Female body shape or figure is the cumulative product of a woman's skeletal structure and the quantity and distribution of muscle and fat on the body. There are, and have been, wide differences on what should be considered an ideal or preferred body shape, both for attractiveness and for health reasons. These have varied among cultures simultaneously. As with most physical traits, there is a wide range of normality of female body shapes.
Human beings and their cultures have perennially focused attention on the female body as a source of aesthetic pleasure, sexual attraction, fertility, and reproduction.
The female body occurs in a range of shapes. The female figure is typically narrower at the waist than at the bust and hips, and usually has one of four basic shapes: banana, pear, apple, or hourglass. The bust, waist, and hips are called inflection points, and the ratios of their circumferences define these basic shapes. Usually, the bust area will depend on the person's weight and height.
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Estrogens have a significant impact on a female's body shape. They are produced in both men and women, but their levels are significantly higher in women, especially in those of reproductive age. Besides other functions, estrogens promote the development of female secondary sexual characteristics, such as breasts and hips.[1][2][3] As a result of estrogens, during puberty, girls substantially develop breasts and their hips widen. However, the presence of testosterone in a pubescent female inhibits breast development and promotes muscle development; while estrogens act in the other direction.
Estrogen levels also raise significantly during pregnancy. A number of other changes typically occur during pregnancy, including enlargement and increased firmness of the breasts, mainly due to hypertrophy of the mammary gland in response to the hormone prolactin. The size of the nipples may increase noticeably. These changes may continue during breastfeeding. Breasts generally revert to approximately their previous size after pregnancy, although there may be some increased sagging.
Some breasts are high and rounded, dome- or cone-shaped, and protrude almost horizontally from a female's chest wall. Such "high" breasts are common for girls and women in early stages of development. Over time, the sag on breasts tends to increase due to their natural weight, the relaxation of support structures, and aging. Breasts sag if the ligaments become elongated, a natural process that can occur over time and is also influenced by the breast bouncing during physical activity (see Sports bra).
Breasts can decrease in size at menopause if estrogen levels decline.
Estrogens can also affect the female body shape in a number of other ways, including increasing fat stores, accelerating metabolism, reducing muscle mass, and increasing bone formation.
Estrogens cause higher levels of fat to be stored in a female body.[4][5] It also affects body fat distribution,[6] causing fat to be stored in the buttocks, thighs, and hips in women,[7][8] but generally not around her waist, which will remain about the same size as it was before puberty. The hormones produced by the thyroid gland regulate the rate of metabolism, controlling how quickly the body uses energy, and controls how sensitive the body should be to other hormones. Body fat distribution may change from time to time, depending on food habits, activity levels and hormone levels.
When women reach menopause and the estrogen produced by ovaries declines, fat migrates from their buttocks, hips and thighs to their waists;[9] later fat is stored at the abdomen.[10]
Body fat percentage recommendations are higher for females, as this may serve as an energy reserve for pregnancy. Males have less subcutaneous fat in their faces due to the effects of testosterone;[11] testosterone also reduces fat by aiding fast metabolism. The lack of estrogen in males generally results in less fat deposit around waists and abdomens (producing an "apple shape").
Testosterone is an anabolic steroid which helps build and maintain muscles with physical activity, such as exercise.[12] The amount of testosterone produced varies from one individual to another, but on average, an adult female produces around one-tenth of the testosterone of an adult male, but females are more sensitive to the hormone.[13] The muscles most likely to be affected are the pectoral muscles, biceps and triceps in the arms and quadriceps in the thighs.
On the other hand, estrogens reduce muscle mass. Muscle mass changes over time as a result of changes in testosterone and estrogen levels and exercise, besides other factors.
The circumferences of a woman's bust, waist, and hips, and their ratios, are used to define her basic shape. These are sometimes described as banana, pear, apple, or hourglass shapes,[14] though other shortcut terms are also used.
The bust is measured across the fullest part of a woman's breasts, generally across the crest of the breast while wearing a properly-fitting brassiere; the waist is measured at the smallest circumference of the abdomen; and the hips are measured at the largest circumference of the hips and buttocks.
It is said that the female body usually inflects inward towards the waist around the middle of the abdomen between the costal margins and the pelvic crests. The waist is typically smaller than the bust and hips, unless there is a high proportion of body fat distributed around it. How much the bust or hips inflect inward, towards the waist, determines a woman's structural shape. The hourglass shape is considered by many cultures to be the ideal or usual female shape, though only about 8% of women have this shape.[14]
Independent of fat percentage, weight or width, female body shapes are categorised into one of four elementary geometric shapes,[14] though there are very wide ranges of actual sizes within each shape:
A study of the shapes of over 6,000 women, carried out by researchers at the North Carolina State University circa 2005, found that 46% were banana (rectangular), just over 20% pear, just under 14% apple, and 8% hourglass.[14] Another study has found "that the average woman's waistline had expanded by six inches since the 1950s" and that today's women are taller and have bigger busts and hips than those of the 1950s.[14]
A woman's "dimensions" are often expressed by the circumference around the three inflection points. For example, "36-29-38" in imperial units would mean a 36" bust, 29" waist and 38" hips.
A woman's bust measure is a combination of her rib cage and breast size. For convenience, a woman's bra measurements are used. For example, though the measurements are not consistently applied, a woman with a bra size of 36B has a rib cage of 31-32 inches in circumference and a bust measure of 37-38 inches; a woman with a bra size 34C has a rib cage of 29-30 inches around, but the same bust measure of 37 inches. However, the woman with a 34C breast size will appear "bustier" because of the apparent difference in bust to ribcage ratio.
