Is excess body fat obesity? How does a body fat scale know our fat content?

When a person decides to lose weight, the first thing he or she may do is to buy a body fat scale.

Because human body weight is composed of muscles, bones, organs, fat, etc., having a body fat scale can help us better understand our body fat percentage, so as to make appropriate adjustments to our weight loss plan in real time. However, from the outside, the body fat scale is no different from an ordinary weight scale. How does it know how much fat we have? Is the body fat percentage measured by the body fat scale accurate? The so-called body fat percentage is the proportion of fat tissue weight in the total body weight. Before the popularity of body fat scales, if a person wanted to know his body fat percentage, he had to go to a hospital or other professional institution for testing, and there were roughly three types of methods.

Traditional methods for detecting body fat percentage include underwater weighing method, ADP method and ultrasonic detection method.

We know that there is a big difference between the density of fat tissue and muscle tissue, so according to Archimedes' principle, we only need to measure a person's underwater weight and land weight, and then know the density of water to accurately calculate a person's body fat percentage. This is the underwater weight measurement method. The underwater weight measurement method is a classic method for measuring body fat percentage, but it is more complicated to operate. The person being measured needs to be completely submerged in water and remain still in order to obtain accurate results.

ADP method, the full name is "air displacement volume scanning method".

This method is to place a person in a special instrument, measure the volume of the human body in the instrument, and calculate the body fat ratio. The ultrasonic detection method is even more convenient. By using ultrasound to directly detect the fat content in the human body, accurate body fat percentage data can be obtained. Whether it is underwater weighing, ADP or ultrasonic detection, it can accurately measure a person's body fat percentage, but we have no way to operate these measurement methods ourselves. We must go to a professional organization and use professional equipment to complete the measurement.

In order to enable everyone to easily measure their body fat percentage at home, a new measurement method has emerged. This method is called "bioelectrical impedance method", which is used by body fat scales.

The human body is conductive, but the conductivity of different tissues in the human body is significantly different. For example, the conductivity of fat is very poor, with a high resistivity. Relatively speaking, muscle contains more water, so it has good conductivity and low resistivity. The bioimpedance method uses this difference in conductivity to measure the body fat percentage of the human body.

Body fat scales release microcurrents that flow through the body's fat, muscles, bones and organs.

In different human tissues, these microcurrents will encounter different resistances, so by simply measuring the rate and time at which these microcurrents pass through the human body, the difference in resistivity of various parts of the human body can be determined, thereby calculating the proportion of fat and muscle in the body. From the principle of measuring body fat percentage with a body fat scale, we can see that this measurement is impossible to be accurate, because there are many factors that may interfere with this measurement. In order to eliminate interference as much as possible, be sure to take off your shoes and socks when using a body fat scale. Even so, the body fat percentage we ultimately obtain is still just an estimate.

The body fat percentage measured using a body fat scale is an estimate, and sometimes this estimate can be very different from the actual situation.

But this does not mean that body fat scales are useless. When using body fat scales, we should not pay too much attention to the specific body fat percentage value, because this data is not very meaningful for reference. We should focus on the changes in body fat percentage. Although the measured body fat percentage value is not very accurate, the changes in body fat percentage value can well reflect our weight loss and fitness effects. By understanding the changes in body fat percentage value, we can make reasonable adjustments to our weight loss and fitness plan.