Body Mass Index aka BMI is a relatively straightforward index to help determine a person’s weight category. Often used as a screening tool to see whether a person is overweight, underweight, obese, or healthy-weighted, the BMI is calculated using a person’s weight and height.
What is BMI?
Body Mass Index aka BMI is a relatively straightforward index to help determine a person’s weight category. Often used as a screening tool to see whether a person is overweight, underweight, obese, or healthy-weighted, the BMI is calculated using a person’s weight and height.
It is pertinent to understand that BMI cannot differentiate between the weight attributable to muscle and weight attributable to body fat. There are other methods available to particularly measure body-fatness viz. isotope dilution and skinfold thickness measurement, but since these are not readily available and are also costly, BMI is the most preferred way to see which weight category one falls in.
How to calculate your BMI?
Let us see how you can calculate your body mass index aka BMI.
BMI is calculated with a simple formula of BMI = kg/m2 wherein kg indicates the person’s body-weight expressed in kilograms and m2 is their height expressed in metres, squared.
This formula includes two things viz., how to calculate BMI in kg, and, how do you calculate BMI with height and weight.
On a generic basis, for male and female adults between the age group of 18 to 65, the World Health Organisation (WHO) classifies those with a BMI >= 25 to be overweight, and those with BMI >= 30 to be obese. So, for instance, your weight is 75 kgs., and your height is 1.50 m, then your BMI is 34.2, which makes you obese.
A common question that arises about BMI calculation is that ‘is BMI calculated differently for males and females? The answer is no. Only for calculating body mass index for children and teens, the gender difference is taken into account.
Limitations of BMI
Research has shown that BMI levels and the corresponding health risks they carry, differ as per different ethnicities, lifestyle factors, and environmental factors. It also differs in children and adults.
Additionally, the index is not suited for certain sets of people, as it may not give an accurate assessment of the weight category. For instance, BMI may not be correctly assessed in elders above the age of 65 because their muscle mass might be much lower than fat mass, and they may have a higher volume of fluid mass.
Same for pregnant or lactating women who have different body compositions altogether, thus making BMI a not-so-correct screening tool for their weight category.
An important tool towards good health
Nevertheless, irrespective of the aforementioned limitations, BMI is still considered an important health tool. On the backdrop of multiple risks associated with excessive weight, as well as less weight, it is necessary to understand your personal BMI and calibrate it to ideal levels as per your height, gender, and age.
Being overweight or obese puts you at risk of debilitating health problems such as Type 2 diabetes, heart disease, gallstones, respiratory problems, and some types of cancers, that stem out of high body fat.
While BMI is usually used for adults, in recent times, obesity has become a growing problem for children as well. As per WHO figures, in 2019, globally 38.2 million children below the age of 5, were overweight or obese.
On the flip side, being underweight increases the risk of anaemia, osteoporosis, irregular periods, premature delivery, and chronic fatigue. Underweight children are at a heightened risk of stunting (too short for their age) and wasting (too thin for their age).
Hence, one must take the advice of a qualified nutritionist to alter your eating habits so as to gain proper nutrition and reduce or gain weight in the correct manner. Crash diets, improper rigorous exercise, or eating junk food (to gain weight) will lead to even more serious problems and are thus not advisable ways to resolve weight issues.
Use the BMI Calculator to determine your weight category and consult a medical or nutrition expert to address the problems, if any, in an optimally safe and clinically advisable manner.
