Whether a person is fat or not depends on the "roundness index", which is more reliable than BMI

Whether a person is fat or not depends on the "roundness index", which is more reliable than BMI

People who are concerned about their health have generally heard of the BMI index. Many people will use the BMI index to test whether their current weight is overweight. As everyone knows, this BMI index is not accurate and may mislead you into eating more body fat. Today we will share another index. Referring to this index may make your body healthier!

The classic BMI index may not be easy to use

BMI (body mass index) is what we often call body mass index. It is calculated by dividing weight (kilograms) by the square of height (meters). Because it is easy to understand and easy to operate, it has become the most commonly used indicator to evaluate whether your current weight is normal. It is also an important indicator for screening obesity in large samples.

BMI index rating scale

However, because it relies on the two values ​​of height and weight, it does not take into account the impact of different body compositions of the people being measured, causing the BMI results to be inconsistent with the facts. In other words, two people with the same BMI index are likely to have huge differences in health status.

For example, for bodybuilders, their body fat percentage is very low and their muscle content is high, but the weight of muscle is greater than the weight of fat. This will lead to a high BMI index for these bodybuilders, and they can easily reach the level of overweight or even obesity, which is contrary to the original intention of the BMI index.

There is also a group of people who are defined by the BMI index as having a normal or even low weight. They look thin from a distance, but have an obvious potbelly hanging on their slender torsos when viewed from the side. Their body composition is measured to have excessive visceral fat. This type of people are the "thin and high-fat people", and they are a fish that cannot be measured by the BMI index.

Another limitation of the BMI index is that gender and age will have a significant impact on it. Therefore, in the process of national physical fitness monitoring, in order to more accurately describe the weight and health status of this age group, the BMI index classification standard will fluctuate based on gender and age.

An index that better describes obesity: BRI index

Since the BMI index is unreliable, are there any other indicators that are both accurate and easy to calculate? There really is one, and that is the recently popular BRI index.

The BRI (body roundness index) index is called body roundness index and is used to evaluate whether the body's visceral fat content exceeds the standard. This index is calculated based on height and waist circumference. The higher the value, the more obvious the accumulation of visceral fat, and the higher the incidence of obesity, metabolic syndrome and other diseases.

BRI index calculation formula

Through this indicator, those "thin and fat people" can be screened out and health management intervention can be provided in a timely manner. Compared with the BMI index, the biggest difference between the BRI index and the BRI index is that it does not take weight into account, but directly measures waist circumference, which effectively blocks those with large muscles and bodybuilders, and can also promptly catch those with excessive visceral fat. Especially for the elderly, the BRI index can more accurately assess their health status.

Excessive visceral fat is a major pain for modern sedentary people. Excessive visceral fat will lead to an increased risk of chronic diseases such as coronary heart disease, type 2 diabetes, and metabolic diseases. People with excessive visceral fat are also called central obesity, which is characterized by an obesity state in which the fat appears to be "normal" but the actual fat is distributed in the abdominal viscera. The overall appearance is "normal" but the waist circumference increases.

According to my country's population standards, central obesity can be diagnosed when the waist circumference is ≥90cm for men and ≥85cm for women; or by accurately measuring the visceral fat area using CT or MRI and other equipment, central obesity can be diagnosed if it is ≥80cm². Therefore, to determine whether you are fat or not, it is more reliable to measure your waist circumference and calculate the BRI index.

How to self-test the BRI index?

Since waist circumference data is so important, waist circumference measurement must be as accurate as possible. The standard measurement method for waist circumference is as follows:

1. The person being measured should wear light clothing, stand in an upright posture, keep the feet 25 to 30cm apart naturally, distribute the weight evenly to both legs, maintain steady breathing, and avoid taking measurements while inhaling.

2. Use a soft ruler with no elasticity and a minimum scale of 1 mm. At the midpoint of the line connecting the highest point of the iliac crest and the lower edge of the 12th rib, measure around the abdomen in the horizontal direction. Keep all parts of the ruler in a horizontal position and close to the skin without compressing it.

3. During measurement, the person being measured should keep their abdomen relaxed and not tightened.

4. The measurement value should be accurate to 1mm.

At present, there is no completely unified standard for the normal range of BRI. Research generally believes that people with a BRI of around 4.5 to 5.5 are relatively healthy and have a relatively low risk of death.

People with BRI less than 3.4 may have malnutrition, muscle atrophy or lack of activity, and all-cause mortality may increase by 25%. For people with a BRI of 6.9 and above, all-cause mortality may increase by 49%, indicating that visceral fat accumulation is more obvious and the risk of cardiovascular disease, type 2 diabetes and other diseases is also higher.

Limitations of BRI

It should be noted that BRI also has certain limitations. As a newer body assessment indicator, compared with BMI, BRI has less relevant research and is still in the stage of accumulation. At present, there is still a lack of sufficient long-term research data to support the specific change patterns and predictive value of BRI in different populations and different disease states.

In addition, the measurement is relatively complicated. If the measurement position is slightly different, the measurement results will have a relatively large deviation, and it is not conducive to repeated measurements, so errors are prone to occur.

In addition, body differences will also have an impact on the evaluation of numerical results. For example, higher muscle mass may lead to higher weight and waist circumference values, thus causing the BRI value to be overestimated and falsely indicating health risks.

For example, for some fitness groups with larger waist circumferences (such as high-level weightlifters, etc.), the BRI index will still be high, but this does not mean that they have a higher risk of chronic diseases.

There are also many women who have fat in their buttocks and thighs but not thick waists, commonly known as "pear-shaped figures." Fat accumulation in these areas can also cause related risks of metabolic chronic diseases, which cannot be ignored. Therefore, more and more studies have found that compared to women, middle-aged and elderly men have a higher accuracy in predicting chronic diseases using the BRI index.

In fact, whether you are using the BMI index or the BRI index, don't feel anxious because of a specific value. Choosing an active and healthy lifestyle and controlling body fat through active exercise and reasonable diet are the core values.

Planning and production

Author丨Yang Yizhuo, Lecturer, Sports Medicine Integration Innovation Center, Capital Institute of Physical Education

Zhao Qian, Rehabilitation Medicine Clinic Expert Rehabilitation Physician

Review丨Tang Qin, Director of the Science Popularization Department of the Chinese Medical Association, Researcher, National Health Science Popularization Expert

Planning丨He Tong

Editor丨He Yumeng

("Science Popularization China" WeChat official account)