From Your Health Journal…..”A great article today from the New York Daily News by Tracy Miller called, “Is your BMI a lie? Formula that calculates healthy weight is flawed, says Oxford professor.” Body mass index, or BMI, has long been used as the quickest measure of whether a person’s weight falls within the normal range for their height. It is a chart that lets you know if your weight falls within a healthy range. You look up your height and weight, and where they meet on the chart corresponds to a certain number. For example, below 18 may be considered underweight, 18-25 may be considered normal, 25-30 may be considered overweight, and over 30 may be considered obese. At times, the BMI has received criticism because many experts felt it did not take into account lean body mass and water weight. Now, a mathematics professor says the formula is flawed. According to the professor, the good news: if you’re tall, you might lose a point or two, which could mean the difference between being obese and merely overweight, or overweight and normal. The bad news is for shorter people, who may gain a couple points. Please visit the Daily News site (link provided below) to read the complete article.”
From the article…..
The current body mass index formula is weighted against tall people, says mathematician Nick Trefethen, making them think they’re fatter than they really are. He proposes a new formula to straighten it out, and short people may not be happy.
The current BMI calculation gives tall people the short end of the stick, an Oxford mathematician says.
Body mass index, or BMI, has long been used as the quickest measure of whether a person’s weight falls within the normal range for their height. It’s calculated by your weight in kilograms divided by your height in meters squared. (Use a BMI calculator here.) A BMI in the range of of 18.5-24.9 is considered normal; 25-29.9 is overweight; and 30 and above indicate obesity.
But the current BMI formula is flawed, according to mathematics professor Nick Trefethen — which means there’s good news and bad news.
The good news: if you’re tall, you might lose a point or two, which could mean the difference between being obese and merely overweight, or overweight and normal.
The bad news is for shorter people, who may gain a couple points.
Trefethen, of Oxford University, says this is because the current calculation fails to account for something fairly obvious: tall people can take up more space without being fat.
“We live in a three-dimensional world, yet the BMI is defined as weight divided by height squared,” Trefethen wrote in a letter to the Economist, published January 5. “It was invented in the 1840s, before calculators, when a formula had to be very simple to be usable. As a consequence of this ill-founded definition, millions of short people think they are thinner than they are, and millions of tall people think they are fatter.”
He later clarified on his website, “I don’t believe that 2 should simply be replaced by 3. People don’t scale in a perfectly linear fashion as they grow. I believe a better approximation to the actual sizes and shapes of our bodies would be given by an exponent of 2.5.”
To read the full article…..Click here