When someone steps on the scale and sees a few extra kilos, the first question is usually the same: is this already overweight? The medical response does not depend on an absolute number of kilos, but on the relationship between body weight and height of each person, expressed through the body mass index (BMI).

BMI is calculated by dividing weight in kilograms by height in meters squared (kg/m²). It is the tool used by the World Health Organization (WHO) and most health systems to classify the nutritional status of the adult population:

This means that two people with the same amount of “extra pounds” can be in different categories based on their height. For example, five kilos above the weight considered normal can mean slight overweight for someone of short stature, but be almost imperceptible in a very tall person.

Why BMI is not an absolute truth

Various specialists in nutrition and endocrinology point out that BMI is useful as a population indicator, but it has important limitations at the individual level:

For this reason, many professionals complement BMI with other measurements, such as waist circumference or body fat percentage, to have a more complete picture.

How many kilos are “extra”?

There is no universal number of kilos that marks the border of overweight, because that border changes depending on the height of each person. What does exist is a healthy weight range for each height, calculable from BMI.

Exceeding that range by any amount is already technically classified as overweight, although the actual impact on health depends on other factors: diet, physical activity, family history, and body fat distribution.

Expert recommendation

Health professionals agree on one point: the figure on the scale is only a starting point. Before drawing conclusions about your own weight, it is best to consult with a doctor or nutritionist, who can evaluate the BMI along with other indicators and each person's health history, instead of basing any decision solely on a number.

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