METHODS FOR ASSESING BODY FAT CONTENT
1) Skinfold Measurement
Body fat content can be estimated by measurement the thickness of fat folds that lie underneath the skin. Calipers are used to measure the thickness of fat folds. Preferably over several sites on the body. Body fat content is estimated by “plugging” the thicknesses into the appropriate formula.
Advantages
Calipers are relatively inexpensive. The procedure is painless if done correctly and can yield a good estimate of percent body fat.
Disadvantages
This technique is often performed by untrained people . Skin folds may be difficult to isolate in some individuals.
2) Bioelectrical impedance analysis(BIA)
Because fat is poor conductor of electricity, and water and muscles are good conductor, body fat content can be estimated by determining how quickly electrical current passes from the ankle to the wrist.
Advantages
The equipment required is portable and the test is easy to do and painless. The results are fairly accurate for people who are not at the extreme of weight- for – height
Disadvantages
Equipment maybe expensive; inferior equipment produce poor results. Hydration status and meal ingestion may affect electrical conductivity and produce inaccurate result as may inaccurate formula use to calculate body fat content from the test result.
3) Underwater weighing
The subject is first weighed on dry land. Next, the subject submerged in the water and exhales completely and subject’s weighs are measured. The less the person weighs under water compared to the weighs on dry land, the higher the percent of body fat.
Advantages
If undertaken correctly and appropriate formula are used in calculation, this technique gives an accurate value of percent body fat.
Disadvantages
The equipment are required are expensive and not easily moved. The test does not work for person who don’t swim or ill and disable in same way.
4) Magnetic Resonance Imaging (MRI)
By using the MRI, person body fat or muscle mass can be photographed from cross-sectional images obtained when the body exposed to a magnetic field. Fat can be determined based on volume of fat and muscle observed.
Advantages
Provide highly accurate assessment of fat and muscle mass
Disadvantages
Expensive. Largely used for research purposes.
5) Dual-Energy X-ray Absorpiotmetry (DEXA)
DEXA is based on the principle that various body tissues can be differentiated by the level of x-ray absorption. The measured is made by scanning the body by a small dose of x-ray and the body fat calculate based on the level of x-ray absorption.
Advantages
Provide highly accurate result. DEXA are safe and ‘friendly’. It can also be used to assess bone mineral content and lean tissue mass.
Disadvantages
DEXA machine is expensive and must be operated by trained and certified radiation technologists in many states.
6) Whole body air displacement
Individuals sit in an enclosed ‘cabin’ for 5 minutes while wearing a tight-fitting swim suit and cap. Computerized sensors determine body weight and the amount of air that is displaced by the body.
Advantages
Provides a quick, comfortable, automated and reasonable accurate way to assess body fat content. It is suitable for disable person, elderly and children.
Disadvantages
Results can be modified by drinking, eating and exercising before testing. In addition, a full bladder and failure to adhere to test procedures may lead to error in results.
Reference
1. Title: Nutrition . Auther: Paul Insel,R.Elaine Turner,Don Ross . Publisher :Sudbury,Mass:Jones and Bartlett, Year :2004
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