Understanding Body Composition

A body composition measurement can serve as an indicator of our overall health and wellbeing. This measurement refers to the distribution of fat, muscle, bone and other tissues that make up the body. Typically, body composition is divided into two categories: fat mass (stored fat in the body) and non-fat mass (muscles, bones, and organs). While checking our weight on a scale may be beneficial, a scale cannot tell us how our weight is distributed through our body, which is why estimating our body composition may be beneficial. Research shows that higher ratios of fat to non-fat mass increases risk for premature death and chronic disease.

There are several methods available to estimate body composition, each with varying levels of accuracy, convenience, and cost. Below, we’ll explore some of the most common options.

Skinfold Measurements

Special tools called skinfold calipers are used to measure subcutaneous fat at predetermined sites across the body. These measurements are then put into an assessment equation to estimate body composition. While this is an accurate and low-cost method, there is risk of user error while taking the measurements.

Bioimpedance Analysis (BIA)

This method uses a device that is similar to a typical scale. A user stands on the scale with bare feet while a low-energy electrical current passes through the body. Because muscle contains more water than fat, it will conduct the energy current better than fat. The BIA tool can then estimate body composition based on how the electrical energy moves through the body. This method is fairly accurate but is dependent on the individuals hydration level. These tools can be commonly found online in the $100 price range making them a relatively accurate option for home use.

Dual Energy X-Ray Absorptiometry (DEXA)

With a DEXA scan, low energy X-rays are used to measure the weight of bone, muscle, and body fat. While highly accurate, these tools are often found only in medical facilities making them difficult to access.

Hydrostatic Weighing

This method involves the user being fully submerged in water while sitting on a scale to measure the water displacement. Fat floats while lean tissues sink in water thus only measuring lean body mass. This method has been considered the gold standard, but it quite uncomfortable, high cost, and only accessible in university facilities.

BodPod

A Bodpod is a relatively new method for body composition measurement. The user sits in a chamber with a fully sealed door while the machine creates gradual changes in pressure to measure volume. The measure of air displacement is then able to calculate the users body composition. A new emerging gold standard for accuracy and far more comfortable than Hydrostatic weighing, but expensive, and often inaccessible unless in a lab setting.

Why is Body Composition Important to Health?

Excess fat (especially visceral fat) and low muscle mass strongly predicts increased risk for health concerns such as Type 2 Diabetes, cardiovascular diseases, hypertension, certain cancers, metabolic syndrome, fatty liver disease, osteoporosis, sarcopenia (muscle loss), and sleep apnea. Working toward a healthy body composition supports overall health and longevity. It also shows true fitness progress beyond just the number on the scale.

By Jenna Heitshusen, CHC, CPT, CGFI, Health Coach

Photo: ©iStock.com/Kobus Louw