to grow fatter on high-carb, and most of us tend to grow leaner on low-carb. Health also follows those two, high-carb vs low-carb, it's obvious which one is best for health. Those who are protected from carbs/obesity aren't necessarily protected from the carbs/diseases that come to those who are not protected from obesity. So I'm going to say they probably suffer just as much, but maybe not necessarily from all the same conditions.

Does this apply to surplus fat as a survival advantage? I don't think so. As I said, there's an inherent limit to the usefulness of surplus fat, and if it's due to high-carb, there's also a correlation with smarts. Other species that grow fatter for some purpose, don't grow so fat to their detriment.

Group dynamics require more smarts than that required by any individual within the group, or outside the group. This puts even more pressure on maintaining those smarts, therefore on any inhibitors of smarts overall. Incidentally, one such inhibitor is the breakdown of group dynamics, since group dynamics allow smarts to be transmitted to others within the group. To put it differently, group dynamics require smarts, and the smarts required for group dynamics require group dynamics for those smarts to be maintained.

Teaser, I agree that intelligence does not preclude selecting for other advantages. However, it does if those other advantages preclude selecting for intelligence, which I believe is the dominant trait for our survival. In other words, our evolution was dictated by selecting for intelligence, therefore against any other trait that selected against intelligence.

But intelligence is not enough, we must also have the means to apply this intelligence physically. For instance, if we developed persistence hunting, then we must also have the means to do it, and this means remain lean, quick, agile, etc. If we followed the herd to hunt buffalo, we must also have the means to do it, and this means remain lean, strong, have greater endurance, etc. If instead we stayed in the same spot for thousands of years due to ample food supply to support a small group, this means we must be strong enough to carry a heavy load to our cave, and this means we must not already carry a heavy load as fat tissue, etc.

The way to see this is that any trait which prevented us from manifesting our intelligence physically (persistence hunt, following the herd, etc) was selected against with each generation. It doesn't matter how smart were were, if we were not able to apply this intelligence physically. Today, one of the smartest man on the planet can barely move a single finger, but due to group dynamics and modern applications of our intelligence made possible by others who are physically capable, we can still take full advantage of such great genius. The point is the abilities to apply our intelligence physically were invariably selected for side-by-side with intelligence. So, slow, weak, sick, fat, and dumb, all selected against simultaneously.

[Whofan]

A circus fat man from 1900 would be one of the slimmer people out on the street today. .

Off topic, I suppose, but it's a slow day at work so I googled that just out of interest. People considered so freakishly fat in the 1900s that they became circus exhibits certainly wouldn't be unique enough to get the job today. But they wouldn't be among the slimmer people we see on the street these days either.

However, that might depend on geography: I don't see many obese people in NYC but at the racetrack in Sarasota, NY I was stunned to see that practically EVERYBODY was overweight with bulging bellies and a huge percentage were morbidly so. The few thin people were men. The only elements that would make NYC different are (a) larger percentage of people in the pre-metabolic 20 and 30 age groups and (b) more people walk more often, because it's ultimately quicker to get around that way.

[s-piper]

MLevac,

Okay, I see what you're saying. I think we may be interpreting what the book is saying differently.
I never thought the authors were saying that women should be overly fat. Being overly fat is detrimental to health and survival in all environments. No argument there.

I actually kind of interpreted the title of the book to be about why women need fat as a macronutrient in their diet.
I don't know that for sure, but I ordered the book yesterday so I guess I'll find out when it arrives.

However, in thinking, it could mean something else too.
No one debates that women do need a higher body fat percentage than men.
When it comes to essential body fat, what's needed for health and reproductive functioning, for men it's 2-5% and for women it's 10-13%. So in that way women need fat.

Those are the two interpretations I can see.

I don't know of any relationship between fat storage and intelligence. From a scientific pov I wonder if any studies on that have been done (probably have). From a human pov I'm a bit insulted by that selecting for tendency to store fat would somehow select against intelligence because it plays directly into the old "you're fat because you're stupid" argument.
It would be interesting to see what's been done though. Maybe if I have some time (not likely!) I'll look through PubMed.

