Apple body shape - is the news all bad?

August 10, 2009 8:27 AM

What advantages are there to having an apple shape?

Studies have shown that having a fat storage pattern that favors the abdomen (the apple shape) rather than the buttocks and hips (the pear shape) carries an increased risk of diabetes, heart disease and general ill health. There's got to be an upside, right? Wouldn't evolution have taken the trait out if there weren't?

My googling is not the strongest and my searching has gotten me nowhere. What advantages can you think of to being an apple?

posted by terrierhead to health & fitness (24 comments total)

Wouldn't evolution have taken the trait out if there weren't?

Considering that until the industrial revolution food has generally been much more scarce than now, I'd have to say that "evolution" doesn't even apply here. There really aren't any health advantages to having and excess of visceral fat.
posted by Burhanistan at 8:38 AM on August 10 [1 favorite]

There really aren't any health advantages to having and excess of visceral fat.
Tell that to someone fighting cancer or any other wasting disease.
posted by kimdog at 8:41 AM on August 10 [3 favorites]

an increased risk of diabetes, heart disease and general ill health.

Yeah, I think this is the only contribution to evolution at work here.
posted by hermitosis at 8:42 AM on August 10 [1 favorite]

I don't know anything about apples-shapes, but one of your premises is wrong: evolution would not necessarily work against a trait that kills you when you're 60 rather than 70, i.e. long after procreating. If we assume that for the vast majority of human history life expectancy didn't go beyond 40 and people tended to have too little food rather than too much, you'll see that a fat storage pattern that kills you when you're 60 if you eat too much will not make the natural human unfit for surviving in the wild. We evolved fat storage in the first place to protect against lean times, I would assume. Heart disease was not a real factor.
posted by creasy boy at 8:43 AM on August 10 [4 favorites]

To expand what Burhanistan said...

Darwinian evolution requires the mechanism of "natural selection," which only works in re a natural environment.

The differences between humans and pretty much all other organisms is that we factor in choice-making and the ability to completely remove ourselves from the natural environment.

Id est humans, for all intents and purposes, aren't really part of Darwinian evolution anymore. (Seriously, if we were, there probably wouldn't be people with life-threatening food/latex allergies in existence.)

The only remotely possible advantage is thermal body physics. Time to move to Siberia?
posted by Ky at 8:45 AM on August 10

Having excess bodymass may help you fight cancer or any wasting disease where the 40% of bodyweight lost = death rule tends to apply, whether the fat is on the abdomen or butt/hips is irrelevant.
posted by zentrification at 8:45 AM on August 10 [1 favorite]

I definitely hear you about our food situation - large amount of high energy foods easily available - being unnatural. At the same time, the fat storage pattern is something that nature does determine. Taking obesity out of the equation, is there an advantage to the body type that stores fat on the abdomen rather than hips/buttocks/thights?

Personal disclosure - I used to be overweight but have lost more than 45 pounds and have kept it off. I have hip bones that jut out and still have a belly. Having had twins in autumn, 2007 may be a contributing factor. Still don't have a very good waist-hip ratio. There's got to be a silver lining, right?
posted by terrierhead at 9:00 AM on August 10

I think your question assumes something that cannot be assumed, which is that "determined by nature" = "there's a good reason for it."

That's not really the case. As long as a trait doesn't adversely affect your ability to procreate, it has a good chance of sticking around. There is no requirement that the trait have a function, or be advantageous.
posted by odinsdream at 9:10 AM on August 10

> Wouldn't evolution have taken the trait out if there weren't?

Only if it prevented carriers of that trait from successfully propagating their genes, whether through affecting the reproductive system, causing premature death, or diminishing the carriers' survival abilities. Problems like diabetes and heart disease can affect the young, but generally have their greatest impact on adults who have already passed their peak years of reproduction and nurturing.
posted by ardgedee at 9:16 AM on August 10

Apple-shape here, lucky me. I've done tons of research on this because I've wondered if there is an upside to the host of health issue I have. As far as I can tell, there isn't one, at least not in the modern world with food readily available. However, back in the hunting and foraging days, we apple shapes were better able to survive famine because we stored fat so efficiently and had our own built-in reserves.

