What’s the correct way of calculating body fat percentage and lean mass?
The previous gold standard for body composition analysis has been hydrostatic weighing. Short of a university research lab, you may have trouble locating such a dunk tank. A dual energy x-ray absorptiometry (DEXA) scan is a higher tech method available in medical care settings, since they primarily use them for bone density status. A Bod Pod device provides reliable results, though it’s difficult to find one of these space-age egg-shaped chambers. In general, these methods basically use the difference in density of body tissues to determine how much of each you have. They also carry a price tag.
So what does that leave for you that’s readily available? Skinfold thickness testing using digital calipers may be an option if there is a trained individual performing the measurements with good equipment. It determines subcutaneous fat to predict overall body fat. The best simple, fast and inexpensive method is an electronic bioelectrical impedance analysis (BIA) scale with integrated upper body measurement. Such segmental devices get an overall picture by looking at hydration status of all 4 quadrants & torso of the body. As if a step-on BIA scale and a hand held analyzer had an offspring. The small electrical signal passes through muscle and fat differently based on their water content.
You don’t have to calculate body fat % or lean mass as the above methods have equations built into the software. In the case of skinfold thickness with traditional calipers, the most accurate formula uses six or more body measurements whose sum is usually available in a table format for conversion into body fat.
– Debbie J., MS, RD
This article should not replace any exercise program or restrictions, any dietary supplements or restrictions, or any other medical recommendations from your primary care physician. Before starting any exercise program or diet, make sure it is approved by your doctor.
Some questions have been edited for length and/or clarity.