The validity of the BMI measurement tool has long been a point of contention among health professionals and consumers alike. A new report will not only cast further doubt, but actually go one step further: overweight people may live longer than their “normal” weight counterparts.
According to the report involving nearly three million people from nearly 100 studies, those who were overweight had a lower risk of death than people who were normal weight, defined as a BMI range of 18.5 – 25.
“Fat per se is not as bad as we thought,” said Dr. Kamyar Kalantar-Zadeh, professor of medicine and public health at the University of California, Irvine, in a story at New York Times.
While that may sound controversial, the fact of the matter is that health is often so much more complex than we’d like. Weight is but one factor in our health. You may be heavy with normal blood pressure, or thin with dangerously high cholesterol or blood sugar levels.
Here’s a breakdown of the mortality risk for each group in the study, relative to the normal weight class: there was a six percent lower risk of death for overweight; an 18 percent higher risk of death for obesity; a five percent lower risk of death for grade one obesity; and a 29 percent increased risk of death for grades two and three obesity.
The researchers give the following theories for the surprising results:
“Possible explanations have included earlier presentation of heavier patients, greater likelihood of receiving optimal medical treatment, cardioprotective metabolic effects of increased body fat, and benefits of higher metabolic reserves.”
In other words, since heavier people have visible signs of potential health risks, they may be more apt to see a doctor and be recommended medications that improve or control obesity-related symptoms (diabetes, high blood pressure, high cholesterol). Conversely, a thin person could be lulled into assuming they are healthy, when there are underlying issues that don’t depend on a person being obese. This is often referred to as “skinny fat.”
A study like this may have unintentionally negative consequences. Unfortunately, the general public may filter out the “messy” details and simply focus on what stands out most from the story: being overweight isn’t bad. The study also piles on more confusion, which encourages people to throw in the proverbial towel.
Health is a very complex subject matter, involving many different factors. For instance, this study focused on mortality rates. But what about quality of life? If you live a relatively long life overweight, but start to have issues with arthritis, joint problems, or other issues related to an unfit body, is that the life we all aspire for?
No one should confuse the study’s message as saying being heavy is a healthier alternative to thin. If anything, it’s an indictment of the flawed BMI methodology.
January 4th, 2013