Waist–hip ratio
The waist-hip ratio or waist-to-hip ratio (WHR) is the dimensionless ratio of the circumference of the waist to that of the hips.
This is calculated as waist measurement divided by hip measurement (W ÷ H). For example, a person with a 30″ () waist and 38″ () hips has a waist-hip ratio of about 0.78.
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.