Obesity: the Bmi paradox and lifts no longer suitable for the average weight

The Body Mass Index, the old body mass index, may be flawed, but woe betide if it is retired too soon. At the European Congress on Obesity (Echo 2026) being held in Istanbul, the Italian Obesity Society (Sio) takes a stand in the international debate that has been dividing experts and scientific societies for months: the Bmi may have clinical limitations, but it remains the main rapid, universal and almost cost-free screening tool today.

A stance that stems above all from a very real problem. According to data from the Itros study in Italy, presented at the congress, barely 17% of patients in Italy have their Bmi recorded in the general practitioner's file. In 83% of cases, even this basic measurement, which only requires weight and height, is missing.

'Neither perfect nor infallible, but indispensable,' summarises Sio president Silvio Buscemi. In the crosshairs of the Italian scientific society are the proposals put forward by the international community to overcome the Bmi as the main criterion for diagnosing obesity, replacing it with more sophisticated parameters based on organ damage, imaging or in-depth metabolic analyses. 'If we already cannot even weigh and measure patients on a regular basis,' notes Buscemi, 'introducing more complex systems risks making obesity an invisible disease. The fear is that overly articulated criteria will slow down diagnosis and access to treatment, especially in territorial medicine. For the Italian specialists, the problem is also organisational. "We cannot wait for the disease to produce one of its more than 200 complications before intervening," explain Sio. Hence the defence of a tool that may be considered crude, but is still fundamental for quickly intercepting those at risk.

The Istanbul congress, however, is also showing another aspect of the obesity emergency: that which directly concerns public spaces and infrastructure. In fact, one of the most discussed studies of these days comes from the United Kingdom and concerns European lifts, which, according to researchers, are designed on outdated standards with respect to the increase in the average weight of the population. The research coordinated by Nick Finer, president of the International Prader-Willi Syndrome Organisation and former professor at University College London, analysed 112 lifts produced between 1972 and 2024 in seven European countries, including Italia. The data show that the theoretical capacity of the lifts has basically stopped at the parameters of the early 2000s, while the average body weight has continued to rise.

In the 1970s the average weight in the UK was around 75 kilos for men and 65 for women. Today it is up to 86 and 73 kilos respectively. Yet many lifts continue to be designed assuming a standard weight of 75 kilos per passenger. For Finer, this is not just a technical or safety issue. "Public spaces are no longer designed with larger bodies in mind," warns the researcher, also pointing out the risk of discomfort and social stigma for people with obesity. The result is that the Istanbul congress ends up telling two sides of the same transformation. On the one hand a medicine that seeks more sophisticated tools to define and treat obesity as a complex chronic disease. On the other a society that often continues to be built on physical parameters from half a century ago.