Rising Obesity Rates: What to Know About the New Criteria

Health care experts often say body mass index (BMI) is an imperfect tool for diagnosing obesity. In early 2025, the Lancet Diabetes and Endocrinology Commission—including co-author Fatima Cody Stanford, MD, MPH, MPA, MBA, a Mass General Brigham obesity medicine specialist—recommended new obesity criteria that use body measurements and BMI.

“Where you carry excess fat may put you at risk for diabetes, heart disease, and other conditions,” says Lindsay Fourman, MD, a Mass General Brigham endocrinologist who cares for patients at Massachusetts General Hospital. A study in JAMA Network Open, co-led by Dr. Fourman, found that obesity rates rose by 60% under the new criteria.

“This new approach overcomes BMI limitations,” says Dr. Fourman. “It’s not all about the number on a scale, but where you carry excess fat.” Here’s a look at what the study findings might mean for you and your long-term health.

About the new obesity criteria

There are several parts to the new obesity criteria:

Body measurements

The new criteria include body (anthropometric) measurements, which can help distinguish between fat and muscle and capture where fat is distributed in the body. “Muscle is denser than fat, so a muscular person may have a high BMI and not have obesity,” says Dr. Fourman.

Body measurements include your:

• Waist size: Distance when wrapping a measuring tape around your waist, level with your belly button
• Waist-to-height ratio: Divide your waist size in inches by your height in inches
• Waist-to-hip ratio: Divide your waist size in inches by your hip size in inches (to do this, wrap a measuring tape around the widest part of your hips)

New obesity groups

The new criteria classify obesity into these categories:

• BMI-plus-anthropometric obesity: You have a BMI of 30 or higher (27.5 or higher if you’re of Asian descent), plus at least one high body measurement.
• Anthropometric-only obesity: Your BMI is below 30 (or 27.5 if Asian), but you have at least two body measurements that are high.
• Clinical obesity: You have an obesity-related health condition such as sleep apnea, joint pain, heart disease, or liver disease.
• Preclinical obesity: You have excess body fat that puts you at risk for clinical obesity, but you do not currently have an obesity-related health condition.

Health risks of having an apple shape

People who carry excess weight around their middles (apple shapes) tend to have more health problems than people who carry weight in their lower bodies (pear shapes). “Too much belly fat can lead to metabolic problems and other health issues,” says Dr. Fourman.

Anyone can have an apple shape—even people with normal BMIs. “Our research suggests that slender people with excess belly fat have similar health problems as those with high BMIs,” says Dr. Fourman. “Yet they may be less likely to get early health screenings or treatments because their weight appears to be normal.”

When researchers included body measurements, they found that as many as 1 in 4 Americans have excess belly fat despite a normal BMI, or what’s called anthropometric-only obesity. The largest increases in obesity prevalence based on inclusion of anthropometric-only obesity are seen among people older than 70 and people of Asian descent.

What to expect at the doctor’s office

It’s hard to say how soon health care providers will bring out the tape measure. But more than 70 organizations, including The Obesity Society and the American Heart Association, already endorse the new obesity criteria.

“This new way of looking at obesity opens the door for providers and patients to discuss lifestyle changes and other therapies that can prevent obesity-related health problems,” says Dr. Fourman.

People with high body measurements may benefit from:

• Health education: Your provider may offer more intensive education about lifestyle changes, including nutrition and exercise, that can help you lose belly fat.
• Health screenings: Your provider may screen and start medications earlier for conditions like diabetes, high blood pressure, and high cholesterol.
• Obesity medications: Obesity medications currently have approval for people with high BMIs. “We need more research to see if certain drugs can target and reduce belly fat without causing too much weight loss in people with normal BMIs,” says Dr. Fourman.

“This new obesity criteria can help identify at-risk patients who may not be aware that their body shape puts them at risk for health problems,” says Dr. Fourman. “We want to prevent obesity-related diseases and improve quality of life and life expectancy.”