The BMI (Body Mass Index) has become a very useful tool in the last 2 decades that helps to accurately measure the percentage of body fat. Not only is it easy to calculate but it also helps people manage their weight in a more scientific manner.
The BMI is an accurate and objective tool that will provide the relevant information we need in order to manage our weight.
The BMI takes into consideration both weight an height of a person. An easy method of calculating your BMI is to simply divide your weight in kilograms by the square of your height.
For example if a person is 5 ft 7 in tall (67 inches)
and weights a 120 pounds their BMI would be calculated in the following manner:-
Height : 67 inches / 2.54cm/inch = 170.18 cm which if we convert to meters is 1.7018 meters.
Height squared : 1.7018 x 1.7018 = 2.896 m2
Weight : 120 lbs / 0.454 kg/lb = 54.48 kg
Therefore, the BMI is 54.48 KG/ 2.896 M2 = 18.81 .
Once you have calculated your BMI you can compare it with the chart below to see if you are overweight, normal or underweight.
If BMI is under 18.5 = Underweight
Between 18.5 and 24.99 = Normal
Between 25 and 29.99 = Overweight
Between 30 and 34.99 = Obese (Class I)
Between 35 and 39.99 = Obese (Class II)
Any person whose BMI falls in the higher ranges is more at risk of developing various health problems such as coronary diseases, hypertension and diabetes. One should consult an experienced physician to get additional information and details on these diseases.
The BMI does have some limitations. It doesn't take into account the differences in gender. Women on an average tend to have a higher percentage of body fat in comparison to men. It also doesn't take into account different body types, age, muscle-fat ratio and athletic conditioning that differs from one individual to another. As a result, it might underestimate the BMI for older individuals who generally have lower muscle mass or overestimate the BMI for people who possess a more athletic body.
While calculating BMI another useful factor that can be taken into account is a person's waist circumference. This is particularly useful to know for both men and women since body fat tends to accumulate around the waist. For an average male measuring around 5ft 9in in height, a waist circumference of over 37 inches is significant whereas if it exceeds over 40 inches they may be at risk for several health problems. Among women who on an average measure around 5 ft 7 in in height, a waist circumference of 31 is considered high whereas, a waist of more than 35 inches indicates a health risk.
Even though the above just represent average figures, people with substantial waistlines know that they are at a greater risk of developing health problems by seeing the excess fat stored.
Though there is no single measurement that provides all the information we need to know about our weight, body fat and how to manage it, the BMI and waist circumference try and give us a useful and objective measure when considering a specific weight loss program.