Mayo researchers have coined a new condition: normal weight obesity (NWO) also known as "skinny fat."
According to research from the Mayo Clinic, more than half of American adults thought to have normal body weight, as defined by their body mass index (BMI), have high body-fat percentages—greater than 20 percent for men and 30 percent for women—as well as heart and metabolic disturbances, which puts them at the same risk for developing coronary disease and diabetes as people who weigh much more.

The study looked at the body composition of 2,127 adults, equally divided between men and women, who had normal weight (BMI of between 18.5 and 24.9). After controlling for age, sex, and race, the researchers found that participants with normal weight obesity had significantly higher rates of some alterations in their blood chemistry that can adversely affect heart health, including:
  • Altered blood lipid profile, such as cholesterol
  • High levels of leptin, a hormone found in fat and other tissues
  • Higher rates of metabolic syndrome (a cluster of conditions, such as high blood pressure, elevated insulin levels and excess body fat around the waist, that increase risk for heart disease, stroke, and diabetes)
According to the Mayo researchers, their study findings suggest that rather than focusing on maintaining a "healthy weight" to reduce cardiovascular risk, the focus should shift to assessing percentage of body fat to get a more accurate reading on an individual's risk for heart disease.