Definition & Facts for Adult Overweight & Obesity

What are overweight and obesity?

People whose weight is higher than what is considered healthy for their height are described as having overweight or obesity.1 Overweight and obesity can increase your risk for many health problems.

Body mass index

Overweight and obesity are defined by body mass index (BMI). BMI is a measurement that uses your weight and height to estimate overweight and obesity. The table below shows BMI ranges for overweight and obesity in adults ages 20 and older.

BMI of adults ages 20 and older



18.5 to 24.9

Healthy weight

25 to 29.9



Obesity (including severe obesity)


Severe obesity

Calculate your BMI with this online tool.

How common are overweight and obesity?

A man and woman who have overweight walk in a field with a young child.
More than 2 in 5 U.S. adults have obesity.

Overweight and obesity are common among U.S. adults ages 20 and older. According to estimates based on data from the 2017–2018 National Health and Nutrition Examination Survey (NHANES)2

  • nearly 1 in 3 adults (30.7%) have overweight
  • more than 2 in 5 adults (42.4%) have obesity, including about 1 in 11 adults (9.2%) with severe obesity
  • nearly 3 in 4 adults (73.1%) have overweight or obesity


Men are more likely than women to have overweight or obesity. Among adults ages 20 and older, 77.1% of men and 69.4% of women have overweight or obesity.2 But severe obesity, or having a BMI greater than 40, is more common among women (11.5%) than men (6.9%).

Race and ethnicity

Overweight and obesity rates also vary among racial and ethnic groups. According to 2017–2018 NHANES data, obesity affects2

  • nearly 1 in 2 non-Hispanic Black adults (49.6%)
  • more than 2 in 5 Hispanic adults (44.8%)
  • more than 2 in 5 non-Hispanic White adults (42.2%)
  • more than 1 in 6 non-Hispanic Asian adults (17.4%)

Other groups

Overweight and obesity also vary among other groups. For example, obesity is more common among people in rural areas than among those who live in urban areas.3


Last Reviewed May 2023
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This content is provided as a service of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), part of the National Institutes of Health. NIDDK translates and disseminates research findings to increase knowledge and understanding about health and disease among patients, health professionals, and the public. Content produced by NIDDK is carefully reviewed by NIDDK scientists and other experts.