Women with heftier hips and thighs test smarter, as do their kids; cognitive edge is attributed to the higher omega-3 levels in lower-body fat
by Craig Weatherby
People's perceptions of female beauty range widely across the world, and Western cultures' standards for womanly allure changed dramatically in the decades following World War II.
Nowadays, being thin is in, with the linear figures of top fashion models getting so slim as to incite official attempts to bar underweight models and their starvation-style diet regimens.
There's little doubt that women with smaller waists bigger hips and thighs—proportions that researchers call a “low waist-hip ratio”—have long constituted the female ideal.
From ancient India and Persia to classical-era Greece and Rome, up through the 19th century, portrayals of ideal women were curvaceous females with plump hips, ample thighs, and modest waists.
The voluptuous, curvaceous women portrayed by 17th century Dutch painter Peter Paul Rubens gave women of this body type the appellation “Rubenesque”. (Our point is illustrated by Ruben's famous "Venus in Front of the Mirror", above left.)
Fleshy, curvaceous Rubenesque women were the Western world's female ideal until well into the 20th century, and remain the acme of attractiveness in much of the modern world.
The results of new research suggest there's an evolutionary reason why men have long favored this particular type of female pulchritude.
In fact, most men associate the term pulchritude—which the dictionary defines simply as “female beauty”—with ample, curvaceous figures in the mode of Marilyn Monroe or Jennifer Lopez.
The new findings suggest that men's common misuse of the term reveals an ancient, evolution-driven yen for fuller figures, which seem to signal a smarter mate... and one who will produce brainier offspring to boot.
Study finds curvy women and their babies extra smart: Omega-3s seen as key
Periodically, the US Dept. of Health and Human Services conducts The National Health and Nutrition Examination Survey (NHANES) among American adults and children.
This large health survey is unique because it includes medical examinations and laboratory tests in addition to questionnaires about diet and lifestyle.
A new analysis of NHANES data has produced intriguing new findings that tie women's body shapes to their mental performance and their children's brain power.
Compared with abdominal fat and other upper-body fat, the fat in women's hips and thighs contains relatively higher proportions of omega-3 fatty acids: the kind of fat most important for brain development.
In contrast, abdominal fat and other upper-body fat is relatively low in omega-3s, and relatively high in omega-6 and saturated fats. These fats are, respectively, less important to brain development/performance, and possibly unhelpful to it. (See “Dietary Fat May Affect Kids' Memories”.)
Knowing that lower waist-hip ratios correlate with higher body stores of omega-3s, researchers at the University of California and the University of Pittsburgh used NHANES data to compare women's waist-to-hip ratios with their scores on cognitive (mental performance) tests, and with their children's scores on cognition tests. (Lassek WD, Gaulin SJ 2008)
A woman's waist-hip ratio (WHR) reflects the relative proportions of upper-body fat to lower-body fat, and the two researchers hypothesized that waist-hip ratio might predict cognitive ability of women.
Fetuses and breast-feeding infants rely on the fat stored in their mothers' bodies, so the researchers further hypothesized that a child's cognitive development should be optimized if his or her mother has a low waist-hip ratio.
Because women with relatively small waists and relatively large hips and thighs store higher body levels of omega-3s, their children should enjoy an edge when it comes to brain development.
The authors of the new study—UCSB professor Steven J.C. Gaulin and William D. Lassek of the University of Pittsburgh—stressed that their findings hold special implications for the health of teenage mothers and their unborn or nursing children.
Teenage mothers and their children compete for the omega-3s stored in the mother's body fat. This competition is threatening to mother and child alike, because both party's bodies and brains are still developing.
Drs. Gaulin and Lassek hypothesized that the higher omega-3 levels associated with lower WHRs should reduce the well documented risk of sub-optimal brain development among the children of teen mothers.
Rubenesque figures make women and their kids smarter
After controlling for the women's education level, income, and other possible confounding factors, the researchers concluded that every decrease of 0.01 in a mother's current waist-hip ratio increases their child's average cognitive score by 0.061 points.
Drs. Gaulin and Lassek also determined that lower waist-hip ratios (WHRs) are associated with higher cognitive scores and greater education advancement among women.
Interestingly, the researchers found that women with low WHRs also have lower average body-mass indices (BMI).
The BMI combines a person's height and weight measurements to provide a rough guide to their position on the spectrum from thin to obese.
Because women with low WHRs have lower BMIs, they generally have less body fat than women with high WHRs. This means that women with low WHRs have smaller energy reserves to support the energy demands of pregnancy and to increase survival chances in times of famine.
The researchers noted that this finding suggests that simple plumpness is not a major factor in male preferences for women with low WHRs.
Instead, they concluded that natural selection favors men's choice of women with low WHRs because these women's offspring will be a bit smarter than average: a difference that confers a survival advantage.
As they wrote, “…our present findings are clear: [a mother's] WHR predicts offspring cognitive ability, and [her] BMI does not” (Lassek WD, Gaulin SJ 2008).
The conclusions reached by Drs. Gaulin and Lassek should provide comfort to the large majority of women who do not fit the modern model for female beauty, which favors thin waists and scant body fat:
- “…women with lower WHRs and their children have significantly higher cognitive test scores, and teenage mothers with lower WHRs and their children are protected from cognitive decrements associated with teen births.”
- “These findings support the idea that WHR reflects the availability of neuro-developmental resources [omega-3s]
- “[these results] offer a new explanation for men's preference for low WHR” (Lassek WD, Gaulin SJ 2008).
So when women catch their husbands or boyfriends eyeing voluptuous women, they can remain cool, secure in the knowledge that males are involuntarily hard-wired to favor curvaceous women.
Of course, women are probably hard-wired to cold-shoulder mates who admire rivals too obviously. So realistically, we can only expect super-human female equanimity when pigs fly and Hades acquires a skating rink.
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