Abstract
This study examines trends in the prevalence of obesity-related measures in the US overall and by sex and age group, including weight-for-length, body mass index, and waist circumference.
The Healthy People 2030 goal for obesity prevalence is 15.5% in children and adolescents and 36.0% in adults.1 This study analyzed trends from 2013-2014 to August 2021-August 2023 in the prevalence of obesity-related measures in the US.
Methods
The National Health and Nutrition Examination Survey (NHANES) is a nationally representative interview- and examination-based survey of the US civilian, noninstitutionalized population. NHANES was approved by the National Center for Health Statistics Ethics Review Board; consent was obtained from participants 18 years and older and a parent or guardian provided consent for minors. This study included cycles from 2013-2014 to August 2021-August 2023. Operations were suspended in March 2020 due to the COVID-19 pandemic; field operations resumed in August 2021 with sample design modifications, including the removal of oversampling by race and Hispanic origin.2 No changes from past examination protocols were made to the collection of standardized body measures. The examination response rate was 68.5% during 2013-2014 and 25.6% during August 2021-August 2023.3
For children younger than 24 months, high weight-for-length was defined as at or above the 97.7th percentile on World Health Organization growth standards. For children and adolescents aged 2 to 19 years, obesity was defined as a body mass index (BMI) at or above the sex-specific 95th percentile on US Centers for Disease Control and Prevention BMI-for-age growth charts and severe obesity as at or above 120% of the sex-specific 95th percentile. For adults 20 years and older, obesity was defined as a BMI of 30 or greater, severe obesity as a BMI of 40 or greater, and high waist circumference, a proxy for central adiposity, as greater than 102 cm in men or 88 cm in women.4 Pregnant individuals were excluded.
The prevalence of each obesity-related measure was estimated overall and by sex and age group. Polynomial regression was used to assess for linear and quadratic trends, with a time term reflecting the unequal spacing and duration of survey cycles. To determine if sex, age, self-reported race and Hispanic origin (and smoking status for adults) explained overall trends, adjusted linear models were also assessed. Statistical significance was determined by a 2-sided P value of <.05.
Sample weights were used to adjust for nonresponse, noncoverage, and unequal probability of selection. Analyses accounted for the complex survey design and were conducted using R version 4.4.0 (R Foundation; including R survey package version 4.4-2), SAS version 9.4 (SAS Institute), and SUDAAN version 11.0.4 (RTI International).
Results
The total analytic sample included 41 449 participants. Sample sizes for estimates varied based on availability of body measurements. Among children younger than 24 months, high weight-for-length did not change from 2013-2014 to August 2021-August 2023. The prevalence was 8.1% (95% CI, 4.5%-13.2%) in August 2021-August 2023 (Table 1).
Table 1. Trends in Prevalence of High Weight-for-Length, Obesity, and Severe Obesity Among US Children and Adolescents, by Sex and Age Group, 2013-2014 to August 2021-August 2023a.
