Study Shows Higher Obesity Prevalence When Using Anthropometric Measurements
In This Article
- New obesity criteria from the Lancet Diabetes and Endocrinology Commission use anthropometric measurements and BMI to create a new obesity classification
- A Massachusetts General Hospital study showed a 60% increase in the number of Americans with obesity when using anthropometric measurements
- About 1 in 4 Americans have anthropometric-only obesity, defined as elevated anthropometric measurements despite a non-elevated BMI, according to the study
- People with excess central adiposity and normal BMIs have a similar risk of cardiometabolic diseases and mortality as those with high BMIs
New research from Massachusetts General Hospital suggests America’s obesity epidemic may be worse than projected. The researchers applied new obesity criteria introduced by the Lancet Diabetes and Endocrinology Commission in early 2025, which use anthropometric measurements and body mass index (BMI).
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“The prevalence of obesity rose by almost 60% when we applied the new criteria to the more than 300,000 Americans who are part of the All of Us Research Program cohort,” says Lindsay Fourman, MD, an endocrinologist at Massachusetts General Hospital. Dr. Fourman is co-first author of the JAMA Network Open study, “Implications of a New Obesity Definition Among the All of Us Cohort.”
These findings suggest that as many as 70% of Americans have obesity—a significant increase from the 40% obesity prevalence estimated by the Centers for Disease Control and Prevention (CDC) using the traditional BMI-based definition. The increase was especially notable among adults 70 and older and people of Asian descent.
The research also showed that an estimated 1 in 4 Americans has anthropometric-only obesity, or obesity diagnosed by elevated anthropometric measurements despite a non-elevated BMI. “If you’re just looking at BMIs, these patients don’t fit the definition of obesity,” says Dr. Fourman. “However, their measurements of body fat distribution suggest they have excess fat that places them at a higher risk of cardiometabolic diseases and mortality.”
About the New Diagnostic Criteria for Obesity
BMI has been in use for almost 100 years as a health screening tool—and for decades, healthcare professionals have lamented its limitations. Most notably, BMI doesn’t distinguish between muscle and adiposity. Nor does it show where fat is distributed in the body.
“We know that excess abdominal fat increases the risk of insulin resistance, metabolic disease, and cardiovascular disease more than gluteofemoral fat,” says Dr. Fourman. “By only looking at BMI, we overlook an entire population of patients carrying excess abdominal fat despite normal BMI who face the same health risks as those with high BMIs.”
Combining Anthropometric Measurements With BMI
The Lancet Commission criteria combine BMI with anthropometric measurements to offer a clearer picture of body composition and fat distribution to better identify people at risk for obesity-related conditions.
These anthropometric measurements include:
- Waist circumference
- Waist-to-height ratio
- Waist-to-hip ratio
Classifying Anthropometric Obesity
The Lancet Commission obesity definition can be subdivided into two mutually exclusive groups:
- BMI-plus-anthropometric obesity: A patient has a BMI greater than 30 (or greater than 27.5 if Asian) and at least one elevated anthropometric measurement. Or a patient has a BMI greater than 40.
- Anthropometric-only obesity: A patient has at least two elevated anthropometric measurements and a BMI below 30 (or 27.5 if Asian).
Distinguishing Between Preclinical and Clinical Obesity
The new criteria also distinguish between preclinical and clinical obesity:
- Clinical obesity: A patient with obesity has an obesity-related health condition, such as sleep apnea, heart disease, liver disease, or joint pain, or impaired physical function.
- Preclinical obesity: A patient with obesity doesn’t have obesity-related health conditions or impaired physical function. But without interventions, they may be at risk of developing clinical obesity.
What the New Criteria Mean to Providers and Patients
The rise in the number of Americans with obesity was driven by expanding the criteria to include anthropometric measurements. “There needs to be more research into why some people are more prone to excess abdominal fat,” says Dr. Fourman. “And we need to better understand what treatment approaches to prioritize for this patient population.”
More than 70 organizations, including The Obesity Society and the American Heart Association, endorse the Lancet Commission obesity criteria. Here’s what a redefining of obesity could mean for providers and patients:
Making Anthropometric Measurements Part of Physical Exams
Anthropometric measurements could become part of a patient’s physical examinations, much like taking their blood pressure and temperature. “With basic training to ensure measurements are taken in standardized locations, medical teams can readily incorporate these measures into routine practice,” says Dr. Fourman. Like BMI, these measurements can help providers track health risk over time.
Another group of Mass General Brigham researchers found that using an MRI with an artificial intelligence (AI) tool could accurately measure subcutaneous adipose tissue, visceral adipose tissue, skeletal muscle, and skeletal muscle fat fraction in minutes. Their findings, published in the September 2025 Annals of Internal Medicine, showed that body composition measurements could predict cardiometabolic risk beyond information gleaned from BMI.
Changing Patient Perceptions on Obesity
Patients with excess abdominal fat may be more motivated to make changes when providers explain they have a diagnosable condition—anthropometric-only obesity—that significantly increases their risk for health problems. “This new definition gives providers the language and tools to open discussions about how abdominal fat affects a patient’s health,” says Dr. Fourman.
More Aggressive Health Screenings and Education
Patients with anthropometric-only obesity may benefit from earlier or more frequent disease screenings. Providers may also want to be more aggressive when treating prediabetes, diabetes, high cholesterol, and other conditions. Providers can also offer more intensive education about dietary and lifestyle changes that help reduce abdominal fat. “These actions may prevent someone with preclinical obesity from developing clinical obesity,” says Dr. Fourman.
Considering Pharmacologic Therapies
Most patients with anthropometric-only obesity are not currently eligible for pharmacologic therapies for obesity, which are indicated based on elevated BMI.
“We need more studies to determine whether these medications can help patients reduce fat preferentially in the abdomen and prevent the onset of clinical obesity,” says Dr. Fourman. Previous research, conducted by Dr. Fourman and others, showed pharmacologic therapies like tesamorelin, as well as lifestyle interventions, helped people with HIV-associated lipodystrophy lose abdominal adiposity without significantly affecting their overall weight.
“This new way of defining obesity presents an opportunity for clinicians to rethink care approaches and better protect the health of patients at risk of obesity-related conditions,” says Dr. Fourman.
Learn about the Metabolism Unit at Mass General
Refer a patient to the Endocrinology Division at Mass General