More scientific studies aren't going to use the term apple shape, so that's not going to make for a good Google search. Studies done on the Pima Indians about insulin resistance will get you further. You might also find items of interest on the Weston Price Foundation website.

I've always been curious if there was a distinct genetic advantage (a la the sickle cell anemia gene and malaria immunity) in addition to the bit about surviving famine. I have nothing scientific to back this up, and I am only one subject, but for the record - blood testing has revealed that I have immunity to measles, mumps, and rubella, even though I have had none of the above and have no record of getting vaccinations for any of those.
posted by chez shoes at 9:33 AM on August 10

Id est humans, for all intents and purposes, aren't really part of Darwinian evolution anymore. (Seriously, if we were, there probably wouldn't be people with life-threatening food/latex allergies in existence.)

This seems bizarre to me--if humans are reproducing, aren't they still part of Darwinian evolution? That is, something like life-threatening allergies could be a genetic mutation; if it stops the affected individual from living to reproductive age/reproducing, it is "selected against." If not, it's a trait that's continued to be passed down. Or, essentially, what odinsdream said.

(You can argue that different traits are being selected for/against than would in an environment without the intervention of human science, but as long as some people are having babies and others not, I can't really see how we wouldn't still be evolving--imperceptibly slowly, of course.)

Anyway, back on topic--some studies have shown that those who are "overweight" (regardless of where they store their fat) have a longer life expectancy at 40 than those who are thin.
posted by PhoBWanKenobi at 9:33 AM on August 10

Darwinian evolution requires the mechanism of "natural selection," which only works in re a natural environment.

The differences between humans and pretty much all other organisms is that we factor in choice-making and the ability to completely remove ourselves from the natural environment.

Id est humans, for all intents and purposes, aren't really part of Darwinian evolution anymore. (Seriously, if we were, there probably wouldn't be people with life-threatening food/latex allergies in existence.)

BZZZZZT. This is completely wrong.

The "natural" in "natural selection" really has nothing to do with some sort of judged condition of the environment. It only means selective pressures external to the individual. Natural selection isn't something that can be switched off; rather, certain pressures can raise or lessen in intensity. True, now there are epinephrine pens for anaphylactic shock, but a peanut allergy will still kill people who don't have access to an epipen, who can't afford an epipen, who forgot their epipen that day, etc. So the pressure is still there, but weakened. On the other hand, most people in the developed world can get epipens when they need them, so the pressure may be relaxed so much that the trait can expand in the population. But we don't know; our science is not there and probably will never be (unless we completely map the genome of every living person. Not going to happen).

So, these traits probably aren't being removed from the population as quickly, but the pressures on them—or lack thereof—are still there. And other ones, too. Selection is still working because it's not a "thing," it's just a description of what happens. The problem is that because a human generation is so short, and we each only personally witness something like 3 in our lifetimes, we really have no idea what traits are being selected for now. Really, we need something on the order of thousands or tens of thousands of generation to see appreciable differences in a species. We don't need very many selective deaths per generation to enact a change, either. The evolution of horses was possible at an average of 5 selective deaths per generation, IIRC.

Moreover, Darwinian evolution isn't just natural selection. The other mechanisms—particularly genetic drift and mutation—are absolutely still working on humans, even in the (completely unlikely) case that selective pressures have reached absolute zero for all traits.

So, the take home for our OP: an apple shape wouldn't have been selected out of the population in the 200 years since industrialization began unless it killed everyone with an apple shape before they could have kids. Which is not the case, so it's still around. There may be some advantages to the apple shape, but even if we could wait around a few hundred thousand years, there would probably be no way of teasing out what exactly was being selected for or against and when.
posted by The Michael The at 9:49 AM on August 10 [2 favorites]

The only silver lining here is that you recognize you have an "apple shape" and that there are serious health consequences associated with it.

Use this to do something about it, try cutting wheat out of your diet for a few weeks, try reducing your stress levels, take something like phosphatidylserine that blunts the cortisol response to stress, change up how you exercise, go for long walks, get more sunlight, take naps.
posted by zentrification at 11:10 AM on August 10 [1 favorite]

I think the reason you get an apple shape is due to the way stress hormones affect fat deposition. During most of evolution, situations of chronic, extreme stress would have been typically been times in which you would need *every* calorie. So, probably, you are more likely to survive a famine or war or other situation of privation.