| 2013-2014 | 2015-2016 | 2017-March 2020 | 2021-2023 | Annual changeb | P value for trendc | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| No. | % (95% CI) | No. | % (95% CI) | No. | % (95% CI) | No. | % (95% CI) | % (95% CI) | Linear | Quadratic | |
| Children younger than 24 mo | |||||||||||
| High weight-for-length (≥97.7th percentile on World Health Organization growth charts) | |||||||||||
| Overall | 609 | 8.1 (5.8 to 11.1) |
630 | 8.9 (6.8 to 11.4) |
852 | 7.7 (5.3 to 10.8) |
238 | 8.1 (4.5 to 13.2) |
−0.04 (−0.53 to 0.44) |
.86 | .98 |
| Male | 321 | 8.2 (5.4 to 11.7) |
308 | 9.5 (6.5 to 13.4) |
448 | 9.3 (6.2 to 13.2) |
118 | 8.1 (3.3 to 16.2)d |
−0.04 (−0.71 to 0.63) |
.92 | .52 |
| Female | 288 | 8.1 (4.4 to 13.4) |
322 | 8.2 (4.6 to 13.2) |
404 | 6.0 (3.2 to 10.1) |
120 | 8.1 (3.3 to 16.1)d |
−0.04 (−0.78 to 0.70) |
.92 | .49 |
| Children and adolescents aged 2-19 y | |||||||||||
| Obesity (≥95th percentile on sex-specific CDC growth charts) | |||||||||||
| Overall | 3523 | 17.2 (14.9 to 19.6) |
3340 | 18.5 (15.8 to 21.3) |
4749 | 19.7 (17.9 to 21.6) |
2492 | 21.1 (18.7 to 23.6) |
0.44 (0.10 to 0.78) |
.01e | .67 |
| Male | 1794 | 17.2 (14.6 to 20.1) |
1696 | 19.1 (15.6 to 23.0) |
2410 | 20.9 (18.9 to 22.9) |
1253 | 23.0 (20.2 to 26.1) |
0.65 (0.25 to 1.06) |
.003 | .66 |
| Female | 1729 | 17.1 (13.8 to 20.8) |
1644 | 17.8 (15.3 to 20.6) |
2339 | 18.5 (16.3 to 21.0) |
1239 | 19.1 (15.9 to 22.5) |
0.22 (−0.24 to 0.68) |
.35 | .79 |
| 2-5 y | 843 | 9.4 (6.8 to 12.6) |
814 | 13.9 (11.6 to 16.5) |
1141 | 12.7 (10.8 to 14.8) |
503 | 14.9 (11.9 to 18.3) |
0.50 (0.11 to 0.89) |
.01 | .27 |
| 6-11 y | 1294 | 17.4 (13.8 to 21.4) |
1268 | 18.4 (14.9 to 22.3) |
1765 | 20.7 (17.9 to 23.7) |
867 | 22.1 (18.0 to 26.6) |
0.56 (−0.00 to 1.12) |
.05 | .73 |
| 12-19 y | 1386 | 20.6 (16.2 to 25.6) |
1258 | 20.6 (16.4 to 25.2) |
1843 | 22.2 (19.7 to 24.8) |
1122 | 22.9 (19.3 to 26.8) |
0.30 (−0.28 to 0.87) |
.31 | .97 |
| Severe obesity (≥120% of the sex-specific 95th percentile on CDC growth charts) | |||||||||||
| Overall | 3523 | 6.0 (4.8 to 7.3) |
3340 | 5.6 (4.0 to 7.6) |
4749 | 6.7 (5.5 to 8.1) |
2492 | 7.0 (5.8 to 8.4) |
0.15 (−0.03 to 0.33) |
.11f | .97 |
| Male | 1794 | 5.6 (4.5 to 7.0) |
1696 | 6.3 (4.3 to 8.9) |
2410 | 7.3 (5.9 to 9.0) |
1253 | 7.8 (5.5 to 10.6) |
0.24 (−0.05 to 0.54) |
.11 | .61 |
| Female | 1729 | 6.3 (4.4 to 8.6) |
1644 | 4.9 (3.2 to 7.2) |
2339 | 6.1 (4.9 to 7.6) |
1239 | 6.3 (4.6 to 8.3) |
0.05 (−0.21 to 0.31) |
.69 | .55 |
| 2-5 y | 843 | 1.7 (0.8 to 3.3) |
814 | 1.8 (0.8 to 3.4) |
1141 | 2.5 (1.5 to 4.0) |
503 | 3.4 (1.9 to 5.7) |
0.21 (−0.01 to 0.43) |
.07 | .75 |
| 6-11 y | 1294 | 4.3 (3.0 to 6.1) |
1268 | 5.2 (3.7 to 7.2) |
1765 | 6.9 (5.0 to 9.3) |
867 | 6.5 (3.9 to 10.0) |
0.26 (−0.08 to 0.59) |
.14 | .28 |
| 12-19 y | 1386 | 9.1 (7.0 to 11.5) |
1258 | 7.7 (5.0 to 11.2) |
1843 | 8.5 (6.8 to 10.5) |
1122 | 8.9 (7.1 to 11.0) |
0.03 (−0.27 to 0.32) |
.86 | .47 |
National Health and Nutrition Examination Survey data; all estimates except sample sizes are weighted.
Slope of the unadjusted linear regression model.
Calculated using polynomial regression models accounting for unequal survey cycle spacing.
Estimate does not meet National Center for Health Statistics standards for proportions (relative CI width >130%) and may be unreliable.
Adjusted model P = .004.
Adjusted model P = .08.
