NCHS Data Brief ■ No. 360 ■ February 2020

U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES

Centers for Disease Control and Prevention

National Center for Health Statistics

Prevalence of Obesity and Severe Obesity Among Adults: 

United States, 2017–2018

Craig M. Hales, M.D., Margaret D. Carroll, M.S.P.H., Cheryl D. Fryar, M.S.P.H., and Cynthia L. Ogden, Ph.D.

Key findings

Data from the National 

Health and Nutrition 

Examination Survey

● In 2017–2018, the ageadjusted prevalence of obesity 

in adults was 42.4%, and 

there were no significant 

differences between men and 

women among all adults or by 

age group. 

● The age-adjusted prevalence 

of severe obesity in adults was 

9.2% and was higher in women 

than in men. 

● Among adults, the 

prevalence of both obesity and 

severe obesity was highest 

in non-Hispanic black adults 

compared with other race and 

Hispanic-origin groups. 

● The prevalence of severe 

obesity was highest among 

adults aged 40–59 compared 

with other age groups. 

● From 1999–2000 through 

2017–2018, the prevalence of 

both obesity and severe obesity 

increased among adults.

Obesity is associated with serious health risks (1). Severe obesity further 

increases the risk of obesity-related complications, such as coronary 

heart disease and end-stage renal disease (2,3). From 1999–2000 through 

2015–2016, a significantly increasing trend in obesity was observed (4). This 

report provides the most recent national data for 2017–2018 on obesity and 

severe obesity prevalence among adults by sex, age, and race and Hispanic 

origin. Trends from 1999–2000 through 2017–2018 for adults aged 20 and over 

are also presented.

What was the prevalence of obesity among adults in 

2017–2018?

The age-adjusted prevalence of obesity among U.S. adults was 42.4% in 

2017–2018. The prevalence was 40.0% among younger adults aged 20–39, 

44.8% among middle-aged adults aged 40–59, and 42.8% among older adults 

aged 60 and over. There were no significant differences in prevalence by age 

group (Figure 1). 

NOTES: Estimates for adults aged 20 and over were age adjusted by the direct method to the 2000 U.S. Census population using 

the age groups 20–39, 40–59, and 60 and over. Crude estimates are 42.5% for total, 43.0% for men, and 42.1% for women. 

Access data table for Figure 1 at: https://www.cdc.gov/nchs/data/databriefs/db360_tables-508.pdf#1.

SOURCE: NCHS, National Health and Nutrition Examination Survey, 2017–2018.

Figure 1. Prevalence of obesity among adults aged 20 and over, by sex and age: United States, 

2017–2018 

NCHS reports can be downloaded from: https://www.cdc.gov/nchs/products/index.htm.
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Among men, the prevalence of obesity was 40.3% among those aged 20–39, 46.4% among those 

aged 40–59, and 42.2% among those aged 60 and over. Among women, the prevalence of obesity 

was 39.7% among those aged 20–39, 43.3% among those aged 40–59, and 43.3% among those 

aged 60 and over. None of the differences by age were significant.

There was no significant difference in the prevalence of obesity between men and women overall 

or by age group. 

Were there differences in the prevalence of obesity among adults by race 

and Hispanic origin in 2017–2018? 

The prevalence of obesity was lowest among non-Hispanic Asian adults (17.4%) compared with 

non-Hispanic white (42.2%), non-Hispanic black (49.6%), and Hispanic (44.8%) adults. NonHispanic black adults had the highest prevalence of obesity compared with all other race and 

Hispanic-origin groups. 

Among men, the prevalence of obesity was lowest in non-Hispanic Asian (17.5%) compared with 

non-Hispanic white (44.7%), non-Hispanic black (41.1%), and Hispanic (45.7%) men, but there 

were no significant differences among non-Hispanic white, non-Hispanic black, and Hispanic 

men (Figure 2). The prevalence of obesity was lowest among non-Hispanic Asian women 

(17.2%) compared with non-Hispanic white (39.8%), Hispanic (43.7%), and non-Hispanic 

black (56.9%) women, and prevalence among non-Hispanic black women was higher than all 

other groups.

1Significantly different from all other race and Hispanic-origin groups.

2Significantly different from men for same race and Hispanic-origin group. 

NOTES: Estimates were age adjusted by the direct method to the 2000 U.S. Census population using the age groups 20–39, 40–59, and 60 and over. Access data 

table for Figure 2 at: https://www.cdc.gov/nchs/data/databriefs/db360_tables-508.pdf#2.

SOURCE: NCHS, National Health and Nutrition Examination Survey, 2017–2018.

Figure 2. Age-adjusted prevalence of obesity among adults aged 20 and over, by sex and race and Hispanic origin: 

United States, 2017–2018 
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Non-Hispanic black women had a higher prevalence of obesity than non-Hispanic black 

men. There were no significant differences in prevalence between men and women among 

non-Hispanic white, non-Hispanic Asian, or Hispanic adults. 

