Some factors such as the Body Mass Index or fat can determine whether a thin person can be considered obese.

Can you be thin and obese?

Have you ever considered that, despite being a small size, you can suffer from obesity? Is having this disease the same as being overweight? These questions have begun to take hold in recent years, as the proved that not everything is what it seems around obesity.

If we go out into the street we ask what people consider what is obesity, probably most of the answers would associate this disease with a high weight. It would not be unreasonable to think about it since this is what the studies carried out so far.

But nevertheless, obesity is not always correlated with excessive weight. Moreover, a person with normal weight (we will see later what is called ‘normal’ weight) and, even, a thin individual, can be considered obese.

As these statements may seem shocking at first glance, we will explain what are the rates proposed by the most recent research to diagnose this disease.

The controversial Body Mass Index

In the 90s of the last century, the World Health Organization and a panel of experts from the North American National Institute of Health recommended the use of Quetelet Index, also called Body Mass Index (BMI), to define different levels of obesity.

These diagnostic values ​​have endured over time and, until now, BMI has been considered the most universal method for diagnosing obesity. In fact, some modern electronic scales They have the ability to calculate it according to the result obtained from dividing the weight of an individual by the square of his height.

The value obtained gives an idea of ​​the subject’s body surface measured in kg / m². Thus, it is considered that a person has low weight when the BMI is less than 18.5, has a normal weight if it is between 18.5-24.9. Overweight is considered when it is between 25-29.9 and above 30 we would speak of obesity.

But nevertheless, recent scientific studies They are beginning to extract evidence to show that the use of this popular value could be numbered. This has happened because this meter, now called “classical diagnosis of obesity”, has limitations of use.

For example, a muscular subject after long hours in the gym may present a high BMI value and yet not have obvious obesity.

Another example is seen in pregnant women, in people who suffer from fluid retention or in children and adolescents. It can also occur in subjects of short stature, in elderly individuals, and even among different races and ethnicities.

Body fat, a key value

Perhaps we should be clear about what is considered obesity. The Spanish Obesity Society defines it as a chronic disease characterized by an increase in fat mass within an individual’s body composition.

In other words, it is not about evaluating the increase in weight above experimentally defined values, but rather the content of body fat mass.

On average, it is understood that in males, the proportion of normal fat mass is between 12% and 20%, while in women it is between 20% and 30%. When these values ​​exceed 25% in men and 33% in women (regardless of BMI), the individual is considered obese.

By now we should be clear that obesity may or may not be related to a high score when stepping on a scale. But the truth is that it is the high amount of body fat that makes the difference.

Therefore, this data should be the one that really worries us, since excess fat in our body is a factor that increases the risk of disease cardiovascular

In this sense, to determine the probability of suffering this type of disease, we must also look at the place where this fat it is lodged in our body.

This is the reason why other anthropometric measurements that will facilitate diagnostic work. For example, knowing the waist circumference, the waist-hip ratio, and the waist-height ratio help to accurately determine the level of risk.

Obesity without excess weight

Now, back to the beginning, could a person of normal weight be considered obese? As we have seen, if we only attended the IMC, it would not be possible.

But if we take into account other research that not only evaluates weight, but also how it is distributed in the body, yes there would be possibility. That is, it would be necessary to identify which part is lean mass and which part is fat.

Therefore, anyone, regardless of their weight (and, by extension, their BMI), could become obese when their fat exceeds the amounts mentioned. It is estimated that up to 22% of the world’s population could be obese without excess weight.

These data indicate that in the population there is a dangerous level of cardiometabolic risk hidden because, based on the old widespread ideas, we tend to think that if our weight is correct, we should not worry. We are only alarmed when the famous michelin squeezes us.

* This article was originally published on The Conversation.

* Antonio Fernando Murillo, Professor of Nutrition at the University of Almería.