Human body shape has sophisticated details and purposes. Shape or figure is defined mainly by skeletal structure, muscles and fat. Skeletal structure grows and changes only up to when a human grows adult and remains same for rest of lifetime. During puberty differentiation of male and female body occurs for the purpose of reproduction. In an adult human muscle mass may change due to exercises and fat distribution may change due to hormone fluctuations. Inherited genes induce details of body shape.

Body shape has effects on body postures and gait, and plays a major role in physical attraction between opposite sexes. This is because shape implies individual's hormone levels during his puberty which implies fertility, it also says about current levels of sex hormones. Good shape also implies good health and fitness of the body. Art of figure drawing defines body proportions that are considered as ideal.

Skeletal structure

Skeletal structure frames overall shape of the body. This remains almost the same in an adult human, and does not alter much during lifetime. Males are generally taller, but body shape is analyzed after normalizing with respect to height.

Comparison between a male (left) and a female pelvis (right). Females generally have wide hips. (Images not to scale.)

Broad shoulders and expanded chest (in males):Widening of shoulders occur as part of male pubertal process. Expansion of ribcage is caused by effects of testosterone during puberty. Hence males generally have broad shoulders and expanded chest. This is to allow for more room to inhale more air for muscles. Wider shoulder results a swagger in shoulders while males walk.Wide hips (in females):Widening of hip bones occur as part of the female pubertal process, estrogen (predominant sex hormone in females) causes widening of pelvis as a part of sexual differentiation. Hence females generally have wide hips. This is to allow for childbirth, the shape of a female pelvis is flatter, more rounded and proportionally larger to allow the head of the foetus to pass during childbirth. Sacrum in females is shorter and wider, also directed more backward(see image). This affects their walking style, resulting in hip sway, also, females generally stand with hips relaxed to one side. After puberty, females generally have hips wider than shoulders and males otherwise, which is considered as a secondary sex characteristic. But not everyone follows this stereotypical pattern. Both male and female hormones are present in body, though only either of them is predominant in an adult human, the other hormone has effect on shape to some extent.

Facial features

Due to the action of testosterone, males develop these facial-bones features during puberty:

• A more prominent brow bone.
• A squarer jaw.
• Larger nose bone.

Because females have around 20 times less testosterone, these features do not develop to the same extent, and smaller nose makes for fuller upper lip unlike males. Hence female faces are generally more similar to that of a pre-pubertal child.

Fat distribution, muscles and tissues

Body shape is affected by body fat distribution, which is correlated to current levels of sex hormones. Muscles and fat distribution may change from time to time, unlike bone structure, depending on food habits, exercises and hormone levels.

Fat distribution

Estrogen stores fat in the buttocks, thighs, and hips in women. When women reach menopause and the estrogen produced by ovaries reduces, fat migrates from their buttocks, hips and thighs to their waist, later fat is stored in the belly. Thus females generally have relatively narrow waist and big buttocks, and this along with wide hips make for their bigger hip section and lower waist-hip ratio, around 0.7

Estrogen increases fat storage in the body, which results more fat stored in body of females. Body fat percentage recommendations are more for females, this serves as an energy reserve for pregnancy. Males have less subcutaneous fat in face due to effect of testosterone, also testosterone reduces fat by aiding fat metabolism. Males generally deposit fat around waist and abdomen("apple shape") due to lack of estrogen.

Muscles

Testosterone helps build and maintain muscles through weight exercise. Males have around 20 times more testosterone than women. Prominent muscles of the body include the pectoral muscles,biceps and triceps in the arms and quadriceps in the thighs.

Breasts

Females have enlarged breasts due to functional mammary glands, developed due to the effect of estrogen since puberty. Mammary glands do not contain muscle tissue. The shape of female breasts is affected by age, genetic factors, body weight.

Overweight and underweight

Overweight and underweight cause change in shape as well as posture and walking style. Obesity or overweight also brings about noticeable change in shape of body, obesity is measured using BMI or waist circumference. Depending on the BMI, a body may be referred to as slim, overweight or obese.

Dieting, in conjunction with exercise, may by used to bring and keep the BMI within an acceptable range.

Fat and carbohydrates constitute the majority of energy factors of food and is measured cumulatively in the USA in kCals (which is customarily reported as Calories with a capital C) and in KiloJoules in the rest of the world. Though proteins are a major component of food consumed by humans, they mostly aid growth and repair of tissues and muscles and have comparatively little effect on weight control.

A Low-fat diet and a low-carbohydrate diet will both produce identical results.

Fitness and exercises

Different foms of exercises are practiced for fitness of body and also health. Different forms of exercises include yoga, aerobics, dancing. It was commonly believed that targetted exercise reduces fat in specific parts of the body -- for example, that exercising muscles around belly reduces fat in the belly. This, however, is now proven a misconception. But exercising reduces fat throughout the body, and where fat is stored depends on hormones. liposuction is commonly used surgery to remove fat from body. Other common methods include walking, jogging, cycling etc.

Clothing and accessories

Clothing or dresses enhances or even changes appearance of body. Fashion clothes enhance appearance of shape, while tight jeans, bikinis, bras, belts, corsets etc. hug body into their shape against gravity. High heeled sandals, generally used by females, also alter body proportions.

Dress size depends on different dimensions. US, European and international standards are considered dress size standards. Different terms used in dressing include Petite sizes, full-figured(FFW), Size zero, vanity sizing etc.

Types and terminologies

Classifications are mainly based on circumference of bust-waist-hip(BWH), like 34-24-36(inches) respectively. In this case waist-hip ratio is 24/36 = 0.67. Many terms or classifications are used to describe body shape types.

• V shape: Males tend to have proportionally smaller bottom, bigger chest and wider shoulder, which makes for V-shape of torso. V-shaped males are considered attractive.
• Hourglass shape: Females body is significantly narrower in waist both in front view and profile view. Waist is narrower than chest region due to breasts and than hip region due to buttocks, which resembles an hourglass.
• Apple: Belly region is bigger than hip section, mainly males.
• Pear or spoon or bell: Hip section bigger than upper body, mainly females.
• Rectangle or straight or banana: Hip section, waist and shoulder are straight.

Impact of body shape on health

According to Heart and Stroke Foundation of Canada, those people with a larger waist (apple shaped) have higher health risks than those who carry excess weight on the hips and thighs (pear shaped). People with apple shaped bodies who carry excess weight are at greater risk of high blood pressure, Type 2 diabetes and high cholesterol.

See also

• Human positions (postures)
• Human gait (walking style etc.)
• Human physical appearance
• Human skeleton

Notes