Body Mass Index (BMI)

The body mass index (BMI) is one of the most widely used measures to know if a person is at his or her indicated weight or what variations he or she needs to make to adapt it to a healthy range. The variables considered when calculating the body mass index are weight and height, for which the weight in kilograms is divided by the square of the height in meters.

This equation has been widely used over the years to determine a person's possible risk of being affected by weight-related diseases. In turn, BMI helps us to identify the presence of risk factors for diseases such as diabetes or various cardiovascular and chronic conditions.

During the development of this guide we will be going deeper into some of the basic elements related to Body Mass Index (BMI), so that you can incorporate this knowledge in your health care and the prevention of possible weight-related diseases.

Calculating the Body Mass Index (BMI)

As we said before, the Body Mass Index (BMI) is calculated through the equation (weight in kilograms divided by the square of the height in meters).

To better exemplify the above, let's take the following assumption:

• Carlos weighs 65 kg and is 1.73 meters tall;
• We proceed to divide 65 (which is his weight in kilograms) by 2.99 (which would be the result of calculating the square of 1.73, which is his height in meters)
• 65/2.99 gives us a result of 21.73, which would be Carlos' Body Mass Index (BMI).

How to interpret the result?

Once we have performed the above equation, we will proceed to interpret the results. To do so, three categories (underweight, normal weight and overweight) are taken as a reference.

Normal weight: People with normal weight are those with a Body Mass Index (BMI) between 18.5 and 24.9. Within this range, it is considered that the subject has a healthy weight, taking into account the height he/she has. Underweight: Underweight people are those with a Body Mass Index (BMI) below 18.5. In this case, it is likely that the subject needs a diet with abundant calories, which will bring him/her into a range that does not present risks to his/her health. Overweight: Overweight people are those with a Body Mass Index (BMI) higher than 24.9. If the subject is overweight, the risks of suffering from some of the diseases we have mentioned above increase, which is why it should be oriented towards a low-calorie diet and the incorporation of regular physical activity, in order to reduce their weight to a healthy range.

Problems with Body Mass Index (BMI)

Although the Body Mass Index (BMI) may be an attractive tool for weight control, there are some factors that make this mechanism not as accurate as it may seem. First of all, BMI does not take into account body composition, age, gender or muscle mass.

The aforementioned factors have an impact when considering whether or not a person is overweight, which is why if there are reasonable doubts, it is important that you visit a specialist, who will have other mechanisms to determine your state of health in relation to your weight. However, you can use it as a guide whenever you want to have an inaccurate reference of whether your weight is adequate or not.