What are the methods to measure body composition?

Method 1: Underwater weighing method. The most accurate test method is underwater weighing method. Because the specific gravity of human fat and non-fat components is different, the buoyancy in water is also different. Therefore, people think that the body weight measured by directly immersing the human body in water is less than that measured under normal conditions, and this difference is caused by the difference in the specific gravity of fat, so it can be used to calculate the body fat weight.

Method 2: bioelectrical impedance method. The bioelectrical impedance method is to apply a safe current to the subject's body and observe the current from his wrist to his ankle. Because the non-fat components (containing more water) in human tissues have smaller electrical impedance than fat tissues, when alternating current acts on human bodies, the current will mainly pass through non-fat tissues. Therefore, people with high fat content pass through the body more slowly than people with low fat content.