A study led by Prof. Dror Dicker of Hasharon Hospital has led to a major shift in how obesity is defined in the United States, with around 50 million people now reclassified under new medical guidelines. 

The findings were published this week in the Annals of Internal Medicine.

The peer-reviewed research is based on a diagnostic framework introduced by the European Association for the Study of Obesity (EASO), which expands the definition of obesity beyond the traditional body mass index (BMI) system. 

The study analyzed data from 44,030 adults in the US who participated in the National Health and Nutrition Examination Survey (NHANES) between 1999 and 2018.

18.8% of adults previously classified as overweight are now considered PWO

According to the new EASO criteria, individuals with a BMI between 25 and 30—traditionally considered overweight—may now be classified as having obesity if they exhibit significant abdominal fat and obesity-related health conditions. This is measured using a waist-to-height ratio higher than 0.5, combined with the presence of comorbidities.
5 months into the war: half of the Israelis gained up to 5 kg in weight (credit: SHUTTERSTOCK)
5 months into the war: half of the Israelis gained up to 5 kg in weight (credit: Albert Arhó)
As a result, 18.8% of adults previously classified as overweight are now considered People With Obesity (PWO). The most common health issues identified among this group include high blood pressure (79.9%), arthritis (33.2%), diabetes (15.6%) and cardiovascular disease (10.5%).

The study found that the mortality risk among this newly identified group was similar to that of individuals with normal weight. However, when compared to healthy individuals with normal weight and no underlying conditions, the PWO group showed a significantly higher risk of death. 

Mortality risk was also higher in this group than in those who remained categorized as overweight under both the traditional and updated definitions.

In Israel, the findings may also affect how obesity is diagnosed. According to Hasharon Hospital, a significant number of people in the country are not currently diagnosed with obesity, but would fall under the new classification. This may place them at increased risk of serious health complications.

“The new definition may allow us to identify obesity earlier and prevent life-threatening complications,” Dicker said in a statement released by the hospital. “We understand today that obesity is not just a number on a scale, but a complex chronic disease with significant health effects.”

The study was conducted by Dicker, Prof. Orna Reges of Ariel University and Dr. Thomas Krafty of the Holon Institute of Technology. It was funded by Ariel University and the Holon Institute of Technology.

Researchers noted that further studies are needed to determine whether individuals identified under the new criteria would benefit from the same treatments currently offered to patients with traditionally defined obesity.