The news is aflutter this morning with reports of a new study in The New England Journal of Medicine (NEJM) which claims that being even a few pounds overweight ups your risk of premature death. What got scant coverage was all the new medical literature casting doubt on the scientific underpinnings of this NEJM study.
Just last week the prestigious British medical journal The Lancet published a Mayo Clinic review of 40 obesity studies which found that “overweight” is in fact the healthiest weight category, with a lower risk of death than being “normal” and “obese” (let alone “underweight” or “morbidly obese”). This corroborates the findings of a major study we talked about last year by researchers from the Centers for Disease Control and Prevention (CDC), which found that being overweight has a protective effect against untimely death. Since the Lancet study provided positive news, did it get much media attention? Take a guess.
What needs a lot more attention is the heavy criticism recently levied against the Body Mass Index, the simple measure of height and weight that many obesity studies use to classify people as “normal,” “overweight,” or “obese,” including the NEJM study. An article by Dr. David Cundiff in the International Journal of Obesity concludes: “I suggest abandoning the use of the BMI as a surrogate for physical inactivity and poor diet.” And a comment by Dr. Maria Franzosi in The Lancet declared: “BMI can definitely be left aside as a clinical and epidemiological measure of cardiovascular risk.” Indeed, as a measure that ignores muscle mass (and thus calls President Bush “overweight” and Governor Schwarzenegger “obese”), not to mention the question of where in the body fat is located, the BMI clearly has some serious flaws.
Even before it was processed, this new NEJM study’s data was a little sketchy. As Tufts obesity expert Aviva Must told The Boston Globe, the study “used participants’ own reports of their height and weight” (emphasis added).
