About 40% of American adults are obese. The most recent federal data, collected from August 2021 through August 2023, puts the figure at 40.3%. That translates to roughly 4 in 10 adults aged 20 and older carrying enough excess weight to meet the clinical threshold for obesity, which is a body mass index (BMI) of 30 or higher.
How Obesity Is Defined
BMI is calculated from a person’s height and weight. It’s an imperfect measure that doesn’t account for muscle mass or where fat is stored, but it remains the standard tool used in national surveys. The CDC breaks adult weight status into several categories:
- Overweight: BMI of 25 to 29.9
- Class 1 obesity: BMI of 30 to 34.9
- Class 2 obesity: BMI of 35 to 39.9
- Class 3 (severe) obesity: BMI of 40 or higher
For children and teens, the threshold is different. A child is considered obese if their BMI falls at or above the 95th percentile for others of the same age and sex.
How the Rate Has Changed Over Time
The obesity rate in 1999–2000 was 30.5%. By the 2017 to early 2020 period, it had climbed to 41.9%. Severe obesity nearly doubled over the same stretch, rising from 4.7% to 9.2%. That two-decade surge represents one of the most significant shifts in American public health.
Interestingly, the pace of increase appears to have slowed. From 2013–2014, when the rate was 37.7%, through the most recent 2021–2023 cycle at 40.3%, the change was not statistically significant. Whether this represents a true plateau or a temporary leveling-off remains an open question.
Rates by Race and Ethnicity
Obesity does not affect all demographic groups equally. Based on 2017–2018 data, the prevalence among non-Hispanic Black adults was 49.6%, the highest of any group. Hispanic adults followed at 44.8%, and non-Hispanic white adults at 42.2%. Non-Hispanic Asian adults had a notably lower rate of 17.4%. These gaps reflect longstanding disparities in access to affordable healthy food, neighborhood walkability, healthcare, and other structural factors.
The Income and Education Connection
Obesity rates tend to be higher among people with lower incomes and less education, though the pattern is more nuanced than a simple “poorer means heavier” narrative. Among women, the relationship is clear: 45.2% of women in the lowest income bracket were obese compared with 29.7% of women in the highest bracket. For men, the picture is less straightforward. Men in the lowest and highest income groups actually had similar rates (31.5% and 32.6%), while middle-income men had the highest prevalence at 38.5%.
Education shows a more consistent pattern. College graduates had an obesity rate of about 28%, compared with roughly 40% among adults with some college and 40% among those with a high school diploma or less. But even these trends don’t hold across every group. Among non-Hispanic Asian women and men and Hispanic men, education level made no significant difference in obesity rates. Among non-Hispanic Black men, the highest-income group was actually more likely to be obese (42.7%) than the lowest-income group (33.8%).
Childhood Obesity
About 1 in 5 American children and adolescents, roughly 14.7 million kids aged 2 to 19, are obese. The overall rate from 2017 to early 2020 was 19.7%, but it varies sharply by age. Among children aged 2 to 5, the rate was 12.7%. It jumped to 20.7% for kids aged 6 to 11 and reached 22.2% among teenagers aged 12 to 19. Children who develop obesity early are far more likely to remain obese into adulthood, which is part of why public health experts treat these numbers with particular urgency.
Where You Live Matters
Obesity rates vary dramatically from state to state. According to the most recent Behavioral Risk Factor Surveillance System data, the five states with the highest adult obesity rates are West Virginia (41.4%), Mississippi (40.4%), Louisiana (39.2%), Alabama (38.9%), and Arkansas (38.9%). On the other end, Colorado has the lowest rate at 25.0%, followed by Washington, D.C. (25.5%), Massachusetts (27.0%), Hawaii (27.0%), and New Jersey (27.7%). The gap between the highest and lowest states is more than 16 percentage points.
The Financial Cost
Obesity drives enormous medical spending. In 2016, nationwide medical costs tied to obesity and its complications exceeded $261 billion. On an individual level, people with Class 1 obesity spend roughly 1.1 times more on healthcare than those at a normal weight. For people with Class 3 obesity, costs run about 3.3 times higher. When obesity-related conditions like type 2 diabetes and high blood pressure are both present, medical costs can be up to 5 times greater than for someone with obesity alone. These costs ripple through the entire healthcare system, affecting insurance premiums and public spending alike.
Health Risks at a Glance
Obesity raises the likelihood of developing type 2 diabetes, high blood pressure, heart disease, stroke, sleep apnea, certain cancers, and joint problems. The risk increases with higher BMI categories. Someone in Class 3 obesity faces substantially greater health risks than someone in Class 1, which is why tracking severe obesity separately matters. The near-doubling of severe obesity rates since 1999 is one of the more concerning trends buried in the headline number.