You know your SIN and probably a few PINs, but do you know your BMI?

BMI, or body mass index, is one of those figures that you hear tossed about in health circles. The number, which is your weight divided by the square of your height — it is much easier to get with a BMI calculator, found online — is used as a guideline to determine whether you are overweight or obese. While the measure is not perfect — muscle-heavy athletes might show a high BMI, for instance — it can be helpful in illustrating to people that they need to lose weight.

Another benchmarking tool is waist circumference. Re-search indicates that the place-ment of weight — where it is on the body — is an accurate indicator of future health problems.

So-called “pear” shapes are actually better off than the “apples” who carry their weight around their middles. The rule of thumb: women with a waist circumference of 35 inches or more and men with a waist circumference of 40 inches or more are at a higher risk of disease than their peers.

Howard Wenger, professor of exercise physiology at the University of Victoria, believes these figures can be motivating for some but don’t provide anything we don’t already know. “Do you need your BMI
or your waist measurement?” he asks. “What you really need is a mirror.” — WENDY CUTHBERT