Posted on March 4th 2011 at 3:40pm
Body Mass Index (BMI) has been used for 200 years to calculate body fat, using a weight-to-height ratio. It has come under fire for not taking into account a number of factors, such as muscle mass. Now researchers at the University of Southern California have devised a system called the Body Adiposity Index (BAI), which uses height and hip measurements. This new method is outlined in the journal Obesity.
"The problem with BMI is it doesn't take into account that a person may be an athlete or a fitness expert," Dr. Michael Wolfe, chair of medicine at The MetroHealth System and professor of medicine at Case Western Reserve Medical Center, told AOL Health. "Someone with higher muscle mass will have a higher weight. BAI tells you more than just weight; it also tells you composition of weight."
The new research follows 1,733 Mexican-Americans and 223 African-Americans using the new BAI formula and compares how it correlates with their percent body fat as measured by DXA (dual-energy X-ray absorptiometry) scans, which are the gold standard of body fat measurements.
The formula is: BAI = (hip/height x the square root of height) minus 18.
For instance, a woman 5 feet 4 inches tall who weighs 127 with 37-inch hips would have a BMI of 21.7, a BAI of 27.8, and a DXA of 28.4% fat.
The study has not been replicated in other populations, and there are still some gaps in research: researchers found large differences in the BAI scores between very lean Mexican-Americans and very lean African-Americans.
Nonetheless, a new alternative body fat measure that could be better than the old method is always good news!