Comparing Body Fat Testing Methods

Body composition predicts the well-being of the human body. More importantly, fat composition is the key factor that affects your nutrients intake and diet plans. Therefore, several body-fat testing methods are here to help you regulate your diet plan and exercise routine. 


In addition to this, these testing methods are helping doctors in various disease diagnoses. For athletes, these tests are part of their routine checkups to ensure athleticism.


In this article, five popular and reliable testing methods are described with their pros and cons, so that you can choose the best for yourself. 

DXA scan or DEXA scan

Dual-energy X-ray Absorptiometry (DEXA) scanner is an advanced imaging technology that uses low-intensity X-ray radiations. 


The method is used to assess the total body mass, fat tissues,  bone mineral content (H.M.C), lean muscle mass, body fat percentage, and visceral fat in the body. The machine gives a detailed separate evaluation of different regions – arms, legs, trunk, android, and gynoid.


DEXA scan for bone density is recommended for females above 65 and males of age above 70. It helps athletes to diagnose the common condition known as Relative Energy Deficiency in Sport (RED-S).


For the procedure; remove all metal belonging, lie straight on your back, and maintain the motionless body posture. The arm-shaped apparatus runs above your whole body, scans every part of the body, and calculates body composition automatically. The scanning procedure takes about 30 minutes per person. 


  • Has high precision and accuracy in regional fat estimation

  • Efficient to determine minor risks in bones

  • Has multi-fold purpose 

  • Speedy and painless process 

  • Need Minimum manpower

  • Gives Detail information sheet 


  • Even the slightest exposure to X-ray is harmful

  • High priced apparatus, therefore not accessible to everyone

  • Not appropriate for pregnant women and people with pacemakers

  • Have severe side effects 

Hydrostatic weighing (dunk tank)

Hydrostatic weighing is an old-school yet gold standard method to weigh the density of the body; from which you can measure body fat percentage. The apparatus consists of a huge stainless steel tank, hanging swing, and attached scale. Cylindrical or rectangular tanks are used for underwater weighing tests.


The person must exhale all lung air before dipping in the tank completely. Wearing a lightweight dress is compulsory.


The process is repeated twice or thrice to get the accurate average measurement. The attendant calculates the body fat percentage by comparing body density in the land and water. The whole process takes 10-15 minutes.


  • High accuracy

  • Unlike Dexa scan and bioelectrical impedance, it has no side effects

  • Less time consuming


  • Expensive to install as needing more space

  • Calculation is manual 

  • People having hydrophobic or respiratory ailments 

  • If air is not exhaled properly, make the calculation faulty

  • Regional assessment is not possible

Air displacement plethysmography (bod pod)

Bod Pod is a computer-operated egg-shaped apparatus that efficiently estimates fat percentage, lean body mass, resting metabolic rate, and total energy expenditure in the body. The machine is programmed to use Boyle’s law to infer calculations. 


Clothes add erroneous values in calculations. Therefore compression shorts for men and compression shorts and jog bras for women are recommended. Compress cap is a must-wear during the process. 


The calculations are taken in two steps: In the first step, calculate mass and volume by sitting normally in the machine. To take a second measurement, open the door slightly and then close it. The machine calculates the average density and fat percentage.



  • It is convenient for people who cannot face the water. 10 minutes

  • Device calculate automatically replacing the need for manual calculation

  •  Less burdensome


  • The apparatus is expensive to buy

  • Professional training is required

  • have same inaccuracy as hydrostatic

Bioelectrical Impedance

Bioelectrical Impedance is the easiest method to estimate body fat percentage. This test assesses body fat in two ways; head-to-foot and foot-to-foot. 


The types of equipment involved in head-to-foot fat analysis are; BIA device, electrodes, wires with clips, and exam table. 


While foot-to-foot body fat procedure requires a BIA device, weight scale, and height scale. In foot-to-foot analysis height, gender, and weight factors determine your body fat percent.


For the procedure, lie the subject on his back, adhere the electrodes on the skin – one on the wrist and one on the knuckle of the right hand, one on the ankle, and one on the knuckles of the right foot. Connect these electrodes with clips and wires. Low voltage current is passed and the calculations can be seen on the device. The less the resistance is, low the fat composition in the body and vice versa.


  • Gives information about muscle mass and body fat spontaneously

  • Cost-effective and portable 


  • Water percentage affects the accuracy

  • Not suitable in conditions of pregnancy, heart disease, obesity, and malnutrition

Calipers skinfold measurements

Caliper Skinfold test is widely used to measure the subcutaneous fat composition in the body. As you know,  subcutaneous fat is present under the skin and is visible. Therefore, the thickness of the skinfold from different regions is measured with the help of a caliper to assess the fat composition. 


The main regions where the skinfold can be measured are the biceps, triceps, abdominal region, under the shoulder blade, and on the iliac bone.


For the procedure, the skinfold is pinched vertically from the particular region by taking the fat and leaving the muscles behind. Caliper claws are used horizontally to grab the skinfold.



  • Apparatus is cheap and portable

  • Test cost is minimal

  • Can be used by anyone after basic training


  • Time taking process

  • Accuracy depends upon the skill of the person

  • Measurement is limited to visible subcutaneous fat tissues. Therefore cannot measure the aggregate fat composition of the body

  • Unreliable for old age people because of their loose skin tissues

  • Least accurate for overweight and skinny people

  • Difficult to differentiate muscle from fat so miscalculation occurs.


Each method has its advantages and limitations. Skinfold calipers and hydrostatic weighing methods are both cost-effective tests but the latter is more accurate. Air displacement plethysmography and hydrostatic weighing are each other’s substitutes, but the latter is cheap. Bioelectric impedance and Skinfold caliper apparatuses both are convenient, handy, and easy to carry.