Anybody who tracks their own weight and level of fitness is familiar with BMI (Body Mass Index). It’s a number determined by dividing one’s weight in pounds by one’s height in inches squared, and multiplying the result by 703, and it’s designed to indicate whether or not people are underweight, overweight, obese, or just right. And although BMI is a ubiquitous measure used by insurance companies to set premiums, pharmaceutical companies to push diet pills, and by physicians to advise patients about weight loss and weight gain, there has been strong evidence for some time that the whole concept is just bogus.
According to Mother Jones, “A higher BMI doesn’t necessarily mean you’re less healthy. In fact, patients with heart disease and metabolic disorders whose BMIs classify them as overweight or mildly obese survive longer than their normal and underweight peers. A 2013 meta-analysis by the National Center for Health Statistics looked at 97 studies covering nearly 3 million people and concluded that those with overweight BMIs were 6 percent less likely to die in a given year than those in the normal range. These results were even more pronounced for middle-aged and elderly people. This is known as the obesity paradox. “The World Health Organization calls BMIs of 25 to 29.9 overweight,” says Paul McAuley, an exercise researcher at Winston-Salem State University. “That is actually what is healthiest for middle-aged Americans.”
But regardless of BMI’s usefulness as a measure of overall health, that doesn’t mean it’s not a good idea to exercise properly. So read this while you’re on your way to the gym or as you’re going out for a nice long walk.