Waist-to-Hip Ratio in Women and the Storage of Fat as a Sexual Selection Strategy

Men are attracted to women with a waist-to-hip ratio that indicates both fitness and the ability to bare children; therefore, women of the age of puberty begin to store fat in their breasts and hips to give the illusion of such a ratio.

Folksonomies: evolution sexual selection

The Waist-to-Hip Ratio

Why does the waist-to-hip ratio matter? Singh observes that a \"gynoid\" fat distribution—more fat on the hips, less on the torso—is necessary for the hormonal changes associated with female fertility. An \"android\" fat distribution-—fat on the belly, thin hips—is associated with the symptoms of male disabilities such as heart disease, even in women. But which is cause and which effect? It seems to me more likely that both the shape and the hormonal effects of it are sexually selected by generations of males rather than males preferring the shape because it is the only way the hormones can be made to work. The relatively brief period during which women have hourglass bodies—from fifteen to thirty-five, say—is a sexually selected phenomenon. It owes more to competition to attract men than to any other biological need. Men have been unconsciously acting as selective breeders of women.

Low provides one possible reason for the male preference tor a low ratio—choosing broad-hipped women more able to give birth. Most apes give birth to babies whose brain is half-grown; human babies\' brains are one-third grown at birth, and they spend far less time in the womb than is normal for a mammal, given the longevity of man. The reason is obvious: Were the hole in the pelvis through which we are born (the birth canal) commensurately larger, our mothers would be unable to walk at all. The width of human hips reached a certain point and could go no further; as brains continued to grow bigger, earlier birth was the only option left to the species. Imagine the evolutionary pressure of this process on female hip size. It was always wise for a man to choose the biggest-hipped woman he could find, generation after generation, for millions of years. At a certain point hips could get no bigger but men still had the preference, so women with slender waists who appeared to have larger hips by contrast were preferred instead.


Men are unconsciously directing the evolution of women.

Folksonomies: evolution sexual selection gender sexual diversity

Cause and Effect

Why Women Store Fat in their Hips and Breasts

Low was looking to explain why young women have fat on their breasts and buttocks more than on other parts of their bodies. The reason this requires explaining is that young women are different from other human beings in this respect. Older women, young girls, and men of all ages gain fat on their torsos and limbs much more evenly. If a woman of twenty or so gains weight, it largely takes the form of fat on the breasts and buttocks; her waist can remain remarkably narrow.

So much is undisputed fact. What follows is entirely conjecture, and it was a conjecture that caused Low a good deal of sometimes vicious (and mostly foolish) criticism when she published the idea in 1987

Twenty-year-old women are in their breeding prime; therefore, the unusual pattern of fat distribution might be expected to be connected with getting a mate or bearing children. Standard explanations concern the bearing of children; for example, fat is inconvenient if it competes for space about the waist with a fetus. Low\'s explanation concerns the attraction of mates and takes the form of a Red Queen race between males and females. A man looking for a wife is likely to be descended from men who found two things attractive (among many others): big breasts, for feeding his children, and wide hips, for bearing them. Death during infancy due to a mother\'s milk shortage would have been common before modern affluence—and still is in some parts of the world. Death of the mother and infant from a birth canal that was too narrow must also have been common. Birth complications are peculiarly frequent in humans for the obvious reason that the head size of a baby at birth has been increasing quickly in the past 5 million years. The only way birth canals kept pace (before Julius Caesar\'s mother was cut open) was through the selective death of narrow hipped women.

Grant, then, that early men may have preferred women with relatively wide hips and large breasts. That still does not explain the gaining of fat on breasts and hips; fat breasts do not produce more milk than lean ones, and fat hips are no farther apart than lean ones of the same bone structure. Low thinks women who gained fat in those places may have deceived men into thinking they had milkful breasts and wide hip bones. Men fell for it— because the cost of distinguishing fat from heavy breasts or of distinguishing fat from wide hips was just too great, and the opportunity to do so was lacking. Men have counterattacked, evolutionarily speaking, by \"demanding\" small waists as proof of the fact that there is little subcutaneous fat, but women have easily overcome this by keeping waists slim even while gaining fat elsewhere.


Young women deceive men about their sexual fitness with fat to make their hips look wider and their breasts larger.

Folksonomies: evolution sex evolutionary strategy sexual