Women and Body Fat (Ancestral Health Symposium 2013)

One of the best talks at the 2013 Ancestral Health Symposium was by Will Lassek, a retired doctor. Here’s the abstract:

One puzzle is why human males have such a strong preference for women with hourglass figures and low weights that can compromise fertility. The second is why slender young women typically have about one third of their weight in body fat, more than bears starting to hibernate, and why human infants are also very fat. Finally, why do women typically gain another twenty pounds or more during their reproductive years? The answer may lie in the roles that fat plays in providing essential fatty acids needed for the growth of a very large brain and in regulating overall fetal growth.

His answer to the first question was that death during childbirth was a serious danger. Women of lower weight give birth to babies with smaller heads — less likely to cause death. Wider hips means a larger birth canal. Women gain weight after their first birth because their birth canal is wider — the optimal baby size has gone up. A variety of data supported these ideas. Lessek’s answer to the first question is quite different than what evolutionary psychologists have said.

7 Replies to “Women and Body Fat (Ancestral Health Symposium 2013)”

  1. “One puzzle is why human males have such a strong preference for women with hourglass figures and low weights that can compromise fertility.” Does he assume that this is a long-standing preference or does he view it as a fashion for the last century or so?

  2. Actually, reflecting on the slender-to-the-point-of-anorexia models of the present, maybe I should be asking whether the hourglass figure has gone out of fashion in the last few decades.

  3. None of the discussion addresses the question “why human infants are also fat”. Was it addressed in the talk?

    I’d also like to add that the human male preference for an hourglass figure may be independent of the reproductive benefits. The hourglass figure may be a signal of femaleness.

    As a counter example, human males may have a preference for narrower jaws as a signal of femaleness and jaw width is probably independent of reproductive health.

    Seth: The “sign of femaleness” idea is interesting. There is also a preference for neoteny which leads to curious correlations. For example, female models have unusually baby-like faces.

  4. “One puzzle is why human males have such a strong preference for women with hourglass figures and low weights that can compromise fertility.”

    It has not always been so and even today is not so everywhere:

    > Stone Age female (possible fertility) “Venus figurines” are mostly “obese” (for example, see the famous Venus of Willendorf)

    > female steatopygia was traditionally valued by African Bushmen (fka “Hottentots”) and is similar to the aforementioned figurines, though not quite the same

    > ancient fertility goddess images were usually “fat”

    > there are/were traditional bride fattening practices and/or male preferences for “thicker” women in traditional societies in Africa, the Caribbean, and among African Americans, Hispanics, and perhaps others

    > Research suggests that skinniness is overrated, healthwise, and body fat excessively demonized: “Overweight people ‘live longer’ study claims,” http://www.nursingtimes.net/nursing-practice/clinical-zones/public-health/overweight-people-live-longer-study-claims/5053341.article

    > there is a human bias to assume that what is prevalent today has always been so and is perfectly natural, and it is often wrong

    “Those who have big legs and fat body, like arms too…, they look pretty when they wear grass skirts.” – Kitavan woman, Tribal Wives Kitava televison show, http://www.youtube.com/watch?v=0PfeXlwfWRg

    “I don’t want no woman with no skinny legs” – Joe Tex

  5. The Dr.’s name is spelled Lassek, for those interested in Googling him. He said “If you really want a low waist-hip ratio, you almost have to be skinny.” http://www.pghcitypaper.com/pittsburgh/a-conversation-with-william-lassek/Content?oid=1339427 That may be overemphasizing thinness. Groups in which women’s hips are naturally larger could have larger waists and achieve the same ratio and healthy body fat deposition to the hips and buttocks is another factor, not just thinness. I recall reading in the past that male preferences in at least one study were less about a small waist or thinness than waist/hip ratio at any body weight. Women were still seen as attractive even if they had larger waists as long as the preferred ratio was there. Also, there is apparently conflicting evidence even on WHR: http://psychsciencenotes.blogspot.com/2010/09/brief-rant-about-waist-to-hip-ratio.html

    Wouldn’t smaller heads also mean smaller brains and be a somewhat offsetting evolutionary disadvantage?

    Seth: Thanks for the correction. Heads grow. A smaller head in the beginning implies a smaller head only for a period of time. But, yeah, there are certainly trade-offs.

  6. Have you noticed how the answer is not an answer at all? If indeed there is a good reason for why women are fatter (and isn’t there always?) then why do men find it unattractive? My personal guess is that a strong torso usually means a strong body all over, and that having hard abs and all over strength are more common among people who are less fat and more active. When you’re healthy and energetic – and fertile – you don’t want to stay put in a chair doing nothing all day, getting fatter and weaker. Back in the days when even great beauties were fatter than today’s top models those same beauties also wore quite tight corsets that artificially emulate the look of a strong torso: straight back, narrow waist, flat stomach.

  7. Very thin women, due to anorexia, starvation, or excessive exercise, lose the ability to menstruate and thus become infertile. Our bodies are smarter than we are, therefore men who listen to their bodies gravitate toward women with a reasonable amount of fat deposits in their breasts and hips.

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