Not Overweight? You May Still Be 'Fat'

Jan. 12, 2007 -- Women who aren't overweight but still have a high percentage of body fat may have more inflammation in their bodies, an Italian study shows.

Researchers looked at 60 healthy Italian women aged 20-35 living in Rome.

Twenty of the women were overweight or obese based on their BMI (body mass index), which relates height to weight.

Another 20 had a normal BMI, but their body fat was greater than 30%, based on head-to-toe body scans using dual-energy X-ray absorptiometry (DEXA).

The researchers call these women "normal-weight obese" because of their high percentage of fat.

The remaining 20 women had a normal BMI and body fat less than 30%, based on the DEXA scans.

Measuring Inflammation

When researchers analyzed blood samples from the women, they found those who were overweight or obese had the highest levels of inflammatory chemicals, LDL ("bad") cholesterol, and triglycerides (a type of blood fat).

But the "normal-weight obese" women also had higher levels of inflammatory chemicals than those with both a normal BMI and lower body fat.

Based on the findings, the normal-weight women with high body fat "were in an early inflammatory state," the researchers write.

Body fat may release inflammatory chemicals, note researchers Antonino De Lorenzo, MD, and colleagues, who didn't test that theory in this study. De Lorenzo works at Rome's University of Tor Vergata.

Chronically high levels of inflammation have been associated with a host of health problems, including heart disease and arthritis.

Both groups of women with normal BMI had similar levels of cholesterol and other blood fats, regardless of their body fat.

All the women had normal blood pressure. None had heart disease and none smoked, abused alcohol, or used birth control.

Study's Limits

The women weren't followed over time, so it's not clear if they had health problems later in life.

The data also don't include the women's diet and exercise habits, or whether genetics affected their amount of body fat.

But the study does show that some women with normal BMI may still have a high percentage of body fat and elevated levels of inflammatory chemicals.

It appears in the American Journal of Clinical Nutrition's January issue.