The current BMI-based method of diagnosing obesity can both overestimate and underestimate obesity, says a group of 58 international experts.
The group estimates that the current definition may be misleading and provides insufficient information about health at the individual level. Body fat is usually considered excess when it exceeds 25 percent of total body weight in men and 30-38 percent in women.
The new definition focuses on how excess body fat affects the body, instead of relying only on the BMI body mass index, which combines a person’s height and weight.
The Lancet’s Diabetes & Endocrinology – report, obesity is generally considered a precursor to other diseases, not a disease in itself. Now they want to classify obesity as one of the chronic diseases.
BMI does not give the full picture
More than one billion people in the world suffer from obesity, and five million people die each year from diseases such as diabetes and cardiovascular diseases.
BMI has long been used to diagnose obesity because it has been easy to use. However, it does not give a complete picture of a person’s health because it does not take into account differences in body composition, Nature magazine write.
People of European background are usually defined as obese if they have a BMI of 30 or higher.
– However, a muscular athlete may be labeled as obese based on BMI, while someone with a normal BMI may have excess fat, which increases the risk of heart problems or other serious health problems, says the leader of the group that proposed the new approach, a bariatric surgeon at King’s College London Francesco Rubino.
Therefore, Rubino and his colleagues propose a new method of diagnosing obesity, combining BMI with other methods, such as measuring waist circumference or scanning the body with low-level X-rays to measure fat mass.
The Finnish expert does not see that the method as such is suitable for direct use in Finland.
University of Helsinki professor and chief physician of the HUS weight control house Kirsi Pietiläinen says that the body scanner is too complicated and expensive for public health care.
– If you want to measure body composition with a very reliable measurement method, such as the DEXA scanner proposed here, there are no resources for such in Finland. In a research spirit, we use the method in obesity studies, Pietiläinen says.
In addition, according to him, the scanners are typically so small that very fat people could not even fit in them.
Pietiläinen’s own research data shows that waist circumference and BMI index are strongly correlated.
– In addition, the body mass index is kinder than waist circumference measurements in telling about possible extra fat, which is harmful to health.
Medical history and lifestyle survey as a diagnostic aid
– When diagnosing obesity, standard laboratory tests, medical history and lifestyle information should also be used, says the study’s co-author, an endocrinologist Robert Eckel From the University of Colorado Anschutz Medical Campus.
According to Eckel, the traditional assessment method leads to unnecessary treatment for some people, while those who need treatment are not offered it.
Pietiläinen emphasizes that doctors in Finland, when evaluating obesity and its possible treatment methods, always look at the patient’s overall situation.
– We don’t just look at the body mass index, we evaluate the current health and make a prediction about the patient’s future state of health. In Finland, the aim is to help patients as early as possible so that new diseases do not develop due to obesity, he states.
However, according to the chief medical officer, the most important thing is that obesity is treated.
– The question is rather whether we have the resources or can afford not to treat obesity.
Pietiläinen, who also serves as the chairman of the adult obesity treatment recommendation working group, says that the recommendations will be updated in the near future and then a position will also be taken on the definition methods of the international group of researchers.
You can watch more about Akuutti-live’s Direct talk about obesity program.