The value of questioning
A few weeks ago, we shared a piece about why we don’t measure or particularly care about body fat percentage and body weight.
Today we are going to dive a little deeper into measuring and look at the efficacy of one of the most commonly used body fat percentage measures in commercial gyms - Bioelectric Impedance Analysis (BIA).
BIA is method at which body composition is measured by sending an electrical impulse through the body. Body fat causes greater resistance and slows the rate at which the electrical current travels and a reading is drawn from this.
Popular brands that use BIA include InBody Scanners or Tanita amongst several others.
What does the science say?
In a study done on bodybuilders, BIA had an error rate of up to 8% in both directions. So this means that a person that shows a reading of 20% body fat could be anywhere between 12% and 28%.
This study reviewed the use of BIA for large epidemiological studies. They concluded that BIA results are affected by factors such as the environment, ethnicity, phase of menstrual cycle and underlying medical conditions. The suggestion was if measurements were validated according to these factors the results would be more accurate however, if not considered BIA would not be suitable for large epidemiological studies.
InBody scanners claim to be 98% accurate when compared to a DEXA scan (the highest standard of body composition measure) but Dexa scanners themselves hold a level (5.5% to 9%) of variability.
Before we dive into the details, I’ll take you back a few years when we used BIA method to measure our clients.
We did two tests with 12 weeks between each test.
One of our clients did the first test, trained their but off for 6 weeks, hopped back on the scanner.
The results showed less than a KG of muscle mass increase, and an increase in body fat percentage by 2%.
Our client was heart broken and in tears as a result and felt all the hard work and good training had been a waste of time - not the way anyone wants a hard working and committed client to feel.
Although 8% or 5.5% is not something too significant to us normally, when it is to determine the success of your exercise and eating regime it means the world. Insignificant changes can make a person feel as if they have done insignificant work.
Likewise, what appears as a significant change may actually not be and nothing is worse than finding out you’ve been lured into a false sense of security.
So we encourage you to consider what your testing, consider why you’re testing it and then ask questions of the test themselves.
Results like these can influence adherence and a person's mental state so choose wisely.