Is BMI an accurate measure of body fat or fat?

Body mass index or BMI, long considered a standard for measuring a person's body fat, may not be as accurate as long thought, according to a new study.

A group of Michigan State University scientists and Saginaw Valley State University measured BMI of more than 400 college students - some of them were athletes and some did not - and they discovered that in most cases, a student's BMI does not accurately reflect the percentage of that student's body fat.

This study is published in the Health and Medicine edition of Sports and Sports magazine, an official journal of the American College of Sports Medicine.

BMI is calculated by the formula : taking a person's weight divided by the height of his or her square. Normally, a BMI of 25 or over 25 indicates that the person is overweight; 30 or over 30 said the person was obese. A person with a higher BMI is thought to be at higher risk for heart disease, diabetes and other health-related problems.

'The underlying problem is a similar standard for calculating BMI that is used for everyone' Mr. Joshua Ode, PhD student of the University of Michigan Kinesiology Department of Mechanical Engineering Research and an associate professor of this specialty at Saginaw Valley University. 'Whether you are an athlete or an old 75-year-old, all the same cutpoints are used.'

'BMI should be used carefully when classifying fatness, especially for college-age people,' said Jim Pivarnik, professor of human and epidemiological movement. University of Michigan said. 'BMI is really ineffective when it comes to how much a person really is.'

This problem, especially for young people and athletes is in place, BMI does not distinguish between body fat and muscle mass, Ode said.

He said: 'A previous study of football players at the National Football League found that most of these players - about 60% - are considered fat,' he said. 'But when you look at such a player, you will notice that in many cases, he is not fat. Many players who have a large BMI are due to muscle mass, but in many cases they are not fat. '

Professor Pivarnil said, the answer is that instead of having a cut point for everyone, there should be different classifications for different people.

'Is BMI 25 being overweight and 30 being fat the right indicators to use for people 20 to 29 years of age not in terms of risk?' He asked. 'It may be as simple as this: If you exercise regularly or you are an athlete, maybe your BMI 28 is overweight for you and 33 is considered obese.'

BMI is used as a 'representative' for fat, although body fat actually does not match this formula.

In their research, Mr. Ode and Pivarnil carefully measured height and weight to calculate the BMI of more than 400 student-age people. They then used a standard method to measure body fatness and they discovered that BMI did not provide an accurate picture of how many students had fat.

Thanh Van