Anyway, I feel like we've gotten way off topic. Survival is based on many factors, and wether it's our modern environment or evolution selecting for fat storage genes in response to thousands of years of hard living, or, in my opinion, a combination of both, I suspect the authors of this book aren't really proposing anything all that radical...except maybe that women shouldn't be pushed toward a low-fat diet like CW says.

If there's still interest I'll post what their actual thesis is after I read the book.

[M Levac]

It's a delicate argument. I prefer to avoid it by making sure when I say "fat, stupid, weak, slow, etc", I put commas everywhere. Causality isn't established, unless we believe obesity is a moral failure. I don't. So I could very well state it like this "we're stupid because we're fat", or "we're stupid and fat because of some third common cause". Based on the many anecdotal reports of going low-carb, I prefer the last one. I could even say "we're stupid and fat for no common cause, it just happens to be that way". I've met lots of stupid lean folks, no reason they should be stupid, but there you go. From an evolutionary point of view however, we have to look at it as traits that can oppose each other, and which one dominates and which one inhibits the other(s). As a side note, I believe morality is a product of survival. We have developed inhibitions that promote our survival within group dynamics. Otherwise, such inhibitions are unnecessary.

For whether it's fat in the diet or fat tissue, I'm going to say it's both. But I thought the article was ambiguous on that point. The problem here is that when we eat more fat, therefore when we go low-carb, we get leaner. We also get healthier. So yes, more fat in the diet. But then this means if we also say women need to be a bit fatter, we don't mean fatter than they could be if they also ate more fat, i.e. low-carb. Unless the article assumes eating more fat equates to growing fatter, but that's a mistake.

[liddie01]

actually, more educated people tend to have less offspring, so I doubt that intelligence is being selected for anymore.

[s-piper]

Unless the article assumes eating more fat equates to growing fatter, but that's a mistake.

I don't know, maybe the author of this article was implying that. I really don't care to be honest.
People who are interested enough in this subject will read the book, and those who aren't but believe that eating more fat equates to growing fatter will continue to regardless of what the person who wrote this article was going for.

I do feel confident that no one, be it the authors of the book, the author of this article, nor teaser and I, is saying women need to be obese.
Do they need to be fatter than men? You could say yes because men can be healthy with a lower percent body fat, but women can still get pretty lean and be very healthy.
All I really got from the article is them saying that it's normal to gain weight after having children, which is true. Gaining 10-20 lbs after having a few kids is normal. Gaining 50-100 isn't though, and no one's saying it is.

[rightnow]

I thought of the idea that traits for survival could also become detrimental if taken to the extreme. Growing fatter is one such trait. It could become detrimental to survival if taken to the extreme. There is no such limit for smarts. So between the two, the trait most likely to survive is smarts, and the trait most likely to be eliminated is growing fatter. This would happen if the two traits are present in the same species, and they are opposing each other as I explained with this correlation between smarts and leanness.

That's hilarious! So either you are thin, or you are an idiot. :lol: Actually I would say that attempting to survive in an environment better adapted to thinness might lead to even more development of other capacities in fat people as compensation. I am referring here to ordinary fat people over evolutionary time, not pathologically fat people like the present day of course.

PJ

[teaser]

actually, more educated people tend to have less offspring, so I doubt that intelligence is being selected for anymore.


Only if we assume formal education tracks with intelligence. :lol:

[rightnow]

If there's still interest I'll post what their actual thesis is after I read the book.
Please do, I might like to read it.

My impression from the above was that they were saying women needed to ingest fats, not that women needed to BE fat. Being fatTER than men doesn't make a woman fat. Pathological fat is bad.

The more I read on nutrition the more I am agog at this basic fact:

Our body builds every single cell from what we eat. Every. Cell. Every bone cell, every lymph node and blood vessel and the lymph and blood itself. Every organ and every enzyme and hormone and more that are put out or generated by those organs. Every nerve sheath and every cell membrane, every brain neuron and every skin cell. EVERYTHING.

