Overweight but Healthy: "Fat But Fit?"

Statistics on the obesity epidemic are staggering: two-thirds of Americans are currently overweight or obese. A compilation of 89 separate studies, published in the March, 2009 issue of BMC Public Health, found significant links to 18 health issues, including type 2 diabetes, osteoarthritis, gallbladder disease and cancer. Yet several major research studies have shown that it might be possible to be overweight and healthy, or "fat but fit."

A fitness study by the non-profit Cooper Institute in Texas measured the body composition and cardiovascular fitness of 22,000 men ages 30-83. During eight years of follow-up, the mortality rates of overweight men were about the same as mortality rates of normal weight and fit men.

In 2004, a study of 900 American women who had experienced cardiovascular "events" such as heart attacks found that lack of exercise was a more reliable indicator of an adverse cardiovascular event than body weight. Another 2004 study published in the New England Journal of Medicine analyzed 20 years of data from the Nurse's Health Study, and compared mortality rates, physical activity and weight. The study concluded that physical activity lowered death rates across all weight categories from lean (Body Mass Index under 25) to obese (BMI of 30 or greater). Although physical activity did not completely eliminate the health risks associated with being overweight, it showed that active, overweight women with mid-range BMI levels had a lower risk of death than lean women who were inactive.

A 2010 study conducted by Glen Duncan at the University of Washington Department Of Epidemiology estimated the percentage of U.S. adults who could be considered fat but fit. The study of 4,675 adults (20-49 years old) compared BMI levels, gender, age-specific criteria and cardiovascular fitness. Overall, 8.9% of all subjects studied were considered obese with high levels of cardiovascular fitness, 17.4% were overweight with high levels of cardiovascular fitness, and 30% were normal weight with high fitness levels. These encouraging results demonstrated that even overweight or obese individuals could attain moderate to high levels of cardiovascular fitness.

Although exercise alone will not totally eliminate all of the health risks of being overweight, these studies show that moderate physical activity can offset some of the negative effects of excess weight on health. For some overweight individuals, it is possible to be both overweight and healthy, or "fat but fit."