Waist–hip ratio
WHR is used as a measurement of obesity, which in turn is a possible indicator of other more serious health conditions. The WHO states that abdominal obesity is defined as a waist-hip ratio above 0.90 for males and above 0.85 for females, or a body mass index (BMI) above 30.0. The National Institute of Diabetes, Digestive and Kidney Diseases (NIDDK) states that women with waist-hip ratios of more than 0.8, and men with more than 1.0, are at increased health risk because of their fat distribution.
Gynoid fat distribution
Android fat distribution is also related to WHR, but is the opposite to gynoid fat. Instead, android fat is deposited in the waist, breasts, buttocks and thighs, but can give an unattractive appearance, as it gives women a ‘T-shaped” body and is more lumpy. The ratio of a woman’s gynoid to android fat is used to measure her WHR, whereby the lower the WHR, the higher gynoid to android fat ratio, which is perceived as more attractive for women. As women with higher levels of gynoid fat distribution are seen as more attractive, this enables them to access highly desirable male mates. WHR is related to various markers of health and fertility, for example a high WHR is correlated with: a low estrogen/testosterone ratio (this means that a woman has more of a 'T-shaped' body which is seen as less healthy and attractive); a high ratio is also correlated to circulatory system problems such as heart attacks and strokes; more disease (e.g. cancer); and is a general sign of increased age and hence lower fertility, therefore supporting the adaptive significance of an attractive WHR. This advantage of being more fertile has been supported by various studies, for example artificial insemination studies involving sperm donors, where the best predictor of success is a low WHR. Similarly, a high WHR has been associated with impairment in the pregnancy rate of IVF (in vitro fertilisation) embryo transfer women due to the higher levels of android fat distribution. Further studies have also found that oestrogen replacement in women lowers the WHR in pre- and post-menopausal women, and that this is because oestrogen replacement maintains gynoid fat distribution in the body.