Some people who have a healthy body mass index – meaning they are not overweight according to the usual height and weight criteria – may nevertheless have excess deep abdominal fat, a risk factor for heart disease and diabetes. A simple new body fat test for this so-called “visceral fat” could be on the way.

In a study of 196 lean and obese people, those with more visceral fat had elevated blood levels of a substance called serum retinol binding protein. A body fat blood test for this protein could be available within two years, says Timothy Graham, assistant professor of medicine at Beth Israel Deaconess Medical Center and Harvard Medical School.

This body fat test would also help identify those who carry extra pounds mainly in the form of subcutaneous fat, which poses fewer health risks than visceral fat. A waist-to-hip ratio greater than 0.8 is a sign of visceral fat in healthy-weight or slightly overweight women, Graham says.

Exercise is the best way to reduce it, he adds, and cutting back on carbohydrates may also help. [source: Allure]