In addition to BMI, data on body fat – for example waist circumference or a direct measurement of fat – should be used, the group recommended on Wednesday in the British journal The Lancet Diabetes & Endocrinology.
To calculate BMI, weight in kilograms is divided by height in meters squared. Currently, a BMI greater than 30 in people of European origin is considered an indicator of obesity.
For a long time now, specialists have criticized the fact that this value is not a direct measurement of fat, that it does not reflect its distribution in the body and that it does not provide any information on health and disease at the level individual.
More dangerous in some places
“Relying solely on BMI to diagnose obesity is problematic because some people tend to store excess fat at their waist or in and around their organs such as the liver, heart or muscles.” , explained Robert Eckel of the University of Colorado at Aurora, co-author of this article.
According to him, this means a higher health risk than excess fat directly under the skin in the arms, legs or other parts of the body. Additionally, people with excess body fat don’t always have a BMI that indicates obesity, so their health problems may go unnoticed.
The expert group suggests using different means of diagnosis, such as measuring waist circumference, waist-to-hip ratio or waist-to-height ratio in addition to BMI, or even a measurement direct from body fat. Only people with a BMI greater than 40 would then be considered to have excess body fat without the need for further confirmation.
Two categories
In addition to the new diagnostic guidelines, experts gathered around Francesco Rubino, from King’s College London, propose two new categories: “clinical obesity” for chronic disease associated with lasting organ dysfunction and “preclinical obesity” for the previous phase presenting health risks, but no chronic disease yet.
Different therapeutic strategies are needed in the two phases, according to the authors. The proposal from the “Commission on Clinical Obesity”, which brings together doctors from different specialties, is supported by 76 learned societies and patient associations around the world, as the article specifies.
It is estimated that there are more than a billion people suffering from obesity worldwide. In Switzerland, the proportion has doubled over the last 30 years: among men, it rose from 6% in 1992 to 13% in 2022, and among women from 5% to 11%, according to figures from the Office federal statistics office. This development is observed in all age groups.
