To recap what we discussed in an earlier blog: your BMI or Body Mass Index is a measurement of whether your height squared in relation to your weight is at a level that is beneficial to your health.

To calculate BMI we therefore take your height, e.g. 2 metres, multiply it by itself, i.e. 2 x 2 = 4. Then we take your weight, e.g. 100 kg, and divide it by the figure obtained in the first step. In this example 100 divided by 4 = 25, which means you have a BMI of 25.

In this regard it is important to know that BMI for women is calculated in the same way as for men, but for children and teenagers there are additional factors to take into account. 

But what does this all mean? How does one interpret the results?

A BMI below 18.5 is regarded as being underweight. If your BMI is between 18.5 and 24.9, you are in the safe zone, i.e. your weight is no threat to your health. With a BMI of between 25 and 29.9, you are entering the orange zone; you are overweight and if you don’t do something about the situation right now, you might end up being obese. This happens when your BMI is over 30, in which case your weight has become a threat to your health.

Take into account that any sudden, unexplained major change in BMI, even if you are not underweight or overweight, could indicate a problem somewhere. Visit your doctor for an evaluation.

A clinical analysis of your BMI/obesity level will also include the circumference of your waist and other risk factors. If your waist measurement is below the cut-off, but your BMI is within the healthy range, keep your weight constant and check your blood pressure, fitness and cholesterol levels.

In males, a waist bigger than 40 inches (101.6cm) is regarded as a health risk. For women the corresponding figures are 35 inches or 88.9 cm. Among Asian individuals those with a smaller waistline often have fewer health problems. In Asian females a waistline equal to or higher than 32 inches or 80 cm increases the risk of disease, while in Asian males the same is true if their waist size is equal to or more than 36 inches.

Those readers who are overweight, i.e. your BMI is between 25 and 29.9, or obese (BMI of 30 or more), and your waist measurement is more than 35 inches (female) or 40 inches (male), should visit a doctor. He or she will then assess your risk factors, such as high cholesterol, high blood pressure, type-2 diabetes and the damage to health caused by smoking.

If you are a high risk case, i.e. there are two or more risk factors present, the doctor might well recommend you lose weight, change your diet and get more exercise to reduce the risk that you could develop illnesses such as cancer, coronary vascular disease, peripheral arterial disease or coronary artery disease.