Chances are, if you are conscious of your
weight and health, you will know what the body mass index (BMI) is and you will
know whether you are in a healthy range, according to the index.
No? Let us explain. According to Health24, BMI
is a simple index of height-for-weight, and is commonly used to indicate
overweight and obesity. It is calculated as follows:
calculated by dividing weight in kilograms by height in metres squared. For example,
if you are 1.65m tall and weigh 85kg: weight ÷ height squared = 85 ÷ 1.65 x
1.65 = 85 ÷ 2.72 = 31.25. The result is a BMI of 31.25.
According to the BMI, between 18 and 25 is a
healthy weight; between 25 and 30 is overweight; and anything over 30 is obese.
problem with BMI
Although the BMI is a simple mathematic
formula to use as a guideline, people have been questioning its accuracy. If
you’re extremely muscular and your number is over 30, would you still be
classified as obese?
While a number can be a good guideline, it has
often been said that doctors and medical practitioners cannot solely diagnose
patients as “obese” because of a number. They would need to take factors such
as medical history, body fat percentage, muscle-to-fat ratio and overall
fitness and diet into account.
Let’s take a theoretical case: A 30-year old
woman is 1.69 m tall and weighs 72 kg. She eats healthily and exercises five
times a week, including strength exercises and marathon training. Her body fat
percentage is 20% and her waistline is within the healthy region of less than
80cm in circumference.
If we do the maths, her BMI is 25.21 which is technically
overweight – a term you would definitely not use if you saw her in person.
This also means that many professional sportsmen
would be placed into the obese category, as their muscle density is greater
than that of a regular person.
Why BMI is
not that good
According to research, nearly half of the
people classified as overweight or obese are actually healthy when other factors
are taken into account.
And Robert Shmerling from Harvard’s Health
publication wrote in this article that BMI itself cannot measure health, but is
simply a number representing a person’s size.
While BMI might not be the be-all and end-all
of health, we should keep in mind that a healthy body weight lowers your risk
for chronic illnesses and other medical problems.
Doctors and health professionals will still
use BMI along with your medical history to determine whether you are overweight
or obese, but you will get a more accurate analysis by having your overall body
fat and muscle mass measured as well, according to Bodybuilding.com.
Instead of obsessing about the numbers too
much, you can maintain a healthy body weight by eating a balanced diet and
doing regular exercise without quick fixes or fad diets. It is also important
to monitor your weight as you grow older and to realise that your metabolism is
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