You can be fat AND fit, researchers say
"It is well known that obesity is linked to a large number of chronic diseases such as cardiovascular problems and cancer," lead study author Dr. Francisco Ortega said in a statement. "However, there appears to be a sub-set of obese people who seem to be protected from obesity-related metabolic complications."
The study: Researchers analyzed data from 43,265 participants in the Aerobics Center Longitudinal Study, which was done between 1979 and 2003. The participants' body fat percentages were determined using hydrostatic weighing (submersion in water) or skinfold measures, and their fitness levels were tested on a treadmill. Using these criteria, 29.7% of the study participants were labeled obese. Of the obese, nearly half were considered "metabolically healthy." All of the participants were followed until 2003; 1,779 died during that time period.
What's metabolically healthy mean?: Your metabolic health is determined by several factors: High blood pressure, high triglycerides, low HDL - or good - cholesterol and high fasting glucose levels. For this study, a participant was considered metabolically healthy if they displayed zero or only one of the above symptoms. Ortega and his colleagues use several terms to describe the study participants who were obese but metabolically healthy. They call it "uncomplicated obesity" or "metabolically benign obesity." Basically that means the obese individuals saw few negative health effects of their extra weight.
The results: The researchers found that the metabolically healthy but obese participants had a 38% lower risk of dying than their metabolically unhealthy peers. There was also no risk difference between the metabolically healthy obese and the metabolically healthy normal weight participants.
COMMENT: This study should help us focus our attention on obese persons who are at low risk for cardiovascular disease. It should also help us in counseling overweight and obese patients about obtaining cardiovascular fitness. To me the study suggests that a healthy approach to such patients should combine cardiovascular risk factor assessment and advice regarding obtaining cardiovascular fitness as well as encouraging weight loss.