F at is a natural part of the body, but in today’s consumerist society, which encourages binge-watching, binge-eating, binge-drinking, and overworking to support all these, the risk of obesity and metabolic diseases can no longer be ignored. To stay healthy, it is vital to know where you position yourself from what is considered normal so you can take the right measures on time and avoid cardiovascular complications or diabetes.
In this context, specialists have created a series of methods and gadgets that can help you calculate your weight-to-height ratio, your waist-to-height ratio, or even your body fat ratio. One of the most prevalent for a few years now is Bioelectrical Impedance Analysis, which, conferring to the latest body fat scale reviews, can be used to offer a rough image of your body structure while remaining completely non-invasive.
In this article, we explain the mechanism behind body fat monitors and analyze the advantages and disadvantages brought by BIA. We also compare BIA with the BMI to see if the new technology is more effective in predicting obesity.
When using a body fat analyzer, the first rule is that you need to stand shoeless on the glass surface. This is because it uses a low electrical stream to establish the proportions of fat, water, muscle, and bone in your body. BIA is based on the rule that dissimilar types of tissues in the body respond differently to low voltage. For example, the voltage travels faster through water, bone, and muscle but struggles to cross the dense fat tissue. After measuring the voltage’s response, the scale finds total body water. Then, based on the assumption that a higher water percentage means a lower fat ratio, it uses a series of algorithms to assess the fat-free mass in the body. The fat proportion is the last to be computed as a difference between total body weight and fat-free body weight.
Depending on the model, the scores are displayed either on a screen on the device or transmitted to your phone. More advanced products come with apps that can create graphs so you can better visualize your evolution. The number of variables calculated can also differ, some models offering only the 4 more important, while others being able to deliver you a more complete analysis that can include up to 17 parameters or more. According to this study, 4-electrode models are more reliable and should be preferred for both individual and public use.
In general, BIA shouldn’t be used for clinical assessments, as studies have proved that it only delivers non-specific results. More specifically, it is pretty good at approximating how much fat you have in your body but not that good at telling you where you have it. Since physicians are interested mostly to know if the fat is located around your abdominal area, as this can help them assess the risk for most of the metabolic diseases, the body fat ratio doesn’t really help them unless a supplementary analysis method is employed, DXA being recognized as the most precise.
Another factor that weighs a lot when evaluating a scale’s precision is the formulas it uses to compute the ratios, as some brands choose to go with simplified options that result in lower accuracy.
It works well if the analyzer has an Athlete mode. When this option is activated, the device employs a different series of formulas that were adapted to reflect the lifestyle of a highly active person. More precisely, it compensates with more muscle mass and reduces the fat percentage. This can help athletes understand where they stand among people from their own category and estimate if they have healthy fat and muscle ratios. The technique is more consistent than the Body Mass Index, which can easily categorize an athlete as obese.
This technology is considered safe, as the voltage that goes through the body is extremely low. Nevertheless, there are still some categories that are advised to avoid using BIA as more clinical trials need to be performed:
The fat ratio differs depending on age and sex and reflects in a good proportion the BMI value. Check the following tables to see if yours is in the healthy range:
Age Group |
Dangerously Low |
Great |
Good |
Acceptable |
Poor |
Dangerously High |
---|---|---|---|---|---|---|
20-29 years |
<14% |
14 to 16.5% |
16.6 to 19.4% |
19.5 to 22.7% |
22.8 to 27.1% |
>27.2% |
30-39 years |
<14% |
14 to 17.4% |
17.5 to 20.8% |
20.9 to 24.6% |
24.7 to 29.2% |
>29.2% |
40-49 years |
<14% |
14 to 19.8% |
19.9 to 23.8% |
23.9 to 27.6% |
27.7 to 31.9% |
>31.3% |
50-59 years |
<14% |
14 to 22.5% |
22.6 to 27% |
27.1 to 30.4% |
30.5 to 34.5% |
>34.6% |
Over 60 years |
<14% |
14 to 23.2% |
23.3 to 27.9% |
28 to 31.3% |
31.4 to 35.4% |
>35.5% |
Age Group |
Dangerously Low |
Great |
Good |
Acceptable |
Poor |
Dangerously High |
---|---|---|---|---|---|---|
20-29 years |
<8% |
8 to 10.5% |
10.6 to 14.8% |
14.9 to 18.6% |
18.7 to 23.1% |
>23.2% |
30-39 years |
<8% |
8 to 14.5% |
14.6 to 18.2% |
18.3 to 21.3% |
21.4 to 24.9% |
>25% |
40-49 years |
<8% |
8 to 17.4 % |
17.5 to 20.6% |
20.7 to 23.4% |
23.5 to 26.6% |
>26.7% |
50-59 years |
<8% |
8 to 19.1% |
19.2 to 22.1% |
22.2 to 24.6% |
24.7 to 27.8% |
>27.9% |
Over 60 years |
<8% |
8 to 19.7% |
19.8 to 22.6% |
22.7 to 25.2% |
25.3 to 28.4% |
>28.5% |
Several studies have shown in the past years that BIA is more truthful in establishing if an individual is obese than the traditional BMI, as this technology can assess the proportion of fat and muscles and even calculate them correctly for athletes. Since it is non-invasive, it is thought to be a good way to estimate if a person has a healthy body composition. However, it does have its limits like, for instance, the fact that it cannot show where the fat is deposited or the lack of precision some residential scales present. At this moment, it can be successfully used along with the BMI to identify possible body fat ratio trends that may represent a risk for developing further cardiac diseases.