A new global definition of is reframing how doctors evaluate youth health, looking past traditional body mass index (BMI) measurements to focus on actual physiological impacts
According to research from the Murdoch Children's Research Institute in Australia, just 21% to 4.9% of children and adolescents qualify as clinically obese under the revised standard, compared to 7% to 10.8% under standard BMI calculations.
Dr Danielle Longmore, a pediatrician at the Melbourne institute, outlined the shift during an appearance on "Fox & Friends."
"There's a push to really understand the impact of on health," Longmore said "BMI is really just measuring size. So, it doesn't really have a way of capturing whether somebody is well or unwell."
The traditional BMI measurement calculates a person's weight relative to their height
The new definition, developed by an international panel of medical experts convened by the medical journal The Lancet, requires evidence of both excess body fat and related or limitations in daily activities
These indicators can range from elevated blood pressure and abnormal blood sugar to impaired mobility or poor sleep
Longmore noted that many children defined as obese by BMI metrics are active, , attending school and otherwise healthy
"I think this definition just really clarifies what people have been doing in actual ," Longmore said, noting that physicians typically evaluate patients for underlying complications rather than relying strictly on scale weight
While clinical obesity appears to be significantly less prevalent under the new model, the trajectory reverses dramatically later in life
The study, which analyzed nearly 800,000 individuals across their lifespan, found that clinical obesity rates climbed through adulthood
Among adults ages 65 to 74, the rate of clinical obesity reached 52%, as health problems linked to excess body fat became more common with age
The findings come at a time when prescription weight loss medications, particularly , are gaining in popularity
However, Longmore cautioned that the study's dataset reflects pre-GLP-1 records, making the long-term impact of these treatments an open area for future study
"This is really just the start of understanding what this new diagnostic entity means, and we really need more research," Longmore said, emphasizing that while the definition refines clinical diagnoses, early health interventions and remain critical for children at risk