Overnight, Millions More Americans Could Be Labeled Obese

7 in 10 US adults could meet new definition of obesity

BOSTON — A major shift in how doctors define obesity could fundamentally change medical practice, according to a groundbreaking study that analyzed health data from more than 300,000 Americans.

Scientists found that adoption of a new concept of obesity, endorsed by 76 professional medical organizations, increased obesity rate from 42.9% to 68.6% among study participants. This sharp jump is due to the inclusion of people with dangerous diseases. belly fat despite maintaining a weight that doctors previously considered healthy.

Published in The JAMA Network is openThe study analyzed data from the All of Us research program and represents the first large-scale study of how new recommendations on obesity will affect healthcare. The study tracked participants for four years to document real-world health effects, not just theoretical classifications.

Beyond Scale: Why Waist Size Matters

Instead of relying solely on height and weight calculation which has dominated medicine for decades, the new approach includes waist circumference, waist-to-hip ratio and waist-to-height ratio along with BMI to create a more comprehensive health assessment.

Under the new system, a person can be classified as obese for three different reasons:

Waist measurements use certain restrictions that vary depending on gender and race. For example, increased waist circumference is generally defined as 40 inches or more for men and 35 inches or more for women, although these thresholds are adjusted for different ethnic groups who may face health risks at lower sizes.

A research team led by Dr. Lindsey Fuhrman of Massachusetts General Hospital found that traditional BMI measurements miss many people with dangerous fat distribution patterns. The research team found that belly fat, independent of overall weight, served as a key predictor metabolic disease..

The scientists identified a category called “anthropometric obesity,” which affected 78,047 study participants. These people maintain normal BMI values ​​while maintaining elevated abdominal values. Among this group, 17,426 people (22.3%) had BMI values ​​that doctors previously considered normal or insufficient.

Health risks that BMI doesn't account for

The researchers tracked the participants to document who developed serious health problems. People with this form of latent obesity were at significantly higher risk than people without obesity, despite appearing healthy on standard scales.

Compared to people without obesity, people with thaliocentric type were 76% more likely to have organ problems. They also faced more than double the risk of developing diabetes and a 55% increased risk of cardiovascular disease.

The research team found that people with this form of obesity often develop high blood pressurephysical limitations and sleep apnea. These conditions usually occur gradually, making early detection through waist measurement potentially valuable for prevention.

Age and demographics are driving change

The study revealed striking patterns across different groups. Among participants aged 18 to 29 years, the prevalence of obesity by the new definition reached 43.9%. The most dramatic changes occurred among older adults: 78.3% of Americans over 70 years old in the study met criteria for obesity under the new structure compared to previous classifications based on BMI.

This age-related increase reflects how body composition changes over time, with more fat being stored. around the middle as people get older. Among people over 70 who took part in the study, 54.4% had what the researchers called “clinical obesity,” which indicates the presence of organ dysfunction or physical limitations.

The study also found notable differences by race and gender. Asian participants saw the largest relative increase in obesity rates, with the rate jumping 90.3% from 2,439 participants (27.0%) to 4,641 participants (51.4%) under the new definition. Male participants were more likely than female participants to be obese based on anthropometric measures alone: ​​32.5% of men versus 21.7% of women in the study.

Obesity treatment guidelines are due for a major overhaul

The new system could radically change who receives medications and treatments for obesity. Currently, about 45% of study participants qualify for weight loss drugs based on today's recommendations. Under the new approach, around half of these people would be moved down to lower priority for treatment as they would be classified as having early obesity.

Additionally, among participants with the most severe form of obesity under the new definition, approximately one in four would not qualify for current weight-loss medications. This discrepancy suggests that treatment recommendations may need to be seriously revised.

New guidelines recommend different treatment approaches. People with clinical obesity will be given the most aggressive treatment, including medication and surgery if necessary. Those with an earlier stage may receive lifestyle counseling first, with medications reserved for specific cases.

Clinical and preclinical obesity

The new approach introduces two categories depending on the presence of health problems. Clinical obesity means that a person has health problems or physical limitations that may be related to their weight. Tools for measuring “preclinical obesity” are available, but no serious health problems have yet emerged.

To define clinical obesity, doctors look for specific conditions, including high blood pressure, diabetessleep apnea, joint problems, liver problems, or physical limitations such as difficulty with daily activities. The presence of any of these characteristics along with increased body size may classify a person as clinically obese.

About 36% of all study participants were clinically obese, with rates increasing sharply with age. This distinction is important because people who are clinically obese face the highest risk of developing diabetes, heart disease and death in the future.

Even the earlier stage carries significant health risks. People with preclinical obesity had more than three times the risk of developing diabetes and a 40% higher risk of heart problems than people without obesity.

The study revealed the most common health problems associated with clinical obesity: high blood pressure topped the list, followed by physical limitations and sleep apnea. The study found that organ dysfunction itself, even without obesity, significantly increases health risks.

For health systems and insurance companiesthese changes could have huge financial implications. Medicare and other payers may need to reconsider coverage policies as the population eligible for obesity treatment potentially changes significantly.

The study authors acknowledge that implementing the new definition will require more work and resources than current BMI-based screening. However, they argue that the improved ability to identify health risks may justify the additional effort, especially if integrated into electronic health record systems.

Study obesity prevalence Using traditional BMI-based criteria (42.9%) is in close agreement with CDC estimates for the US population (40.3%), supporting the potential broader applicability of these results to American adults as a whole.

Disclaimer: This article summarizes recent peer-reviewed studies for general information only. This is not a substitute for medical advice. Readers should consult qualified health care professionals for individual evaluation or treatment.