What is BMI? Know everything about it

Obesity is associated with a variety of health conditions, including diabetes, fatty liver disease, and cardiac problems. People with a high BMI must take good care of themselves, which includes consuming a nutritious diet and exercising regularly.

But what did we just say about high BMI? You've probably heard of the word, but what does it mean, and why is it important to know your BMI? If you want to learn more about BMI, let's get started.

What is BMI? 

BMI stands for Body Mass Index. It is one of the tools to categorise your body fat percentage. Remember, it is an indicator, not a direct measurement. 

Having said that, the Body Mass Index (BMI) measures the person’s weight with respect to their height. BMI, more often than not, is associated with total body fat. Hence, the higher the BMI, the higher the fat percentage. 

As per WHO, a person having a BMI between 25 and 29.9 is considered overweight. A person having a BMI of 30 and higher is considered obese. On the contrary, a BMI below 18.5 is categorised as underweight, and individuals having a BMI between 18.5 to 24.9 are considered healthy. 

Is BMI a reliable indicator? 

There is no denying that BMI is a useful indicator when it comes to assessing your health, not individually but at the population level. However, it is to be noted that the distribution of fat is more reliable when it comes to assessing your disease risk. What we mean to say is that your waist circumference is a much better indicator of health risk than BMI.

Among other reasons, BMI calculation does not consider age or gender. As your muscle mass decreases with age and men tend to carry more muscle than women, these two situations are not factored in to offer an accurate assessment of one’s health. In addition, BMI does not distinguish between muscle mass and fat mass in its calculation. 

While BMI can be a reliable tool for health experts to understand your health status better, it is not a diagnostic tool to evaluate health conditions.  

How to calculate BMI? 

Your BMI is calculated using your weight and height. You may use the number with other health metrics to have an accurate assessment of your health, including your risk of heart disease and overall wellness.  

Here is the formula: 

BMI = (Weight in kilograms) divided by (Height in metres squared)

You can also use a BMI calculator if the calculation becomes complex

Even though the formula remains the same for every age group, the interpretation is different for children. 

For adults, this is how BMI results are interpreted 

BMI Measurement

Below 18.5 – Underweight

18.5 – 24.9 – Normal weight

25.0 – 29.9 – Overweight

30.0 and above – Obese

Health risks associated with lower or higher BMI

Both, a lower and higher BMI can put you at risk of developing health issues. If you are underweight and have a BMI lower than 18.5, you may develop the following health issues: 

• Weakened immune system, which is equal to more infections
• Infertility 
• Osteoporosis
• Anaemia 

On the other side, a higher BMI increases your risk for the following conditions:

• Heart disease
• High blood pressure (hypertension)
• Type 2 diabetes
• Gallstones
• Osteoarthritis
• Sleep apnea
• Certain cancers, including breast cancer, colon and gallbladder cancer
• Depression and other mental health conditions.

Please note, that a higher or lower BMI doesn’t necessarily mean you would have these conditions. You’re just at risk of developing the same. But it is a sagacious call that you maintain a healthy BMI to lead a healthy lifestyle. Consider gaining healthy weight if you have a lower BMI, and shed some weight if you have a higher BMI. Diet and lifestyle changes matter the most. 

Final thoughts

There is no doubting that body mass index (BMI) is a simple and free instrument that healthcare providers can use to assess your risk of certain health disorders. However, it should be emphasized that BMI is not always an accurate indicator of your health and well-being. If you want to learn more about your risk of developing health concerns, you should consult your doctor.