That's why cortisol puts the pounds there. And that would certainly have given your ancestors a survival advantage in many circumstances.
posted by Maias at 11:35 AM on August 10

No, it's not the case that we are at a narrow evolutionary optimum where every bad trait has a pleomorphic good aspect or even a good trait that's linked.

Natural selection is exceptionally weak in human history. We have until very recently had a small effective population size, which makes random drift more important and selection less. Similarly, consistently having enough to eat that you maintain a large fat pad over many years is relatively new, and therefore less important during most of our evolution. Most of those health consequences happen after breeding age or even typical lifespan of our ancestors, making them even less important.

Another thing to remember is that advantageous variation doesn't stick around very long; it tends to fix in a population (get so that everyone has it). Neutral (unimportant) and slightly bad variation will stay in a population much longer. There are situations where variation is maintained (frequency dependent selection, heterozygote advantage, temporary but routine population isolation), but those are exceptions rather than the rule.

When you see differences between closely related species (humans have a differently shaped pelvis from chimps and bonobos), it's natural to look for selection history to explain that. When you see variation in a population right now (some people have bad eyesight), it's more likely that it's either selection irrelevant, environmental, or slightly bad on its way out.
posted by a robot made out of meat at 11:43 AM on August 10

So, probably, you are more likely to survive a famine or war or other situation of privation.

Since we're speculating, how is that axiomatic? Having an extra 30 pounds in your belly really isn't going to translate into surviving a famine much longer. Also, if one is overweight and out of shape, that could mean that they will beaten to scarce resources by more lithe individuals. But it's hardly a truism that having inter-abdominal fat is going to help you survive.
posted by Burhanistan at 11:49 AM on August 10

We consume far more sugar than our ancestors ever did while they were "evolving". The USDA thinks we consume 130-150 pounds of added sugars (not including dietary sugar, including fruits) per person per year (page 24). For reference, that's roughly two thousand 250 gram apples in a year.

Exessive fructose is terrible for you, and also happens to be associated with increased intra-abdominal fat.
posted by zentrification at 12:27 PM on August 10

Please ignore everything said in this post about evolution except the stuff by The Michael The and a robot made out of meat (and please ignore the latter's "natural selection is exceptionally weak in human history" -- I'm not sure what that could even mean).

Evolution is a very good optimizer... a) over long periods of time, b) in a system with sufficient noise (to create mutations and to shock out of local maxima), and c) relative to a given environment. a) and c) are the issues here: as Burhanistan aptly points out, we, as a species, haven't spent very much time in an environment of extreme calorie abundance -- certainly not enough time for a disadvantageous trait in that environment to get weeded down or out.

Also, genes are funny things -- there's no 1-1 mapping of genes to traits. It could be that the "get abdominal fat" gene(s) is/are also the gene(s) that control some other, beneficial, trait.
posted by paultopia at 12:28 PM on August 10

I'm going to disagree with Burhanistan. I would say that it is definitely a truism that being able to store up calories when they're available in excess (e.g., summer time) will be selected for as long as there is a probability that without it, one might starve in lean times (e.g., winter) prior to reproducing. This would be true anywhere there is a winter or a dry season, but no refrigeration or agriculture. Part of Burhanistan's mistake is the assumption that there would be 30 extra pounds for long periods of time. First of all, it takes a long while and a lot of extra resources to get 30 extra pounds. Second, By the end of the winter/dry season, the people whose bodies stored 5 poulds of fat during the summer months would be the more lithe individuals. Emaciation is not fit. 1 pound of fat is about 3500 calories. So for each pound you can add a couple of extra days the individual could last when resources are scarce.

