What exactly is the difference between belly fat and thigh fat, for instance?
"Visceral [belly] fat has been found to be more metabolically active," Dr. Francisco Lopez-Jimenez, the study's lead investigator and director of Mayo's Cardiometabolic Program, explained in the news release. "It produces more changes in cholesterol, blood pressure and blood sugar. However, people who have fat mostly in other locations in the body, specifically the legs and buttocks, don't show this increased risk."
Doctors should look beyond BMI in assessing patients' health risks and advise those with a large waist or a high waist-to-hip ratio to lose weight, even if they have normal BMIs, the study authors said. A BMI of between 18.5 and 25 is considered normal; between 25 and 29.9 is overweight; and a BMI of 30 or more is obese.
"All it takes is a tape measure and one minute of a physician's time to measure the perimeter of a patient's waist and hip," Coutinho said.
The study participants came from the United States, Denmark, France and Korea, and that diversity gives real-world applicability to the findings, Coutinho said.