16.5% of men over the age of 18 and 15.5% of women suffer from obesity in Spain, according to figures from the 2020 European Health Survey, while 44.9% of men and 30.6 % of women are overweight. The World Health Organization has long warned that overweight and obesity pose a high risk of non-communicable diseases such as "cardiovascular, heart disease, diabetes, musculoskeletal disorders and some types of cancer (endometrial, breast, ovaries, prostate, liver, gallbladder, kidneys and colon). This body warns that since 1975 obesity has tripled worldwide and that "the majority of the world's population lives in countries where overweight and obesity claim more lives than underweight (low weight for age )”.
The WHO defines overweight and obesity as an abnormal or excessive accumulation of fat that can be detrimental to health. “Body mass index (BMI) is a simple indicator of the relationship between weight and height that is frequently used to identify overweight and obesity in adults. It is calculated by dividing a person's weight in kilos by the square of their height in meters (kg/m2)”, indicates this body, which establishes overweight as a BMI greater than 25 and obesity as a BMI greater than 30.
However, currently the body mass index is considered an obsolete measure when it comes to calculating the ideal weight, among other things because it does not distinguish parameters such as the percentage of fat or muscle mass, determinants when it comes to knowing the state of a person's overall health beyond the number indicated on the scale. Dietitian-nutritionist Teresa Chueca explains it: “This index was originally called the Quetelet Index (QI), since it was created in 1830 by Adolphe Quetelet, a Belgian mathematician, sociologist, astronomer and statistician. A population of white European men was used as a reference to describe the "ideal man", but even Quetelet himself warned that this formula is not valid to determine the state of health of people, but rather to be used for purely statistical purposes" .
Initially, Quetelet established a healthy BMI of 28 for men and 27 for women, but this figure was lowered in 1998 “through an alliance between the United States Institute of Health and various pharmaceutical companies, which caused millions of Americans to they went to sleep with a normal weight and woke up overweight.” For Chueca, some of the drawbacks of using the BMI as an indicator to establish an ideal weight, something that many health professionals still do today, is that it is a formula based on white, middle-class European men, who are not they take into account factors such as age, sex, bone structure or fat distribution and, what is worse, "that it is not a good indicator of health, since it is a figure that can classify cardiometabolically obese people healthy and vice versa: defining people with compromised cardiometabolic health as 'normal'”, explains the nutritionist.
Xavier González, dietitian-nutritionist at CreuBlanca, in Barcelona, agrees with her: “BMI is a value that is now obsolete, since it only indicates the relationship between weight and height. But what about the weight? What kind of weight are we talking about? Fat or muscle? Today what we have to use to check the state of health of people is not the weight, it is the fat profile. This can tell us what quality of life a person has. That is why there are different techniques that help to know that value, such as bioimpedance scales or anthropometry. With this, precision is gained and the values are much more determinant to know the state of health”.
This is also explained by the doctor and nutritionist Núria Monfulleda, from the Loveyourself center in Barcelona: “It is important to forget the overall weight that the scale marks and look at the percentage of fat, which is only part of the total weight. The figure we get when we weigh ourselves is a combination of bones, muscles, water and fat, so the more muscle we have, the more we will weigh, but the important thing is to know how much fat we have”. The expert affirms that in the case of men a percentage of healthy fat is between 10% and 25%, while in women this should range between 20% and 32%. “You have to stay on this fork. Then it is up to each person to decide what effort they want to make to locate themselves in one or another point of it, always knowing that any weight that includes these figures will be healthy.
Monfulleda warns that “going below these fat percentages is generally not recommended, in addition to being very difficult to achieve, since it is less than what the body needs. Being above that percentage of fat is considered overweight and, therefore, it is not healthy”. Thus, there is no single ideal weight, an optimal figure (back in the 90s it was even said that the ideal weight was ten kilos less than one's height), but wide ranges in which a person can have a healthy weight, always in depending on factors such as age or gender.
González, for his part, points out that bioimpedance scales are "good tools for knowing both weight and fat percentage, muscle mass, visceral fat profile, water percentage, etc." He warns, however, that "these values do not have high precision if they are not used correctly. Most scales calculate the values based on the water profile in the body at the time of weighing. It is a problem, since the water profile is highly variable throughout the day due to different factors (sports, humidity, fluid and food intake, hormonal or menstrual situation...) and if the measurements are not carried out in the same conditions, it can generate errors in the calculation of the values”.
Used well, however, it allows users to get some surprises that couldn't be detected by following indicators such as body mass index. “There is a possibility that a person who is underweight may have a high fat profile at a time when they are muscularly weak, or have very low muscle mass. The same happens the other way around: a person with a high weight does not have to be a person with a high percentage of fat, but can simply have a high muscle mass. Therefore, he agrees with Monfulleda that “there is no single perfect weight for a person. The ideal weight is the range of weights that are affected by a person's fat profile and muscle mass, among other factors. It is not a single value, but a range of possibilities where the total weight is not enough to be used as a reference”, explains the expert.
All the experts agree that it is essential to prevent overweight and obesity, which is achieved by following a varied Mediterranean diet, rich in fruits, vegetables, legumes and vegetables. Just as in the past the guideline for healthy eating was the classic food pyramid, which was based on the consumption of carbohydrates, in recent times the so-called Harvard Healthy Plate, prepared by scientists from this university, rules. This recommends, roughly, that 50% of our daily intake be fruits and vegetables, accompanied by 25% healthy protein and 25% cereals and whole grains. The reference fat must be vegetable, preferably from olive oil. Regular physical exercise and good sleep hygiene also contribute to maintaining a healthy weight.
The figures, however, are not encouraging. According to the WHO, in 2016, 39% of adults aged 18 or over were overweight, and 13% were obese, something difficult to reverse if socioeconomic and cultural factors are not taken into account, which are often ignored in the obesity research. This is stated by a team of sociologists from the Universidad Juárez Autónoma de Tabasco, in Mexico, who in their article Overweight and obesity: a proposal for an approach from sociology, point out that "obesity and overweight go beyond the biomedical perspective and are a problem of social and gender inequality, so a social approach is necessary to understand its roots”.
This document also points out that "in the disposition to maintain a "normal" weight, the sociological analysis maintains that people make decisions about the type of food, drinks and exercise, but they do not do so freely, since they are not alone in this. On the contrary, there are given or inherited life conditions that function as structures that condition the possibilities of existence, forcing one to choose some practices and disdain others, including those that are positive or negative for health”. The same occurs in reference to regular physical exercise, key to maintaining good health and preventing obesity, which is not available to all people to the same extent. “The strategy of recommending physical exercise for the entire population negates the gender, ethnic, and class inequalities that underlie the phenomenon of overweight and obesity,” the authors conclude.
