Is the Hand-Held Body Fat Machine Accurate? Learn What Bioelectrical Impedance Analysis Is And What it Means To You

Bioelectrical Impedance Analysis: What Is the Body Fat Analyzer?

There are several instruments that are commonly used to measure human body composition. They vary in cost, accuracy, and required level of skill needed for operation.

One of the most frequently used body fat analyzers is a device that measures body composition through bioelectrical impedance analysis or BIA. It is more commonly known as the body fat analyzer or body fat machine.

The hand-held body fat analyzer sends an electrical current through the body and measures the amount of resistance to the current. The electrical current flows more or less easily through the body depending on how much fat or lean mass (muscle, bone, organs) is there. By measuring how the electrical current flows through the body, the test can estimate the percent of fat in the body.

This explanation is simplistic and serves to clarify how the machine works in theory. The more important issue is how well the machine works in practice.

Is It Right for Everyone?

The body fat analyzer’s results can be skewed by several factors and should not be used in all populations. This is because it has to factor in certain assumptions about the person being tested and use those assumptions in the equations that are programmed. Usually, the only information entered are things like height, weight, gender, age. The further away the person’s conditions are from the assumptions, the more skewed the results will be.

The body fat analyzer is frequently used in the fitness setting because it’s relatively inexpensive as compared to other body composition tests. It’s also popular because it requires little skill and preparation to obtain an accurate measurement. This is where the problem lies.

Great Tools Can be Used the Wrong Way

The manufacturer’s instructions always accompany body fat machines, but like other technical equipment, these instructions are often ignored or forgotten. Some body fat analyzers advise that because of how body composition changes with age, the machine should not be used to measure body fat in people over a certain age.

This is an issue because the other common setting the body fat analyzer is used in is the community health event or health fair. Many of the people in attendance at these health fairs are seniors. Consequently, there is another population of people receiving inaccurate body composition measurements from a body fat analyzer that would otherwise be useful and reliable.

There are also many other factors that can affect the accuracy of test results. Among these factors are level of hydration, swelling, environment, and recent alcohol consumption. The best advice for anyone that uses the BIA or body fat analyzer is to read, understand, and follow the manufacturers recommendations before using it. Ursula G. Kyle provides a more detailed look into BIA in her Clinical Nutrition journal article, "Bioelectrical Impedance Analysis-part II: Utilization in Clinical Practice".


Bioelectrical Impedance Analysis-part II: Utilization in Clinical Practice. Ursula G. Kyle.