Among children and adolescents, overall obesity increased annually by an average of 0.44 percentage points (95% CI, 0.10-0.78 [P = .01]) to 21.1% (95% CI, 18.7%-23.6%). Obesity increased in subgroups of boys and children aged 2 to 5 years. Severe obesity did not change; the overall prevalence was 7.0% (95% CI, 5.8%-8.4%) in August 2021-August 2023.
Among adults, obesity did not change in any sex or age group, except in adults aged 40 to 59 years; the overall prevalence was 40.3% (95% CI, 36.3%-44.3%) in August 2021-August 2023 (Table 2). Severe obesity increased annually by an average of 0.23 percentage points (95% CI, 0.03-0.43 [P = .03]) to 9.4% (95% CI, 8.1%-10.9%). Severe obesity increased in subgroups of women and adults aged 40 to 59 years. The prevalence of high waist circumference was 57.6% (95% CI, 53.9%-61.2%) in August 2021-August 2023, with no significant trends. There were no significant quadratic trends in any group. Adjusted models showed similar results (Tables 1 and 2).
Table 2. Trends in Prevalence of Obesity, Severe Obesity, and High Waist Circumference Among US Adults, by Sex and Age Group, 2013-2014 to August 2021-August 2023a,b.
| 2013-2014 | 2015-2016 | 2017-March 2020 | 2021-2023 | Annual changec | P value for trendd | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| No. | % (95% CI) | No. | % (95% CI) | No. | % (95% CI) | No. | % (95% CI) | % (95% CI) | Linear | Quadratic | |
| Obesity (BMI ≥30) | |||||||||||
| Overall (unadjusted) | 5455 | 37.9 (36.1 to 39.8) |
5337 | 39.8 (36.4 to 43.2) |
8295 | 41.9 (39.4 to 44.3) |
5929 | 40.3 (36.3 to 44.3) |
0.26 (−0.22 to 0.73) |
.29e | .09 |
| Age-adjusted | 5455 | 37.7 (35.8 to 39.7) |
5337 | 39.6 (36.1 to 43.1) |
8295 | 41.9 (39.4 to 44.3) |
5929 | 40.3 (36.7 to 44.1) |
0.27 (−0.20 to 0.74) |
.27 | .09 |
| Male (unadjusted) | 2638 | 35.2 (33.0 to 37.4) |
2583 | 38.0 (33.3 to 42.8) |
4051 | 41.6 (37.4 to 45.8) |
2680 | 39.2 (35.1 to 43.5) |
0.45 (−0.07 to 0.97) |
.09 | .06 |
| Age-adjusted | 2638 | 35.0 (32.8 to 37.3) |
2583 | 37.9 (33.1 to 42.8) |
4051 | 41.8 (37.7 to 45.9) |
2680 | 39.3 (35.6 to 43.0) |
0.46 (−0.05 to 0.97) |
.08 | .06 |
| Female (unadjusted) | 2817 | 40.5 (37.6 to 43.4) |
2754 | 41.5 (38.2 to 44.8) |
4244 | 42.1 (39.6 to 44.8) |
3249 | 41.3 (36.6 to 46.1) |
0.07 (−0.50 to 0.65) |
.80 | .49 |
| Age-adjusted | 2817 | 40.4 (37.6 to 43.3) |
2754 | 41.1 (37.8 to 44.5) |
4244 | 41.8 (39.3 to 44.4) |
3249 | 41.4 (36.9 to 46.0) |
0.09 (−0.48 to 0.65) |
.77 | .47 |
| 20-39 y | 1810 | 34.3 (31.1 to 37.6) |
1780 | 35.7 (31.7 to 39.8) |
2489 | 39.8 (35.3 to 44.3) |
1498 | 35.5 (29.2 to 42.2) |
0.18 (−0.57 to 0.94) |
.64 | .10 |
| 40-59 y | 1896 | 41.0 (36.5 to 45.5) |
1785 | 42.8 (37.3 to 48.5) |
2765 | 44.3 (41.3 to 47.4) |
1709 | 46.4 (42.6 to 50.2) |
0.61 (0.02 to 1.19) |
.05 | .78 |
| ≥60 y | 1749 | 38.5 (35.0 to 42.1) |
1772 | 41.0 (36.9 to 45.3) |
3041 | 41.5 (38.4 to 44.7) |