What was the prevalence of severe obesity among adults in 2017–2018? 

The age-adjusted prevalence of severe obesity among U.S. adults was 9.2% in 2017–2018. 

Women had a higher prevalence of severe obesity (11.5%) than men (6.9%). The prevalence was 

highest among adults aged 40–59 (11.5%), followed by adults aged 20–39 (9.1%) and adults 

aged 60 and over (5.8%). Non-Hispanic black adults had the highest prevalence of severe obesity 

(13.8%), and non-Hispanic Asian adults had the lowest (2.0%) (Figure 3).

1Significantly different from men. 

2Significantly different from adults aged 20–39. 

3Significantly different from adults aged 40–59. 

4Significantly different from all other race and Hispanic-origin groups.

NOTES: Estimates for adults aged 20 and over were age adjusted by the direct method to the 2000 U.S. Census population using the age groups 20–39, 40–59, 

and 60 and over. Crude estimates are 9.0% for total, 6.8% for men, and 11.1% for women. Access data table for Figure 3 at: https://www.cdc.gov/nchs/data/

databriefs/db360_tables-508.pdf#3.

SOURCE: NCHS, National Health and Nutrition Examination Survey, 2017–2018.

Figure 3. Age-adjusted prevalence of severe obesity among adults aged 20 and over, by sex, age, and race and Hispanic 

origin: United States, 2017–2018

 
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What are the trends in obesity and severe obesity among adults?

From 1999–2000 through 2017–2018, the age-adjusted prevalence of obesity increased from 

30.5% to 42.4%, and the prevalence of severe obesity increased from 4.7% to 9.2%. The observed 

changes in prevalence of obesity and severe obesity between 2015–2016 and 2017–2018 were not 

significant (Figure 4).

1Significant linear trend.

NOTES: Estimates were age adjusted by the direct method to the 2000 U.S. Census population using the age groups 20–39, 40–59, and 60 and over. Access data 

table for Figure 4 at: https://www.cdc.gov/nchs/data/databriefs/db360_tables-508.pdf#4.

SOURCE: NCHS, National Health and Nutrition Examination Survey, 1999–2018.

Figure 4. Trends in age-adjusted obesity and severe obesity prevalence among adults aged 20 and over: United States, 

1999–2000 through 2017–2018

 
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Summary

The age-adjusted prevalence of obesity was 42.4%, and the age-adjusted prevalence of severe 

obesity was 9.2% among adults aged 20 and over in the United States in 2017–2018. The overall 

prevalence of obesity was similar among men and women, but the prevalence of severe obesity 

was higher among women. Adults aged 40–59 had the highest prevalence of severe obesity. 

The prevalence of obesity was highest among non-Hispanic black adults compared with 

other race and Hispanic-origin groups, overall and among women. However, among men, the 

prevalence of obesity was not significantly different between non-Hispanic white, non-Hispanic 

black, and Hispanic men. Overall, and among men and women, obesity was lowest among 

non-Hispanic Asian adults. Non-Hispanic black adults had the highest prevalence of severe 

obesity, and non-Hispanic Asian adults had the lowest.

From 1999–2000 through 2017–2018, the prevalence of obesity and severe obesity increased, but 

the observed increase in the prevalence of obesity and severe obesity between 2015–2016 and 

2017–2018 was not significant. 

Monitoring the prevalence of obesity and severe obesity is relevant for public health programs 

that focus on reducing or preventing obesity and its consequences. In the United States, the 

prevalence of obesity among adults has moved further away from the Healthy People 2020 goal 

of 30.5% (5). 

Definition

Obesity and severe obesity: Body mass index (BMI) was calculated as weight in kilograms 

divided by height in meters squared, rounded to one decimal place. Obesity in adults was 

defined as a BMI of greater than or equal to 30 and severe obesity as a BMI of greater than or 

equal to 40.
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Data source and methods

Data from the National Health and Nutrition Examination Surveys (NHANES) for the years 

1999–2000, 2001–2002, 2003–2004, 2005–2006, 2007–2008, 2009–2010, 2011–2012, 2013–2014, 

2015–2016, and 2017–2018 were used for these analyses. Data from NHANES 2017–2018 were 

used to test differences between subgroups. This 2-year NHANES survey cycle provides the 

most recent estimates of obesity. However, the precision of the estimated prevalence of obesity 

and severe obesity and the ability to detect differences in the prevalence when a difference does 

exist are lower than when these estimates are based on 4 years of data because of the smaller 

sample sizes. For these reasons, the sex-specific, 2-year estimates for severe obesity prevalence 

by age and race and Hispanic origin were not reported. In testing for trends in obesity, orthogonal 

contrasts were used with 10, 2-year cycles: 1999–2000, 2001–2002, 2003–2004, 2005–2006, 

2007–2008, 2009–2010, 2011–2012, 2013–2014, 2015–2016, and 2017–2018.

