Blacks tend to carry around less of an unhealthy type of abdominal fat than whites, even though they suffer more from obesity-linked illness

The new finding suggests that body-mass index (BMI) guidelines may need to be tailored to specific racial groups to better reflect risk, experts say. Adipose (fat) tissue is found throughout the body. Subcutaneous adipose tissue is found just under the skin, while visceral adipose tissue is found in the abdominal cavity around the organs. Fat settling around the organs has been linked to development of obesity-related diseases such as cardiovascular disease and type 2 diabetes. But you can't tell just by looking at someone how much visceral fat someone has. Even a pot belly won't tell you for sure because visceral fat is deep within the body cavity. In the study, researchers used computer tomography (CT scans) and dual- energy X-ray absorptiometry (DXA) to measure visceral fat in about 1,400 white men and women and 570 black men and women aged 18 to 84. Participants' height, weight, BMI and total body fat composition were also measured. At a given body fat percentage, black men and women had lower visceral fat than white men and women. Conversely, blacks also tended to have higher subcutaneous fat than whites. Researchers controlled for age and smoking status, among other variables. Despite the tendency to have less visceral fat, black Americans are still at higher risk of dying from obesity-related diseases such as diabetes and cardiovascular disease. One explanation for this is that blacks have higher overall obesity rates overall. About 31% of white adults and 45% of black adults are obese, according to the study. The findings bring up the issue of whether the "one-size-fits-all" BMI guidelines apply equally to all races. Previous research has suggested there may be racial variations in what constitutes a healthy BMI. Diabetes risk for Asians start to rise at a BMI of about 23, for example. An optimal BMI for blacks may also vary somewhat.