2722 | 38.9 (35.6 to 42.3) |
−0.04 (−0.53 to 0.46) |
.89 | .11 |
| Severe obesity (BMI ≥40) | |||||||||||
| Overall (unadjusted) | 5455 | 7.7 (6.2 to 9.3) |
5337 | 7.6 (6.5 to 8.9) |
8295 | 9.0 (7.8 to 10.3) |
5929 | 9.4 (8.1 to 10.9) |
0.23 (0.03 to 0.43) |
.03f | .82 |
| Age-adjusted | 5455 | 7.7 (6.3 to 9.4) |
5337 | 7.7 (6.6 to 8.9) |
8295 | 9.2 (8.0 to 10.6) |
5929 | 9.7 (8.4 to 11.1) |
0.25 (0.04 to 0.45) |
.02 | .80 |
| Male (unadjusted) | 2638 | 5.5 (4.2 to 7.0) |
2583 | 5.6 (4.2 to 7.1) |
4051 | 6.4 (5.1 to 8.0) |
2680 | 6.7 (5.2 to 8.3) |
0.15 (−0.05 to 0.35) |
.15 | .79 |
| Age-adjusted | 2638 | 5.5 (4.2 to 7.0) |
2583 | 5.6 (4.3 to 7.2) |
4051 | 6.6 (5.3 to 8.1) |
2680 | 6.8 (5.5 to 8.4) |
0.16 (−0.04 to 0.36) |
.12 | .78 |
| Female (unadjusted) | 2817 | 9.7 (7.9 to 11.9) |
2754 | 9.6 (8.2 to 11.1) |
4244 | 11.4 (9.7 to 13.3) |
3249 | 12.1 (10.3 to 14.1) |
0.31 (0.04 to 0.57) |
.03 | .92 |
| Age-adjusted | 2817 | 9.9 (8.1 to 12.1) |
2754 | 9.7 (8.4 to 11.2) |
4244 | 11.7 (10.0 to 13.7) |
3249 | 12.6 (10.8 to 14.6) |
0.33 (0.06 to 0.60) |
.02 | .90 |
| 20-39 y | 1810 | 8.0 (6.3 to 10.0) |
1780 | 7.8 (6.0 to 9.9) |
2489 | 9.7 (7.7 to 12.0) |
1498 | 9.5 (7.5 to 11.9) |
0.21 (−0.08 to 0.50) |
.15 | .66 |
| 40-59 y | 1896 | 8.6 (6.2 to 11.6) |
1785 | 8.5 (6.6 to 10.7) |
2765 | 10.7 (8.9 to 12.8) |
1709 | 12.0 (9.8 to 14.4) |
0.42 (0.10 to 0.75) |
.01 | .96 |
| ≥60 y | 1749 | 5.8 (4.2 to 7.7) |
1772 | 6.3 (4.6 to 8.4) |
3041 | 6.1 (5.2 to 7.2) |
2722 | 6.6 (5.3 to 8.0) |
0.07 (−0.14 to 0.28) |
.51 | .97 |
| High waist circumference (>102 cm in men or >88 cm in women) | |||||||||||
| Overall (unadjusted) | 5210 | 56.9 (55.5 to 58.2) |
5053 | 58.9 (54.1 to 63.6) | 7981 | 59.4 (56.9 to 61.8) |
5726 | 57.6 (53.9 to 61.2) |
0.03 (−0.42 to 0.48) |
.89g | .13 |
| Age-adjusted | 5210 | 56.1 (54.6 to 57.5) |
5053 | 57.9 (53.3 to 62.5) | 7981 | 58.3 (55.9 to 60.6) |
5726 | 56.2 (52.9 to 59.5) |
−0.03 (−0.46 to 0.40) |
.89 | .13 |
| Male (unadjusted) | 2539 | 46.0 (43.7 to 48.2) |
2472 | 47.5 (41.6 to 53.4) |
3938 | 49.1 (45.3 to 52.9) |
2605 | 47.4 (43.2 to 51.6) |
0.15 (−0.39 to 0.68) |
.59 | .27 |
| Age-adjusted | 2539 | 45.6 (43.5 to 47.8) |
2472 | 47.0 (41.3 to 52.7) |
3938 | 48.5 (44.7 to 52.3) |
2605 | 46.5 (42.7 to 50.4) |
0.08 (−0.44 to 0.61) |
.75 | .28 |
| Female (unadjusted) | 2671 | 67.4 (64.7 to 70.0) |
2581 | 69.8 (65.1 to 74.3) |
4043 | 69.2 (66.6 to 71.6) |
3121 | 67.5 (62.8 to 71.9) |
−0.06 (−0.62 to 0.49) |
.82 | .22 |
| Age-adjusted | 2671 | 66.4 (63.7 to 69.0) |
2581 | 68.5 (64.0 to 72.8) |
4043 | 67.7 (65.3 to 70.1) |
3121 | 65.9 (61.9 to 69.8) |
−0.12 (−0.64 to 0.40) |
.66 | .21 |
| 20-39 y | 1757 | 44.5 (41.4 to 47.7) |
1706 | 46.2 (42.1 to 50.3) |
2406 | 46.5 (42.0 to 51.1) |
1461 | 43.9 (38.7 to 49.3) |
−0.11 (−0.75 to 0.53) |
.74 | .31 |
| 40-59 y | 1836 | 59.7 (56.5 to 62.9) |
1708 | 62.7 (56.4 to 68.7) |
2687 | 63.6 (60.1 to 66.9) |
1658 | 61.8 (57.8 to 65.6) |
