Fat or Fit: What Is More Important?

The prevalence of obesity is increasing worldwide, and obesity represents one of the major health hazards (1). Obesity was shown to be linked to an increased mortality and morbidity. However, obesity is often associated with modifications of physical activity level. Physical activity level itself affects the health status of the individual and thus may be a confounding variable in the obesity-mortality/morbidity relationship. Understanding the role of physical activity in the development of obesity-associated health hazards appears crucial for effective treatment of obesity and prevention of its complications. A large number of prospective studies have paid attention to the relationship between adiposity (i.e., degree of overweight/obesity) and mortality or morbidity. In the classic Framingham Heart Study (2), the degree of obesity predicted the incidence of cardiovascular disease. In the Harvard Alumni Health Study (3), men with the highest BMI (>26.0 kg/m2) had the highest risk of mortality. The Nurses Health Study (4) shows the lowest all-cause mortality and morbidity rates in subjects with the lowest BMI. The British Regional Heart Study (5) found an elevated all-cause mortality in men with BMI 30 kg/m2. A German study in obese subjects did show an elevated risk of all-cause mortality in obese subjects when compared with individuals with the lowest BMI, but, interestingly, did not find a difference in mortality rates between grossly obese (32 < BMI < 40 kg/m2) and overweight/moderately obese (25 < BMI < 32 kg/m2) patients (6). Abdominal fat distribution characterized by a higher waist-to-hip and waist-to-thigh ratio increases the risk of mortality not only among obese (BMI ≥30.0 kg/m2), but also among normal-weight (BMI 18.5–24.9 kg/m2) young and middle-aged adults (7). Measures of abdominal adiposity strongly and positively predict mortality, independent of BMI, among both white and black adults (8 …