Skinfold testing is based on the fact that most of the body fat is stored directly beneath your skin. The skinfold test is performed with a simple machine called a skinfold caliper. The jaws of the caliper pinch a fold of skin and fat and measure the thickness of the fat fold in millimeters. Using the calipers, skinfolds measurements are taken at different sites around the body and then the measurements are added up.
The sum of the skinfolds is then looked up on a body fat estimate chart that is available with the calipers. A proficient tester can produce a body fat measurement with accuracy very close to benchmark standards. Most importantly, skinfold testing is extremely practical and lot more simpler than many of the measurement techniques. However, the accuracy of the measurements may vary from tester to tester. Other Methods
There are many other methods used to measure body fat percentage, including Total Body Potassium, Dual-Energy X-Ray Absorptiometry (DEXA), Total Body Electrical Conductivity (TOBEC), Whole-Body Air-Displacement Plethysmography, Magnetic Resonance Imaging (MRI) and Computed Tomography (CT scan). While some of these modern methods may be incredibly reliable and useful in the laboratory, none of these methods is practical at least for personal use for a weight loss program.Now you understand the importance of body fat versus body weight and you understand that height and weight and Body Mass Index (BMI) tables are worthless. It is also clear that losing weight is not of prime importance, but losing fat is.