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.
Physical attractiveness
Both men and women judge women with smaller waist-to-hip ratios more attractive. Ethnic groups vary with regard to their ideal waist-to-hip ratio for women, ranging from 0.6 in China, to 0.8 or 0.9 in parts of South America and Africa, and divergent preferences based on ethnicity, rather than nationality, have also been noted. A study found the Machiguenga people, an isolated indigenous South American ethnic group, prefer women with high WHR (0.9). The preference for heavier women, has been interpreted to belong to societies where there is no risk of obesity.