The simple Waist-Height ratio actually predicts the risk of heart disease better than the complex BMI (See the Research Summary Page). This is probably because belly fat is measured, rather than overall body fat -- and belly fat is the better indicator of future coronary problems.

Another plus for the Weight-Height Ratio is that the BMI is notoriously inaccurate for people with unusual amounts of muscle. More specifically, mathematical estimates of the BMI in such people are inaccurate -- a physical test, such as electrical impedence or submersed weight, will generate a valid BMI even for a professional bodybuilder or extreme anorectic.

The biggest downside of the ratio is that it depends upon an accurate and standardized waist measurement, preferably accurate to .25 inch or 1 cm. This is surprisingly hard to do -- the waist is difficult to measure accurately: 1) A person can voluntarily shrink or expand the waist by 5-15%; 2) The measuring process itself can compress the waist, especially in chubbier subjects; and 3) the place where the waist is measured, even by professional researchers, varies from just above the top of the ileal crest (the bony projections at the top of your hips) to 1 inch above the navel, which can create wide variations in "waist size".

There are a number of research articles synopsized on the Research Page.

   Greek sculptors proposed the first objective standard for the human form around 400 BC. The second well-known attempt is found in Leonardo da Vinci's notebooks, from the Italian Renaissance (@1500 AD). In modern times, the question has become one more sought by bodybuilders -- who must have standards of judging for competition -- than by artists. In 1918, a pamphlet titled How Much Should I Measure and How Much Should I Weigh? was published by the Milo Barbell Co.

   Weight/height as an objective measure was introduced by David Willoughby, one of the great bodybuilders of the early 20th century. Willoughby was obsessed with physical proportion and spent his life collecting detailed and accurate records of atheletes' measurements. He eventually discovered the importance of comparing weight to height empirically. Using his empirical methodology, Willoughby arrived at an "ideal" proportion of 45.84% height-to-weight (using inches and pounds) for the athletic male. He also derived at figure of 57.7% as the point at which obesity became "morbid", or highly dangerous to general health -- impressively close to the World Health Organization's current "Substantially Increased Risk" percentage for men, 58.2%.

   The validity of Willoughby's observations has been substantiated by modern science using more experimental (but still inductive) methodology. While lacking many tools available to the modern scientist, Willoughby did have the advantage of rigidly standardized waist measurement, sadly missing today. We are also much closer to a theoretical understand of why the measurement is uniqely valid: Fat around the waist is more predictive of coronary disease than overall fat. The exact biochemical cause of this observation, however, is still undetermined. The impact overall body fat has on other health issues, particularly its relation to adult-onset diabetes, is better measured by other methods such as the BMI.