September 8, 2004
New Study: Fitness (Not Fatness) Is Key
"Our study shows that the lack of physical fitness is a stronger risk factor for developing heart disease than being overweight or obese," says one author of a new report in JAMA (the Journal of the American Medical Association). This emphasis on fitness as opposed to weight stands as an important rebuttal to the food cops and their calls for "fat taxes," regulations and even lawsuits to force us into thinner bodies. Crucially, the authors of the JAMA study warn: "Focusing on weight loss alone fails to directly address the related but more important lack of physical fitness among overweight individuals."
Taking a direct stab at previous research that overemphasizes people's waist lines, the JAMA article notes that "most studies" of the flawed Body Mass Index (BMI) standard "and other measures of obesity have not adequately accounted for physical fitness." Says who? The authors hail from the National Institutes of Health, the University of Florida College of Medicine, the University of Pittsburgh Medical Center, the Rhode Island Hospital, the Atlanta Cardiovascular Research Institute, and the Cedars-Sinai Medical Center.
A second study -- co-authored by Center for Science in the Public Interest (CSPI) scientific advisory board member JoAnne Manson and published in the same issue of JAMA -- claims that weight (as measured by BMI) is more closely associated with type 2 diabetes than is physical activity.
But an accompanying editorial by Dr. Steven Blair notes that Manson's study may have resulted in the "misclassification" of some important variables. Blair also suggests that the measure of physical fitness was more accurate in the heart disease study than in Manson's. Finally, he adds that Manson's methodology has not been "validated with a gold standard."
Of course, the real gold standard of the fitness-versus-fatness debate is still overall mortality. And here, the evidence is overwhelming. The authors of the most recent JAMA study take note of the substantial body of academic literature on the importance of fitness, rather than fatness. They write:
Our data supports previous studies showing that functional capacity [fitness] appears to be more important than BMI for all-cause and [cardiovascular] mortality, especially in women.Blair himself found that "active obese individuals actually have lower morbidity and mortality than normal weight individuals who are sedentary." And the authors of an American Journal of Clinical Nutrition study concluded: "For long-term health benefits we should focus on improving fitness by increasing physical activity rather than relying on diet for weight control." Notice that the experts call for physical fitness, not fat taxes.
Taking a run at the real issue, Blair told the St. Petersburg Times: "I think people are simply spending more time sitting than they did 15 or 20 years ago." He's right. Thirty years ago, 66 percent of children walked to school; that number has now fallen to 13 percent. Coal miners now sit at desks as data miners. And channel surfing has become the national sport.
According to the CDC, only "15 percent of U.S. adults engage regularly (3 times a week for at least 20 minutes) in vigorous physical activity during leisure time." It also reports that "60 percent -- well over half -- of Americans are not regularly active ... Worse yet, 25 percent of Americans are not active at all."
