Not All Belly Fat Is Bad for the Heart

 Where a person stores body fat may be more important for heart disease risk than how big they are, a new study shows.

Doctors have long wondered why some obese people look metabolically normal; that is, they have normal cholesterol, blood sugar, and insulin levels, while others are insulin resistant, have high blood sugar, and high cholesterol -- a profile that puts them at high risk of heart disease and type 2 diabetes.

Visceral fat, or fat that’s stored around the internal organs, has been thought to play a role in that difference. Waist size is a rough measure for the amount of visceral fat a person has.

But newer studies have suggested that visceral fat may not deserve all the blame.

“During the last 10 years, with advances in imaging techniques, we have been able to measure the fat content of non-adipose tissues like skeletal muscles and liver,” says Faidon Magkos, PhD, a research assistant professor of medicine in the department of nutrition at Washington University in St. Louis.

“And there’s an accumulating body of evidence over the last decade that shows that it really isn’t visceral fat that’s associated with dyslipidemia or insulin resistance or other cardiometabolic risk factors, but instead, it’s fat deposited in skeletal muscle and liver,” says Magkos, who studies metabolism but was not involved in the current research.