BMI is Immeasurable in Bodybuilders, but it is Still Used - Why?
How many bodybuilders who have honed their bodies have lost the BMI test, which measures the degree of obesity? But they are not obese or even have a meager body fat rate.
As an indicator of obesity, the body mass index BMI is completely dependent on height and weight, so it is impossible to distinguish the body fat content directly. However, even due to the particularity of the calculation formula, muscular bodybuilders with lower height are more likely to be classified as “severely obese.”
Even if there are measurement errors, BMI has long been officially recognized as an essential tool for measuring obesity rates and human health since it was invented in the 19th century. It is even used in authoritative journals such as The Lancet to observe national population health. This has also caused a lot of discussion among bodybuilders.
Suppose you want to quickly estimate the obesity trend of hundreds of millions of people worldwide. In that case, it is difficult to find an evaluation method that is stronger than the advantages of BMI’s low cost and high efficiency. After the BMI system was adopted by the World Health Organization (WHO), it was designed to be a global system. Compared with other evaluation methods, the cut-off values are the same for different genders and age groups.
Therefore, it is convenient to quickly estimate the average value and group obesity rate.
Most of the existing research on obesity, the fundamental investigation methods are derived from BMI statistics. Because when targeting the general public, the error rate of BMI is shallow.
In contrast, a more accurate body fat measuring instrument cannot consider the low cost and high effectiveness of BMI. At present, the only tool that can accurately measure body fat percentage is to use dual-energy X-ray absorptiometry, but domestic production technology is not available. Only large hospitals and institutes of physical education will import such equipment from abroad, each with a value of more than hundreds of thousands of dollars.
Although BMI was first invented to help the French army only, later on, it was used to assess all the soldiers’ average body fitness. But now, because of its cheap and efficient statistical method, it has been recognized worldwide as the best method to assess the obesity rate.
Bodybuilders Whose BMI Cannot be Measured
Although it is determined by height and weight, BMI reflects the body fat rate. For example, the “National Student Physical Health Standards” clearly stipulates that students of all grades include BMI in the assessment criteria. This is done to keep the obesity rate of students in check. If it exceeds the standard, the physical test results will be considered unqualified.
BMI cannot distinguish between fat and lean tissues, and it is also a shortcoming that cannot be accurately assessed for bodybuilders. For example, Schwarzenegger’s famous movie star, born as a bodybuilder, is 1.87 meters tall and weighs 105 kilograms. Therefore, it is easy to calculate Schwarzenegger’s BMI as 30 kg/m2. However, this standard is already classified as secondary obesity in the definition of the numerical table.
In addition, even if BMI shows people with the same fat content, their health status is difficult to predict. BMI cannot distinguish the fat content of different body parts. But fat distribution plays a decisive role in assessing a person’s health.
The distribution of adipose tissue also influences the risk of diabetes, cardiovascular disease, and other diseases. For example, the fat ring around the stomach is more likely to cause vascular calcification and heart disease than the fat pads on the thighs, buttocks, and arms.
For example, fat accumulated in the chest and abdomen makes the body look like an apple. In contrast, fat accumulated in the abdomen and lower parts (thighs and buttocks) causes the body to be pear-shaped. Even though the BMI values of the two are the same, apple-shaped obesity is considered a more accurate predictor of metabolic syndrome and cardiovascular disease. This is due to the accumulation of fat around the waist, increasing visceral fat content. As a result, the health risks of heart disease, diabetes, and cancer are higher.
In addition, a 2012 study showed that obese people assessed by BMI are healthier. The study showed that whether they are overweight or mildly obese (as determined by the BMI index), obese people have a 6% lower risk of death than normal-weight people.
Another study found that obese patients had a higher survival rate among hospitalized patients with pneumonia than normal-weight patients. This phenomenon is called the obesity paradox. Therefore, some people have also raised doubts about whether BMI can correctly assess body mass and health standards?
However, despite the increasing controversy, there are still a large number of studies that prove that BMI is highly correlated with the occurrence of multiple diseases. The BMI classification system has been widely used in population-based research to assess the risk of death in different types of BMI. It has also been used in specific etiology of death risk and has been found to be highly correlated.
An experiment that evaluated more than 60,000 patients in 2016 found that the use of total fat index (BF) is not as high as the correlation between body mass index (BMI) and cardiovascular disease (CVD) mortality.
Low-Cost, High-Efficiency BMI is a Public Health Indicator
In the past ten years, obesity experts have used the BMI data obesity classification system stored in the national database for decades to perform statistics and analysis. And continue to raise people’s awareness of obesity and its related health risks both nationally and internationally.
BMI is a valuable tool for this work. It is systematically summarized in the necessary education system of the medical profession and used as a statistical indicator to determine public health policies and large-scale social assessments. It even extensively invaded the consciousness of the general public.
The population data under BMI statistics have formed a massive database in various countries, and any newly formed statistical method cannot quickly create as much value as BMI data.
A census of more than 1,000 people in Norway conducted a hierarchical summary of BMI statistics that spanned ten years and found that socioeconomic status and education levels have increased significantly over the same period of 11 years, which is highly correlated with individual BMI. In addition, there is no more straightforward and more accurate method to measure the percentage of body fat than BMI.
Although the skinfold measurement test was once one of the practical methods to determine the body composition and body fat percentage, only well-trained and skilled testers can guarantee the accuracy of the measurement.
This test uses a particular skinfold caliper to measure the thickness of skinfolds at specific locations on the body, such as the triceps (back of the upper arm), abdomen (next to the belly button), etc., estimate the percentage of body fat. Moreover, the accuracy of body fat measured by sebum is as high as 98%.
And there are various restrictions. For example, only female subjects can perform measurements for female testers. In addition, the elderly are sometimes mistaken for the sebum layer because of excessive muscle weakness. The most important thing is that even if the same tester completes the test under similar conditions, the accuracy of the test is somewhat biased.
Scientific Guide to Physical Examination
Although the accuracy of measuring body fat content by BMI for fitness people is not high, the comparison of data at different stages can still reflect the results of exercise at this stage.
In addition, there are many other convenient and effective simple measurement methods. For example, measuring waist-to-hip ratio (WHR) and waist circumference (WC) may be a relatively efficient and straightforward physical measurement method.
Waist circumference can more directly reflect the degree of obesity than BMI. To make the data more accurate, try to ensure that the measurement is performed on an empty stomach, at the same time, and after non-vigorous exercise. It can also try to avoid large deviations in the data.
In the case of limited calculation methods and measurement, BMI can be regarded as a simple and quick measurement method. A point that needs to be noted here is that the actual degree of obesity cannot be judged based on the BMI calculation method for bodybuilders.
The fitness goal for bodybuilders is to regulate the lean mass they have and keep the fat mass to a minimum. Body fat percentage can be analyzed easily using the latest software technology called 3D body scanners like Visbody. Moreover, the overall body composition scale and the fat mass can be effectively measured through Bioelectrical Impedance Analysis (BIA).