Body Mass Index BMI

What’s it about BMI & How is it Calculated?

Obesity is a global pandemic and weight loss is a key area of focus in today’s world, with the growing number of people suffering from preventable diseases like diabetes, hypertension, strokes and heart attacks. Health awareness has for once percolated down to all sections of society – the rich and the poor, the affluent and the commoner alike. This positive health trend has been the push that has generated a lot of interest in health promotion and disease prevention in our communities.

To make things simpler, there are various apps and tools to measure health parameters and one’s progress towards health. There are health monitors of every kind and most of them utilize various health parameters to indicate whether you are healthy or not and what you can do to improve your health. One very effective yet simple method to monitor your progress towards health is monitoring your BMI.

What actually is BMI?

BMI stands for Body Mass Index, which simply gives an indirect measure of your body mass made up of muscle, fat, and bone, based on your height and weight. Body mass index evaluates whether your body weight is proportionate to your height. BMI values indicate whether you are underweight, normal weight, overweight or obese

This might make some people think that BMI is a way to measure body fat, when it actually isn’t. Body Mass Index actually gives you a precise idea of body mass consisting of muscle, fat, and bone and not just body fat.

History of Body Mass Index

The original concept of Body Mass Index was devised by Adolphe Quetelet in the early Ninteenth Century. Due to this contribution of his, BMI is often referred to as “Quetelet Index”. However, the BMI in its present form was popularized by Ancel Keys who published a paper in the July 1972 edition of the Journal of Chronic Diseases suggesting its use for population studies.

Presently, there are hundreds of variants of this popular index which is regularly being used as a guideline for preliminary diagnosis.

How do you Calculate BMI?

BMI is calculated as a ratio of body weight in Kilograms (kg) divided by square of height in Metres (m). If Pounds (lb) and Inches (in) are used, you have to multiply with a conversion factor of 703.

BMI = Weight in kg / (Height in m)2

Every individual whose BMI is measured falls into any of the following categories based on The International Classification of Adult Underweight, Overweight and Obesity according to BMI:

- BMI <18.5        - Underweight
- BMI 18.5 to 24.9 - Normal or Ideal Weight
- BMI 25 to 29.9   - Overweight
- BMI 30 or >30    - Obesity

Besides this simple categorisation, BMI tables can also be used to evaluate your appropriate measurements. National Heart, Lung and Blood Institute has provided Body Mass Index Tables for your easy reference.

What makes BMI a useful tool to check your health status?

BMI is a key indicator of health as it is easy to measure without costly equipment – you just require your height and body weight! It is a relatively accurate and effective measurement for people over 18 years of age. However, it has its limitations when it comes to athletes, children, the elderly and the infirm.

A high BMI is associated with the risk of developing various modern-day diseases like obesity, hypertension, heart attack, stroke, gall stones, breathing problems, certain cancers and diabetes while an extremely low BMI may be associated with PEM (Protein Energy Malnutrition), propensity for recurrent infections and vitamin deficiencies.

Remember that higher your BMI, higher is your body fat and so is your risk of developing various diseases.

Risk Factors associated with High BMI

The following risk factors alongwith high BMI will put you at higher risk of developing heart diseases and other disorders.

  • Hypertension or high blood pressure
  • High LDL “Bad” Cholesterol
  • Low HDL “Good” Cholesterol
  • High Triglycerides
  • High Blood Sugar
  • Sedentary Lifestyle
  • Cigarette Smoking

If you are overweight or obese and have two or more of these factors, you better watch out as your chances of developing diseases associated with obesity shoots. The good news is that even minimal weight loss, just 5 to 10 percent of your current weight reduces the risk of developing these diseases.

Final Words of Advice

BMI Cartoon

A high Body Mass Index has been implicated as a cause of several diseases like obesity, hypertension, heart attack, stroke, diabetes, gall stones, breathing problems and some forms of cancers. It is wise to keep a watch on your weight and try to maintain your BMI between 18.5 to 24.9. If you are stretching your limits, consider a healthy diet and regular exercise to tone down your weight and waist.

For your convenience, you can use an online BMI Calculator to measure your BMI and keep a track of your progress towards a healthy future!

• Meet the Author • Dr. Lawrence Kindo


I am a Medical Professional with a passion for writing, blogging, playing, computers, and of course patient care. My writing in this medical blog will reflect my passion, and you are welcome to be a part of this venture. This medical blog is a tribute to all the great medical pioneers, and to the ultimate source of wisdom, God.


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