Final answer:
A healthy waist-to-tallness ratio is less than half of one's height, but the waist-to-hip ratio is a better predictor of health risks. Ratios above 0.85 for women and 0.90 for men suggest central obesity and increase the risk of chronic diseases.
Step-by-step explanation:
For the waist-to-tallness ratio, your waist should be less than half of your height to be considered healthy. However, the waist-to-hip ratio is often considered a better measurement than waist circumference alone in predicting disease risk. For example, a waist-to-hip ratio greater than 0.85 for women or 0.90 for men is diagnostic of central obesity. Central obesity indicates most of the excess fat is in the abdomen, resembling an apple shape, which is associated with greater health risks than a pear shape where fat is stored around the hips.
Observational studies have linked people with an apple-shaped body and a high waist-to-hip ratio to a greater risk of chronic diseases such as type 2 diabetes and heart disease compared to those with a pear-shaped body. Additionally, abdominal obesity as defined by the World Health Organization (WHO) correlates to waist-to-hip ratios above 0.90 for males and above 0.85 for females, indicating higher health risks.