NHANES is a cross-sectional survey designed to monitor the health and nutritional status 

of the civilian noninstitutionalized U.S. population (6). The survey consists of interviews 

conducted in participants’ homes and standardized physical examinations conducted in mobile 

examination centers.

The NHANES sample is selected through a complex, multistage probability design. In 

2011–2018, non-Hispanic black, non-Hispanic Asian, and Hispanic persons, among other 

groups, were oversampled to obtain reliable estimates for these population subgroups. Race- and 

Hispanic-origin-specific estimates reflect individuals reporting only one race; those reporting 

more than one race are included in the total but are not reported separately. 

Although obesity was defined using BMI, this index does not measure body fat directly. The 

relationship between BMI and body fat depends on body composition and varies by sex, age, and 

race and Hispanic origin (7,8). Health risks may vary among different race and Hispanic-origin 

groups at the same BMI. 

Examination sample weights, which account for the differential probabilities of selection, 

nonresponse, and noncoverage, were incorporated into the estimation process. All variance 

estimates accounted for the complex survey design by using Taylor series linearization. Pregnant 

women were excluded from analyses.

Age-adjusted prevalence estimates were adjusted using the direct method to the 2000 projected 

U.S. Census population using the age groups 20–39, 40–59, and 60 and over to compare 

prevalence estimates between subgroups that differ with respect to their age distributions. 

Differences between groups were tested using a univariate t statistic at the p < 0.05 significance 

level. All differences reported are statistically significant unless otherwise indicated. 

Adjustments were not made for multiple comparisons. Data management and statistical analyses 

were conducted using SAS System for Windows version 9.4 (SAS Institute, Inc., Cary, N.C.), 

SUDAAN version 11.0 (RTI International, Research Triangle Park, N.C.), and R version 3.5.2, 

including the R “survey” package (9), to account for the complex sample design.
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About the authors

Craig M. Hales, Margaret D. Carroll, Cheryl D. Fryar, and Cynthia L. Ogden are with the 

National Center for Health Statistics, Division of Health and Nutrition Examination Surveys. 

References

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Systematic evidence review from the Obesity Expert Panel. 2013. Available from: 

https://www.nhlbi.nih.gov/sites/default/files/media/docs/obesity-evidence-review.pdf. 

2. Li TY, Rana JS, Manson JE, Willett WC, Stampfer MJ, Colditz GA, et al. Obesity as 

compared with physical activity in predicting risk of coronary heart disease in women. 

Circulation 113(4):499–506. 2006.

3. Hsu CY, McCulloch CE, Iribarren C, Darbinian J, Go AS. Body mass index and risk for endstage renal disease. Ann Intern Med 144(1):21–8. 2006.

4. Hales CM, Fryar CD, Carroll MD, Ogden CL. Prevalence of obesity among adults and youth: 

United States, 2015–2016. NCHS Data Brief no 288. Hyattsville, MD: National Center for Health 

Statistics. 2017. Available from: https://www.cdc.gov/nchs/products/databriefs/db288.htm.

5. U.S. Department of Health and Human Services. Office of Disease Prevention and Health 

Promotion. Healthy People 2020 topics and objectives: Nutrition and weight status. 2020. 

Available from: https://www.healthypeople.gov/2020/topics-objectives/topic/

nutrition-and-weight-status. 

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Examination Survey: Sample design, 2011–2014. National Center for Health Statistics. 

Vital Health Stat 2 (162). 2014. Available from: https://www.cdc.gov/nchs/data/series/sr_02/

sr02_162.pdf.

7. Deurenberg P, Deurenberg-Yap M, Guricci S. Asians are different from caucasians and from 

each other in their body mass index/body fat per cent relationship. Obes Rev 3(3):141–6. 2002.

8. Flegal KM, Ogden CL, Yanovski JA, Freedman DS, Shepherd JA, Graubard BI, Borrud LG. 

High adiposity and high body mass index-for-age in U.S. children and adolescents overall and by 

race-ethnic group. Am J Clin Nutr 91(4):1020–26. 2010.

9. RTI International. SUDAAN version 11.0 and R version 3.5.2 [computer program]. 2019.
NCHS Data Brief ■ No. 360 ■ February 2020

Keywords: body mass index (BMI) • trends • National Health and Nutrition 

Examination Survey (NHANES)

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Suggested citation

Hales CM, Carroll MD, Fryar CD, Ogden 

CL. Prevalence of obesity and severe 

obesity among adults: United States, 

2017–2018. NCHS Data Brief, no 360. 

Hyattsville, MD: National Center for Health 

Statistics. 2020.

Copyright information

All material appearing in this report is in 

the public domain and may be reproduced 

or copied without permission; citation as to 

source, however, is appreciated.

National Center for Health 

Statistics

Jennifer H. Madans, Ph.D., Acting Director

Amy M. Branum, Ph.D., Acting Associate 

Director for Science

Division of Health and Nutrition 

Examination Surveys

Ryne Paulose-Ram, M.A., Ph.D., Acting Director

Lara Akinbami, M.D., Acting Associate Director 

for Science