Height will also affect the appearance of the figure. A woman who is 36-24-36 at 5 ft 2 in (1.57 m) height will look different from a woman who is 36-24-36 at 5 ft 8 in (1.73 m) height. Since the taller woman's figure has greater distance between measuring points, she will likely appear thinner or less curvy than her shorter counterpart, again, even though they both have the same BWH ratio and the same weight. This is because the taller woman is actually thinner as expressed by her lower BMI, or body mass index, used to measure body weight in relation to height.
The use of BWH measurements for anything other than garment fitting is thus something of a shell game when applied to social body acceptance and evaluation. BWH is an indicator of fat distribution, not fat percentage.
The British Association of Model Agents (AMA) says that female models should be around 34-24-34 (86-60-86 cm) and at least 5 ft 8 in (1.73 m) tall.[15]
The aging process has an inevitable impact on a person's body shape. A woman's sex hormone levels will affect the fat distribution on her body. According to Dr. Devendra Singh, "Body shape is determined by the nature of body fat distribution that, in turn, is significantly correlated with women's sex hormone profile, risk for disease, and reproductive capability."[16] Concentrations of estrogen will influence where body fat is stored.[17]
Before puberty both males and females have a similar waist-hip ratio.[16] At puberty, a girl's sex hormones, mainly estrogen, will promote breast development and a wider pelvis tilted forward for child bearing, and until menopause a woman's estrogen levels will cause her body to store excess fat in the buttocks, hips and thighs,[17][18] but generally not around her waist, which will remain about the same size as it was before puberty. These factors result in women's waist-hip ratio (WHR) being lower than for males. During and after pregnancy, a woman experiences body shape changes. After menopause, with the reduced production of estrogen by the ovaries, there is a tendency for fat to redistribute from a female's buttocks, hips and thighs to her waist or abdomen.[19]
Each society develops a general perception of what an ideal female body shape would be like. These ideals are generally reflected in the art and literature produced by or for a society, as well as in popular media such as films and magazines. The ideal or preferred female body size and shape has varied over time and continues to vary among cultures;[20] but a preference for a small waist has remained fairly constant throughout history.[21] A high waist-hip ratio has often been seen as a sign of good health and reproductive potential.[22]
A low waist-hip ratio has also often been regarded as an indicator of attractiveness of a woman, but recent research suggests that attractiveness is more correlated to body mass index than waist-hip ratio, contrary to previous belief.[23][24] Historically, according to Devendra Singh,[25] there was a trend for slightly larger women in the 17th and 18th centuries, as typified by the paintings of Rubens, but that in general there has been a preference for a slimmer waist in Western culture. He notes that "The finding that the writers describe a small waist as beautiful suggests instead that this body part - a known marker of health and fertility - is a core feature of feminine beauty that transcends ethnic differences and cultures."[21]
New research suggests that apple-shaped women have the highest risk of developing heart disease, while hourglass-shaped women have the lowest.[26] Diabetes professionals advise that a waist measurement for a woman of over 80 cm (31 in) increases the risk of heart disease, but that ethnic background also plays a factor. This is because body fat buildup around the waist (the apple shape) poses a higher health risk than a fat buildup at the hips (the pear shape).[27]
Compared to males, females generally have relatively narrow waists and large buttocks,[28] and this along with wide hips make for a wider hip section and a lower waist-hip ratio.[29]
Notwithstanding wide cultural differences, researchers have confirmed that the waist-hip ratio (WHR) for a female very strongly correlates to the perception of attractiveness across all cultures.[30] Women with a 0.7 WHR (waist circumference that is 70% of the hip circumference) are rated more attractive by men in various cultures.[16] Such diverse beauty icons as Marilyn Monroe, Sophia Loren, and the Venus de Milo all have ratios around 0.7.[31] In other cultures, preferences vary,[32] ranging from 0.6 in China,[33] to 0.8 or 0.9 in parts of South America and Africa,[34][35][36] and divergent preferences based on ethnicity, rather than nationality, have also been noted.[37][38]
The WHR is also shown to have a very high correlation to female fertility, thereby unknowingly guiding men's evolutionary choices.[39]
WHR has been found to be a more efficient predictor of mortality in older people than waist circumference or body mass index (BMI).[40]
A woman's body shape is an aspect of her physical appearance, and impacts on her body image. Studies conclude that women are more worried about their body image than men [41] and that their concern can impact on their health.[42] Other studies have found that females tend to think more about their body shape and endorse thinner figures than men even into old age.[43] Commentators note that people who have a low body image will try to alter their body in some way, such as by dieting, or undertaking cosmetic surgery.
Various strategies are sometimes employed to temporarily or permanently alter the shape of a body. The most common include dieting and exercise.
At times artificial devices are used or surgery is employed. Breast size can be artificially increased or decreased. Falsies, breast prostheses or padded bras may be used to increase the apparent size of a woman's breasts, while minimiser bras may be used to reduce the apparent size. Breasts can be surgically enlarged using breast implants or reduced by the systematic removal of parts of the breasts.
Historically, great efforts have been made to reduce a woman's waist line. The use of boned corsets, for example, was practiced for several centuries. The corset reached its climax during the Victorian era. In twentieth century these corsets were mostly replaced with more flexible/comfortable foundation garments. Where corsets are used for waist reduction, it may be temporary reduction by occasional use or permanent reduction by people who are often referred to as tightlacers. Liposuction and the new and improved method liposculpture are common surgical methods for reducing the waist line.
Padded control briefs or hip and buttock padding may be used to increase the apparent size of hips and buttocks. Buttock augmentation surgery may be used to increase the size of hips and buttocks to make them look more rounded.