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
Gynoid fat is primarily a store of energy to be utilised in the nurturing of offspring, both to provide adequate energy resources during pregnancy and for the infant during the stage in which they are breastfeeding. When there are insufficient energy resources in the environment or health issues which require energy to combat a woman's storage of gynoid fat is likely to be reduced. Therefore, ancestrally, a female with high levels of gynoid fat would be signalling to males that they are in an optimal state for reproduction and nurturing of offspring. This can be seen in the fact that a female's Waist–hip ratio is at its optimal minimum during times of peak fertility - late adolescence and early adulthood, before increasing later in life.