0.18 (−0.37 to 0.73) |
.52 | .15 |
| ≥60 y | 1617 | 70.0 (65.7 to 74.0) |
1639 | 70.4 (64.2 to 76.0) |
2888 | 69.9 (67.3 to 72.4) |
2607 | 68.5 (65.6 to 71.3) |
−0.19 (−0.70 to 0.31) |
.45 | .68 |
National Health and Nutrition Examination Survey data; all estimates except sample sizes are weighted.
Prevalence estimates overall and by sex were also age-adjusted by the direct method using 2000 projected US population.
Slope of the unadjusted linear regression model.
Calculated using polynomial regression models accounting for unequal survey cycle spacing.
Adjusted model P = .24. fAdjusted model P = .02. gAdjusted model P >.99.
Discussion
From 2013-2014 to August 2021-August 2023, there were small increases in the percentage of children and adolescents with obesity, as well as in adults with severe obesity (but not obesity). There were no other significant changes in obesity-related measures, including waist circumference. This period included the COVID-19 pandemic; a study using electronic health records found a small increase in mean weight among adults during the pandemic.5
Study limitations include NHANES’ continuing decline in response rates. However, weighting methods adjusted for nonresponse bias and an assessment found no major sources of bias.2 Additionally, BMI is simple, inexpensive, and useful for monitoring population-level obesity trends, but does not directly measure body fat or distribution.6
Data Sharing Statement
References
- 1.US Department of Health and Human Services . Healthy People 2030 objectives and data. Accessed October 3, 2024. https://health.gov/healthypeople/objectives-and-data/browse-objectives/overweight-and-obesity
- 2.CDC National Center for Health Statistics . Brief overview of sample design, nonresponse bias assessment, and analytic guidelines for NHANES August 2021-August 2023. September 20, 2024. Accessed October 3, 2024. https://wwwn.cdc.gov/nchs/nhanes/continuousnhanes/overviewbrief.aspx?Cycle=2021-2023
- 3.CDC National Center for Health Statistics . NHANES response rates and population totals. Accessed September 7, 2024. https://wwwn.cdc.gov/nchs/nhanes/ResponseRates.aspx
- 4.Bray GA, Heisel WE, Afshin A, et al. The science of obesity management. Endocr Rev. 2018;39(2):79-132. doi: 10.1210/er.2017-00253 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 5.Freedman DS, Kompaniyets L, Daymont C, Zhao L, Blanck HM. Weight gain among US adults during the COVID-19 pandemic through May 2021. Obesity (Silver Spring). 2022;30(10):2064-2070. doi: 10.1002/oby.23511 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 6.National Institutes of Health . Clinical guidelines on the identification, evaluation, and treatment of overweight and obesity in adults—the evidence report. Obes Res. 1998;6(suppl 2):51S-209S. [PubMed] [Google Scholar]
Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Supplementary Materials
Data Sharing Statement
