Body Fat % FAQs

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1. How does the body fat device on the HealthZone work?

The FUTREX 6100 Body Fat Analyzer emits near-infrared light into the bicep muscle(mid-upper arm) at specific frequencies. Organic materials absorb light in unique portions of the spectrum. Body fat absorbs the light and lean body mass reflects the light. Due to this phenomenon, an estimation of distribution between body fat and lean body mass may be made.

The predicted body fat % is based on the reading from the FUTREX (which measures the body fat) as well as the person's gender, age, height and weight. That's why it's so important to measure your weight each time BEFORE you take your body fat % and make sure you enter a height measurement the first time you use the HealthZone.

2. Why does the HealthZone use the bicep to measure body fat?

Research was performed to determine that the bicep has a high correlation with overall body fat %. Tattoos or scar tissue on the biceps have been found at times to interfere with the device and cause inaccurate readings. This can be avoided by using a different area of the bicep or by using the opposite arm.

3. Do I need to do anything special before I use the HealthZone to measure body fat?

Unlike other methods, you can use the HealthZone at any time to measure your body fat; and no need to disrobe or use the restroom! However, please be considerate if you’ve worked up a sweat and make sure you use your towel to wipe your arm before taking your measurement.

4. How do body fat measurements compare across gender and age?

The body fat % norms for men and women are different as men generally have lower %s because of differences in genetic makeup. Therefore it is not possible to compare body fat %s between males and females. The norms for body fat are also age dependant, which means that you cannot compare a 20-year-old man with a 50-year-old man. When comparing body fat %s it is important that you only compare the same gender in the same age category.

The following table gives the norms for body fat % for various age groups for men and women:

Male	Excellent	Good	Acceptable	Fair	Poor
20-29	< 12	12 - 15	16 - 20	21 - 26	> 26
30-39	< 14	14 - 17	18 - 22	23 - 28	> 28
40-49	< 15	15 - 18	19 - 23	24 - 29	> 29
50-59	< 16	16 - 19	20 - 24	25 - 30	> 30
60 +	< 18	18 - 20	21 - 25	26 - 30	> 30
Female	Excellent	Good	Acceptable	Fair	Poor
20-29	< 18	18 - 19	20 - 24	25 - 32	> 32
30-39	< 19	19 - 22	23 - 27	28 - 33	> 33
40-49	< 21	21 - 23	24 - 28	29 - 34	> 34
50-59	< 23	23 - 25	26 - 30	31 - 36	> 36
60 +	< 24	24 - 26	27 - 31	32 - 38	>38

5. What's included in the body fat % calculation?
The following are taken into account and placed into an equation to calculate your body fat %:

FUTREX infra-red reading from your bicep;
age;
height;
gender and
weight.

That's why it's so important to measure your weight each time BEFORE you take your body fat % and make sure you enter a height measurement the first time you use the HealthZone.

6. Should I trust the reading?

The device has been proven to give repeatedly accurate readings if it's used correctly, but some of this is up to you! Remember to take the reading at the same place on the bicep each time. At the Grande ("big") HealthZones, you're able to adjust the lever height of the FUTREX device to make sure of this. It is very important that the device sits securely on your arm so that no light can slip in during the measurement.

The body fat % data from the HealthZone has been carefully studied and scrutinised by the Exercise Science and Sports Medicine (ESSM) department at the University of Cape Town (UCT) in South Africa and is proven to be accurate for gym go-ers. As we learn more about new technology and make exciting discoveries about the body, our products are constantly being updated to keep you in touch and on track… the simple, informative way!

7. How can you be skinny and still have a high body fat %?

Many people think that if you are skinny, you won't have a high body fat %. This is not necessarily true. Body fat does not only refer to the fat that is found beneath the skin (subcutaneous). We also have fat between our muscle fibres and protecting our organs. Skinny people can have lots of fat around their organs and amongst their muscle fibres, especially if they seldom exercise. This could give them a high body fat %, even though the fat's not visible.

8. How does the FUTREX compare to skin fold body fat measurement?

Although skin fold anthropometry is a simple, portable and low cost method of assessing body fat and is widely practiced, it has several limitations. It's also quite time consuming. Some other limitations include:

Accuracy of the test depends on who's taking the measurements.
There can be up to a 7% difference in the result when two equally trained people, using the same callipers, take the measurements using the same technique.
Calibration of the callipers affects accuracy and needs to be checked at least every 12 months.
Variations can also be caused by different skin fold techniques used by different assessors which decrease the accuracy of manual measurements. For example the assessor may not measure exactly the same part of the arm each time, which will decrease the accuracy of readings.
There are 7 validated equations that may be used to determine body fat % from skin folds.

9. Can you have too little body fat?

Excess body fat can be associated with many chronic diseases. By keeping an eye on your body fat, you can reduce your risk of these diseases. There's often far too much emphasis on weight rather than on body fat. It is not weight but fat that relates to hypertension, diabetes, gallbladder diseases, cancer and various other health problems. On the other hand, a very low body fat is not necessarily healthy either. Too low is not good, particularly for women. Studies show that women with low body fat %s are at a higher risk of developing osteoporosis and becoming infertile.