Studies warn nearly 70 percent of US Adults are at risk of obesity, everything you need to know about the groundbreaking study and how to lower the risk

Nearly 70 percent of US adults could now be classified as obese under a groundbreaking new definition that goes beyond traditional BMI measurements, a striking increase from the previous estimate of about 43 percent, according to a study of over 300,000 Americans published in JAMA Network Open.

According to the ScienceDaily website, researchers found that including waist circumference and other body fat distribution measures captures millions of adults previously considered healthy, many of whom face higher risks of diabetes, cardiovascular disease, and mortality.

The rise is most pronounced among older adults, with nearly 8 in 10 over age 70 now meeting the criteria, highlighting the urgent need to rethink how obesity is identified and treated across the country.


The study found that people with anthropometric-only obesity, previously considered healthy, had higher rates of diabetes, heart disease, and mortality, with about half of all newly classified individuals meeting the criteria for clinical obesity.

What is obesity?

Obesity is a condition characterized by excessive body fat that increases the risk of serious health problems, including heart disease, diabetes, and certain cancers. It is traditionally measured using body mass index (BMI), but fat distribution and waist measurements also play a key role. Obesity can affect physical health, organ function, and overall well-being.

According to the World Health Organization, 1 in 8 people in the world were living with obesity in 2022.

What does the study say?

A new study by Mass General Brigham finds that updated obesity criteria could raise US rates from 40 percent to nearly 70 percent, with older adults and newly classified individuals facing higher health risks. They used data and criteria earlier developed by the Lancet Diabetes and Endocrinology Commission.

"We already thought we had an obesity epidemic, but this is astounding," said co-first author Lindsay Fourman, MD, Mass General Brigham Department of Medicine. "With potentially 70 percent of the adult population now considered to have excess fat, we need to better understand what treatment approaches to prioritize."

In addition to Lindsay Fourman, Mass General Brigham authors include Aya Awwad, Camille A. Dash, Julia E. Johnson, Allison K. Thistle, Nikhita Chahal, Sara L. Stockman, Mabel Toribio, Chika Anekwe, and Arijeet K. Gattu, with additional authorship by Alba Gutiérrez-Sacristán.

BMI is not accurate anymore?

Obesity has long been defined using BMI, a basic calculation of height and weight, but this measure overlooks how fat is distributed in the body; alternative metrics like waist circumference, waist-to-height ratio, and waist-to-hip ratio provide clearer insight into abdominal fat, which is closely linked to disease risk.

The new framework classifies obesity as either “BMI-plus-anthropometric” for those with high BMI and elevated measurements, or “anthropometric-only” for normal BMI with multiple high measurements, distinguishing preclinical and clinical forms and endorsed by 76+ organizations.

"Identifying excess body fat is very important as we're finding that even people with a normal BMI but with abdominal fat accumulation are at increased health risk," Fourman said. "Body composition matters; it's not just pounds on a scale."

How to lower the risk of obesity

You can lower your risk of obesity by focusing on daily, sustainable habits that support overall health:

• Eat a balanced diet: Prioritize fruits, vegetables, whole grains, lean proteins, and healthy fats while limiting ultra-processed foods, sugary drinks, and excess salt.
  
• Stay physically active: Aim for at least 150 minutes of moderate exercise per week, plus strength training to maintain muscle mass.
  
• Watch waist health, not just weight: Abdominal fat increases health risk, so monitor waist size along with overall weight.
  
• Sleep and manage stress: Poor sleep and chronic stress can disrupt hormones that regulate appetite and fat storage.
  
• Get regular health checkups: Early screening helps identify risk factors like rising waist circumference, blood sugar, or cholesterol before complications develop.