U.S. obesity rates rose sharply between 1999 and 2023

Obesity rates among U.S. adults and children rose sharply in recent years and by 2023, 40% of adults and 20% of youth met the criteria for obesity, according to new, independent research published today in the American Heart Association's flagship journal Circulation.

"Obesity is a leading public health concern, linked to higher risks for cardiovascular disease and premature death," said study author Anum Minhas, M.D., M.H.S., an assistant professor of medicine in cardiology at the Johns Hopkins School of Medicine in Baltimore. "Examining national trends in obesity can help determine which segments of the population may benefit the most from screening, how resources should be allocated for preventive efforts and the potential impact of implementing public health initiatives to reduce the burden of obesity." Minhas said the research is believed to be the most contemporary evaluation of obesity trends among U.S. adults and youth.

In the study, researchers defined obesity as a body mass index (BMI) of 30 kg/m² or higher (except for Asian populations where distinct race-specific cutoffs were used). Obesity can increase the risks for health conditions, including Type 2 diabetes, high blood pressure, heart disease, stroke and chronic kidney disease. Severe obesity, which study researchers defined as a BMI greater than or equal to 40 kg/m², carries the highest risks for cardiovascular disease and death.

The first ever guideline from the American Heart Association on the Prevention, Detection, Evaluation and Management of Cardiovascular-Kidney-Metabolic disease, published in June 2026, states that obesity is the first stage of cardiovascular-kidney-metabolic syndrome. The guideline emphasizes obesity management in the form of diet and lifestyle modifications as essential for a longer, healthier life.

In this study, researchers examined how rates of various levels of obesity changed over more than 20 years, according to data from the National Health and Nutrition Examination Survey (NHANES). Rates and prevalence of obesity, severe obesity and abdominal obesity were analyzed, and potential trends by age, sex, race and ethnic groups were measured.

What are the key findings of the analysis?

• Among the nearly 8,700 people in the U.S. surveyed between 1999 and 2023, including youth, defined as less than 20 years old, and adults, 20 years old and over.
• Among adults, researchers found notable increases in the prevalence of obesity (30% to 41%, respectively), severe obesity (5% to 10%, respectively) and abdominal obesity (48% to 61%, respectively) in 1999 vs. 2023.
• Among youth, researchers noted about a 30% increase for overall obesity, a 50% increase for severe obesity and a three-fold increase in abdominal obesity when comparing 1999 vs. 2023.
• Disparities in obesity prevalence were also found in the analysis, with women being more likely to have severe obesity (13%) and abdominal obesity (70%) compared to men, who were less likely to have severe obesity (7%) and abdominal obesity (51%) as of the last time data was taken in 2023. The gap between women and men could be due to women having more hormonal differences and changes throughout their lives than men, researchers noted.
• Throughout the period studied, non-Hispanic Black people consistently had the highest prevalence of all obesity compared to all other demographic groups.

These findings have major implications for cardiovascular disease and mortality, according to Minhas. "We must increase the availability and use of individual and population-level initiatives to target the rising epidemic of obesity and support people with obesity," she said. "This includes pursuing a better understanding of which patients could benefit most from weight loss medications or other treatments. There are several effective weight loss therapies, including GLP-1 receptor agonist medications, bariatric surgery and other treatment options, confirmed in recent studies to have a positive impact on metabolic risk factors (blood sugar, blood pressure and cholesterol levels) and cardiovascular health, approved by the FDA and recommended in evidence-based treatment guidelines."

What are the study's details, background, design and limitations?

• Between 1999 to 2023, a median of 8,687 individuals in the U.S. were surveyed through NHANES, including about 50% women. Approximately one-third of participants were youth younger than age 20 years, and two-thirds were adults ages 20 and older.
• NHANES is conducted continuously at several sites across the U.S., and the researchers analyzed participants' health information and survey responses between 1999 and 2023, including demographic, clinical and biomarker data.
• Limitations of the analysis include that participants' BMI measures were used to define obesity and classify different obesity levels. The study did not include body composition (fat mass versus lean mass) to classify participants' obesity status or levels. In addition, NHANES response rates decreased over time, which increases the chance of nonresponse bias (those who didn't respond may have had different outcomes or results from those who did continue to respond and participate in the survey, possibly skewing the results).