What determines a person's body shape?

As kids, we're all basically the same shape. So what changes? It all comes down to sex hormones, which regulate how you use and store fat. The big gender difference comes in the form of the classic apple and pear shapes (called gynoid and android). Testosterone stimulates fat deposits in the belly and inhibits it in the thighs, which is why men are typically apples, and estrogen inhibits fat in the belly and stores it on the thighs, which is why women are typically pears.
There's also an evolutionary reason for this: Fat deposits on the thighs are almost exclusively used during late pregnancy and when a woman is nursing. In eras when men and women all needed fat storage during times of famine, the fat deposits on thighs (as opposed to the belly deposits on men) helped women provide calories not just for themselves, but for their offspring as well.
An additional evolutionary advantage of why women are shaped like pears: The shape remains constant whether viewed from front, behind, or side. Some researchers have argued the front view is more important (under the assumption that breast size signals reproductive value, though it's also been shown that breasts do not always accurately reflect the reproductive capability of a woman). So this might magnify the sexual attractiveness of a woman who has shapely breasts and broad hips set against a narrow waist (the hourglass).

Find out more about this book: You: Being Beautiful - The Owner's Manual to Inner and Outer Beauty

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