Regarding the question:

Until modern history, it is unlikely that a sufficient number of generations were able to live long enough to have their reproduction ability adversely affected by heart disease or adult onset diabetes to the point that evolutionary pressures would have changed the apple shape to a pear shape. Even in present day hunter/gatherer societies one wouldn't have a life expectancy much beyond 40. In more recent history (the last few thousand years or so in agricultural societies), I would imagine that as older men were able to propagate with women of childbearing age, there would be a slight pressure toward pear shapedness. Similarly, parents who live longer and in better health would be able to care for their offspring so if parents are able to regularly live past childbearing age (due, for example, to better diet, fewer lean times, and technology that extends life) then those who had stored fat in the pear shape would be better able to help their children secure resources to find mates as well as care for their grandchildren. So that would be another relatively new pressure towards a pear shape.

In the last 75 years or so (in western society) the pressure to store up fat has been removed, but that isn't nearly enough time to change human evolution as a whole significantly since we're really only talking about a couple of generations in only part of the world. That's really the crux of the answer to the question: Evolution is formed by generations and there just haven't been that many human generations where people lived long enough to see the benefits of a pear shape. This is especially true since a pear shape is a relatively weak pressure.

Another possible facet to the answer would be counter pressures towards apple shapedness. Even if the benefits were small, it would cut into the pressures toward a pear shape. I don't know of any benefit to the apple shape, but I'm also not a fat placement expert.

Also, on preview, I really like The Michael The's answer.
posted by Quizicalcoatl at 12:40 PM on August 10

Evolutionary pressures only apply before reproduction. Heart disease and diabetes are late onset disease. In the "natural" lifespan of a wild human, this would generally be after offspring were born.

Also, don't assume evolution makes any sense. It is random mutations plus fitness function. None of the solutions are necessarily optimal and none of them are ever complete (as the fitness function changes over time). We are still mutating and still dying off.
posted by chairface at 1:17 PM on August 10 [1 favorite]

Tell that to someone fighting cancer or any other wasting disease.

Not to be snarky, but visceral or belly fat is linked to inflammation...which is linked to cancer.

Belly fat wouldn't really give you any type of advantage if you have cancer...it could quite possibly be the cause.

Good luck.
posted by hal_c_on at 4:04 PM on August 10

Yay, evolution debate. I'd like to throw a few things in. . .

I remember the quote, "Evolution is a tinkerer, not a designer." So, I agree with the more eloquently put stuff about mutations, etc above.

Evolution doesn't account for things like cancer. One thing I remember learning about is how some characteristics that might be good design earlier in life might cause trouble later on. So some trait that could be related to cancer later in life, might be beneficial to a species earlier in life. We really weren't designed to life much past 25 or so. So, after that, it's all borrowed time anyway. Happy day!

Also, fat on the belly vs. fat on the butt/hips. . . Sex differences across a species are another component that plays a role in evolution. These are related to how much sperm a male creates, the type of tribes species live in (alpha male dominated/ monogamous / polyandry, etc).

So really, I think that evolution just doesn't have anything to do with the age group at risk, there is probably some belly fat advantage, and (like other said too) we didn't have the massive food access during the Era of Evolutionary Adaptation.
posted by No New Diamonds Please at 4:48 PM on August 10

Anecdotally, I've noticed that apple-shaped women often have broad shoulders, tiny butt cheeks, and relatively lean, muscular legs (Angelina Jolie and Rosario Dawson are good examples- those photos show them during "heavy" periods but even at their slimmest, their torsos are thick in comparison to their legs).

On the other hand, pear-shaped women often have narrow shoulders, big but cheeks, soft, tapered legs and are more likely to have cankles (Rihanna is a good example- she's tiny, yet her legs are soft and undefined).

So maybe "tendency to store fat in the belly" is just one very visible trait that could be frequently linked to some other traits (the way blond hair and blue eyes are often, but not always, linked since their alleles are close together or whatever)... and then maybe belly fat is part of a whole complement of related traits that are not visibly or intuitively obvious to the casual observer, but the effect is there nonetheless, and somehow it make a difference. Hell, maybe it's an enzyme or something molecular that we're not even aware of. Science can be pretty tiny.
posted by pseudostrabismus at 5:39 PM on August 10

You might be very interested in this article: The Figure-Flaw Paradox.

It is about this exact topic.
posted by Danila at 3:51 AM on August 11