Body fat percentage is the proportion of body fat weight to total weight. If the weight of fat exceeds the standard, people will look fat and may cause health problems. It is generally believed that the normal range of adult body fat rate should be: male 15% to 18%, female 20% to 25%. However, it is clearly pointed out in the Guide to Physical Fitness Testing and Evaluation issued by the National Physical Fitness Association (NSCA) that there is no recognized standard for measuring body fat rate because of its complexity.

It is true that body fat percentage can be calculated by some formulas, but it is hardly used by the public and is not practical. Let's take a look at two most practical methods for measuring body fat percentage.

In fact, this method of measuring body fat percentage is the most common body fat tester in the gym and the body fat scale at home, and the body fat percentage value is automatically calculated through the impedance measured by micro-current.

Many people complain that the value of body fat rate measured by this method changes greatly and is not accurate. This is precisely the shortcoming of this measurement method. If you want to measure the body fat rate more accurately by this method, you must control many measuring factors, such as ensuring that the size and intensity of each contact between your hands or feet and the metal sensor are as consistent as possible, and controlling the water in your body (too much urine will also affect it, so you should empty it). Therefore, when using this method to measure body fat percentage, we should try to keep the same measurement conditions every time, including not changing different body fat testers or scales.

The measurer can also use the method of periodic measurement (such as once a week) to judge the reliability of each measurement data by observing the continuous trend of body fat percentage. Some studies believe that the BIA method tends to overestimate the body fat rate of thin people and underestimate the body fat rate of fat people.

According to the method of 1, even if the measured body fat rate is accurate, it can only reflect the proportion of total fat, but not the distribution of fat, which is highly related to potential health risks. At the same body fat rate, people with big bellies and slender limbs (typically "general bellies" and "beer bellies") are more dangerous and more prone to metabolic and cardiovascular diseases than people with even fat. Therefore, it is recommended to pay attention to the following two indicators:

The measurement of waist circumference is very simple, just a tape measure. According to the definition of the World Health Organization (WHO), central obesity (abdominal obesity) is defined as the waist circumference of men exceeding 102cm and that of women exceeding 88cm.

Waist-hip ratio, that is, the ratio of waist circumference to hip circumference, is measured with a tape measure. The definition of WHO is that men should not exceed 1.0 and women should not exceed 0.9, otherwise it is also central obesity.

Generally speaking, controlling the waist circumference also controls the body fat rate. However, it is almost impossible to control waist circumference without diet and exercise, and the older you get, the more difficult it is.

In addition to the above two methods, there are actually many methods to measure body fat rate, but they are not suitable for ordinary people. For example:

Leather folding thickness measurement. This method is very simple and can be measured with plastic calipers. However, there are requirements for the position, technology and strength of surveyors, and it is necessary to train surveyors in advance. From the subjects, in addition to inconvenience, there are privacy protection and physical discomfort (sweating in summer and too cold in winter).

Computed tomography (CT) and magnetic resonance imaging (MRI). Both methods can measure the body fat rate very accurately, but the equipment cost is too high, and the measurement process is time-consuming and expensive, so it can't be popularized.

In addition, there are some methods to measure body fat percentage, but they can't be widely used because of the big error, high measurement conditions, business training, special equipment or site requirements.

For the general fitness and weight loss crowd, it is enough to test whether the current exercise and diet plan is effective by mastering the body fat rate through the body fat scale and then grasping the distribution of the body fat rate through the waist circumference and waist-hip ratio. Pursuing a highly accurate body fat percentage value has no practical significance for the general public.