Study finds seven in ten adults are obese – Earth.com
Study finds seven in ten adults are obese
An expanded definition of obesity does more than raise the headcount. It redraws the line between people who qualify for treatment and people who do not. The line moves in both directions at once
Where the new definition began
The framework did not emerge from a single laboratory. A commission convened by The Lancet Diabetes & Endocrinology published its report on Jan. 14, 2025, after nearly 30 months of work
A panel of 58 experts built the consensus under Professor Francesco Rubino of King’s College London. The group included clinicians, researchers, and people living with obesity
At least 76 professional organizations have since endorsed the new criteria. That level of backing gives the framework unusual momentum for a diagnostic change
The commission built the definition around a specific complaint. Body mass index alone tells a clinician almost nothing about where a patient stores fat
BMI was never a diagnosis
Adolphe Quetelet, a Belgian statistician, devised the height-and-weight ratio in 1832. He wanted to describe populations, and he showed no interest in obesity at all
The physiologist Ancel Keys renamed the formula the body mass index in 1972. He recommended it for population studies and warned against applying it to individual patients
American medicine ignored that warning. The National Institutes of Health adopted BMI thresholds in 1985. The agency then set the familiar cutoffs of 25 and 30 in 1998
BMI has therefore governed U.S. obesity diagnosis for roughly four decades, not for two centuries. The formula is old, but its role as a gatekeeper is recent
Two ways to qualify now
The new definition opens two routes. A patient qualifies through elevated BMI plus at least one elevated waist-based measure. A patient also qualifies through two elevated waist-based measures with a lower BMI
Researchers at Massachusetts General Hospital and Harvard Medical School applied both routes to 301,026 adults. The participants came from the All of Us Research Program
Prevalence climbed from 42.9 percent under the traditional standard to 68.6 percent under the new one. The second route accounted for 78,047 participants
Roughly one in four of those newcomers carried a BMI in the normal or underweight range. The rest sat in the traditional overweight category, a detail that early coverage often blurred
Clinical and preclinical obesity differ
The commission split obesity into two tiers. Clinical obesity requires at least one of 18 obesity-related conditions or a documented physical limitation
Preclinical obesity means excess adiposity without that damage. The commission recommends lower urgency and intensity of care for this group, reserving drugs and surgery for selected cases
In the cohort, 36.1 percent of all participants and 52.7 percent of those with obesity met the clinical bar. Hypertension, physical limitation, and obstructive sleep apnea led the list of qualifying conditions
That split turns a diagnosis into a triage instrument. It sorts patients by organ damage rather than by weight alone, which explains why the framework matters far beyond a prevalence statistic
Who gains and loses eligibility
Current prescribing rules for anti-obesity drugs still run on BMI. Under those rules, 44.7 percent of the cohort qualified for medication
The overlap with clinical obesity proved poor in both directions. About 22 percent of people with clinical obesity failed to meet current eligibility rules. That group includes patients with a low BMI, central fat, and organ damage
Roughly half of the currently eligible group lacked clinical obesity altogether. Many of those patients would fall outside the trial criteria and FDA labeling that govern today’s prescriptions
The finding raises questions the current rulebook cannot answer. It “brings up interesting questions about obesity medications and other therapeutics,” said Dr. Steven Grinspoon, senior author of the study
Age tilts the whole picture
Older adults absorb most of the change. Among participants 70 or older, 78.3 percent met the new criteria, and more than half met the clinical standard
Muscle mass falls with age while fat migrates toward the abdomen. The scale barely moves, so BMI misses the shift entirely
The Centers for Disease Control and Prevention flags waists above 40 inches (102 centimeters) in men and 35 inches (89 centimeters) in women. Those numbers catch what a weight reading cannot
The study authors flagged the cost consequences directly. Public payers such as Medicare would shoulder much of any sudden expansion in the treatment-eligible population
What the framework leaves unresolved
The researchers stopped short of claiming the new definition settles anything. It creates two categories that almost no one has studied properly
Nobody knows what drives waist-based obesity in people with an ordinary BMI, or which treatments work best for them. Exercise and certain drugs shrink visceral fat without changing weight, which makes them plausible candidates
Preclinical obesity also proved less benign than the label suggests. That group carried elevated risks of diabetes and cardiovascular events, though not of death
“We need to better understand what treatment approaches to prioritize,” said Dr. Lindsay Fourman, co-author of the study
Why the change matters now
Diagnostic criteria rarely make headlines, yet they decide who insurers cover and who clinical trials enroll. This one arrives during a boom in obesity medication
Recent work has already complicated the old picture. Genomic studies find at least 11 forms of obesity, and stress and inequality shape risk alongside biology
Researchers continue to map how drugs such as semaglutide act on the brain. Other teams report that obesity genes now hit harder than they did 50 years ago
Adoption will test whether clinicians can measure waists reliably at scale. It will also test how patients respond when a familiar number stops determining their health decisions
The full study was published in the journal JAMA Network Open
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