From this year onwards and with the new definitions, there is a significant number of Americans who are obese.
If you have ever wondered, even for a moment, if you are obese, now is the time to check. A new research study suggests that more than two-thirds of Americans are considered obese according to the criteria released this year, which is much higher than previous rates of obesity.
Researchers from Mass General Brigham analyzed the medical records of a large and diverse sample of Americans and found that nearly 70% of people met the new criteria for obesity, which takes into account more measurements in addition to body mass index. Those classified as obese under this new definition had an overall higher risk of health problems compared to non-obese individuals, suggesting that these expanded criteria may help doctors detect these problems before they worsen, according to the study authors.
“Our findings suggest that the new definition of obesity effectively stratifies individuals according to the elevated risk of organ dysfunction and long-term complications,” the researchers wrote in the study published Wednesday in JAMA Network Open.
More than Body Mass Index
In January 2025, a large group of obesity experts from different parts of the world, backed by The Lancet, insisted on a drastic change in the way obesity is diagnosed. It was the culmination of years of movement by some doctors and patients who think beyond body mass index. The new criteria, outlined in a report that same month, are supported by many health and obesity organizations, including the American Heart Association.
Body mass index is calculated using a person’s weight and height, and traditionally, a person with a BMI over 30 was considered obese. The updated definition does not discard BMI but adds other measurements, which can also replace it. Measurements such as waist circumference, waist-to-hip ratio, waist-to-height ratio, and DEXA scan (which measures a person’s bone density and body fat) are included.
The authors of the criteria argued that the new definition makes it easier for doctors to determine if someone has excess body fat, which is one of the main reasons why obesity can have negative health effects. They also claimed that their criteria can better detect cases of clinical obesity – obesity with a high likelihood of being harmful and increasing the risk of other serious health problems – compared to the BMI system alone. However, the researchers say that their study is the first to comprehensively analyze the implications of applying these criteria in the real world.
Hidden Obesity
The researchers analyzed data from the All of Us program, a historic federal initiative that collects detailed health information from a diverse group of Americans. They looked at the long-term health outcomes of over 300,000 American adults.
With the previous criteria, 42.9% of people in the sample considered themselves obese, a percentage in line with the national obesity rate reported by the Centers for Disease Control and Prevention (just over 40%). But with the new criteria, the percentage of obese individuals rose to 68.6%, including 36.1% classified as clinically obese.
Almost all individuals who met the old criteria for obesity were also included in the new criteria that use BMI plus another measurement. And almost all new cases of obesity were individuals who appeared to have a “normal” BMI but had elevated levels of other measurements. Importantly, individuals with less stereotypical obesity were more likely to experience organ dysfunction and a higher risk of diabetes than those not classified as obese by the new definition. That being said, those with classic obesity still appeared to have a higher risk of health problems compared to obese individuals with a normal BMI.
The results indicate that the new criteria do not include those who would have been diagnosed as obese in the past, a finding supported by another study. Additionally, it could help doctors identify individuals with hidden excess body fat and obesity, according to the researchers. Early detection can ideally help doctors prevent or treat obesity-related complications, such as diabetes.
“Identifying excess body fat is very important because we find that even those with a normal BMI but with abdominal fat accumulation are at higher health risks,” said one of the lead authors of the study, Lindsay Fourman, an endocrinologist at the MGB Department of Medicine. “Body composition matters, not just the number on the scale.”
If the new system is widely adopted, however, it could have negative aspects. The authors note that nearly a quarter of individuals with clinical obesity in this study may not be eligible for new GLP-1 drug therapies, for example. Although clinical trials have found these drugs to be substantially effective for those with classic obesity, the question remains whether they would benefit those who do not fit within traditional obesity standards.
Impacto en los pacientes
“The implementation of the new criteria may have significant ramifications for patients, including current users of GLP1RA drugs, and creates the need to evaluate the use of anti-obesity medications in this population added under the new criteria,” the authors of the study indicate.
Traducción de Gizmodo US
This article has been translated from Gizmodo US by Lucas Handley. You can find the original version here.