Now, think about what most people eat. The body is able to 'substitute' things it needs (choline, phospholipids) with things it HAS if it doesn't have what it needs (transfats, rancid seed fats, etc.). It's like a duct-tape solution in an industrial application -- it'll hold, sort of, but is never going to be good and will have to be constantly patched forever. Now the body not only needs what it needs today, but it needs what it should have got yesterday, and it also needs more to help it with the extra work of deconstructing its temporary duct-tape projects and expediting them outward and replacing them.

Everything we eat also comes with toxins, from plastics to heavy metals to stuff the human body never could have thought of. And all those have to be dealt with in ways that basically "cost resources" of various organs and substances and more.

The sheer quantity of cells, membranes, everything that the body has to create every day is utterly mind boggling. Really our brains can't even get around it and we're only "wildly guessing" anyway.

Most people probably do not eat enough basic "health raw materials" for the body to do what it needs on any given day. Let alone every day. Let alone if the person's body is oversized. Let alone if the person's body is unhealthy or challenged in any way (age is a form of challenge, due to the drop in hormonal output).

Given the issues with our farm industries from vegetables to meats, whatever we're getting from our food is only fractionally what it could or should be. Vastly less of the good building materials; vastly more of the lesser-sorts or actual toxins of many kinds.

Now consider that the primary 'construction materials' the body requires are:

Lipids
Amino Acids
Minerals
Vitamins

It probably isn't hurt by things which doesn't qualify as the above but are useful such as "other enzymes and substances" (not technically vitamins) found in fresh foods and some supplements. (ALCAR and Chlorella for example.)

(Carbohydrates are not a construction material although the energy they provide could contribute to the construction, if the liver and other systems weren't mostly busy expending more effort to deal with the carbs than they're usually worth, if ingested in quantity.)

The body-wide need for and positive response to lecithin and choline are profound for example.
http://hypernutrient.blogspot.com/2013/07/the-lecithin-in-liposomal-c.html

Now given there are basically four primary ingestibles required, two of which are literally FOODS (aminos and lipids, or proteins and fats) and the other two of which are smaller amounts of substances that tend to accompany them (vitamins and minerals); the idea that humans should be restricting themselves from one of the only two FOODS is literally insane.

I think that culturally we are literally starving to death en masse, while we are profoundly overfed en masse -- we are more like forcefed baby ducks ready to be given up for liver pate than anything. Women don't just need to ingest fats, everyone needs to ingest fats, particularly things like phospholipid fats, which make up part of every cell membrane in the body, every nerve sheath, 30% of the brain and so on. We get profoundly little of these things in the standard diet.

It is a tragedy that on top of already being malnutritioned over much of life, people are then additionally warned away from the healthiest fats there are. So they're eating canola oil rather than grass-fed butter. Not only does their body get no good construction materials from this but it gets even more negative stuff to deal with.

Eventually we have bodies of twinkie-fats and heavy metals and plastics and then we wonder why health starts to fail. Those are the construction materials we fed our bodies. Even plants and animals would begin failing to thrive fed this instead of healthy lipids and aminos. It isn't surprising that humans do.

PJ

[M Levac]

That's hilarious! So either you are thin, or you are an idiot. :lol: Actually I would say that attempting to survive in an environment better adapted to thinness might lead to even more development of other capacities in fat people as compensation. I am referring here to ordinary fat people over evolutionary time, not pathologically fat people like the present day of course.

PJ
That's a good point. It's like what S-piper said about menopause, where women who are fatter due to menopause aren't hampered by this extra fat, on the contrary the extra fat becomes an advantage as she explained, because their primary role now is to help with caring for the young. It also occurs to me that wisdom would be highly valued and protected within group dynamics. Wisdom comes with experience, experience comes with time, and time means growing old. So as long as growing fatter does not prevent growing old, it's not selected against.