To me this is a big flaming sack of duh, but I still think it’s fantastic. To summarize the study-related parts:
Even before last summer’s pronouncement of an obesity emergency, researchers had reported different findings in a study published in December 2007 in the Journal of the American Medical Association (JAMA). The study found that fitness—in this case the ability to walk quickly on a treadmill for a few minutes or longer—was a better predictor of who would die, and when, than BMI.
The study followed 2,600 adults over age 60 for 12 years. Participants were asked to walk on a treadmill at a quick walking pace, with a gradually increasing incline. Based on the results of the treadmill test, they were then put in five fitness categories, from least to most fit.
Researchers found that the least fit, regardless of BMI, were four times more likely to die during the course of the study than the most fit. But the most surprising difference in mortality was between the least fit group and the one just above that, who were half as likely to die during the study. In other words, just a little fitness could be twice as good as no fitness at all.
When the results were adjusted for other factors, such as smoking and age, fitness still mattered most.
So is it fitness, rather than fatness, that really counts? “That’s what we keep finding,” says Steven N. Blair, a coauthor of the JAMA study, and professor of exercise science and of epidemiology and biostatistics at the Arnold School of Public Health at the University of South Carolina. Clinical trials under way on the benefits of fitness will likely show that physical activity preserves brain health, too, Blair adds, meaning fitness may also lower the risk of dementia.
Another study of 5,400 adults, published in August 2008 in the Archives of Internal Medicine, found that fully half of overweight and one-third of obese participants were “metabolically healthy,” meaning they had few, if any, risk factors for heart disease, such as high blood pressure or low levels of “good” cholesterol. On the other hand, about a quarter of “normal”-weight people were metabolically unhealthy and exhibited cardiovascular risk factors. This study did not measure the fitness levels of the participants.