Obesity
Understanding Obesity as a Public Health Indicator
How obesity is defined and measured in surveys, and the strengths and limits of BMI as a population indicator.
Beginner explanation
In population health, obesity is usually measured with body mass index (BMI): a person’s weight in kilograms divided by the square of their height in meters. For adults 20 and older, a BMI of 30 or higher is classified as obesity.[1, 2]
BMI is a screening measure, not a diagnosis. CDC stresses that it is one potential health indicator and should be considered alongside other factors when assessing an individual’s health. CDC describes BMI as used for screening, for individual health and as a population health measure.[1]
CDC describes obesity as a serious, common and costly chronic disease, and estimates that more than 2 in 5 U.S. adults have obesity.[2]
Key definitions
- Underweight
- BMI less than 18.5
- Healthy weight
- BMI 18.5 to less than 25
- Overweight
- BMI 25 to less than 30
- Obesity
- BMI 30 or greater — Class 1 (30 to <35), Class 2 (35 to <40) and Class 3 or severe obesity (40 or greater)
- Person-first language
- CDC encourages saying “adults with obesity” rather than “obese adults.”
Condition characteristics
For adults, BMI categories are the same regardless of age, sex or race. For example, for an adult who is 5 feet 9 inches tall, CDC shows 169 to 202 pounds as overweight and 203 pounds or more as obesity. For children and teens, obesity is defined differently, using BMI percentiles for sex and age.[1]
National survey data (2017–March 2020) put U.S. adult obesity prevalence at 41.9% and severe obesity at 9.2%. Obesity prevalence rose from 30.5% in 1999–2000.[2]
Risk factors
CDC reports that obesity affects some groups more than others. In 2017–March 2020, prevalence was highest among non-Hispanic Black adults (49.9%), followed by Hispanic (45.6%), non-Hispanic White (41.4%) and non-Hispanic Asian (16.1%) adults. By education, prevalence was highest among adults with a high school diploma or some college.[2]
MedEquity note: These are national, group-level patterns. They describe populations, not individuals.
Prevention and public health context
CDC describes its obesity efforts as focusing on policy and environmental strategies that make healthy eating and active living easier. CDC also connects its person-first language guidance to reducing weight bias and stigma.[1, 2]
Obesity is expensive: CDC reports annual medical costs for adults with obesity were $1,861 higher per person than for adults with healthy weight (2019 dollars), totalling nearly $173 billion.[2]
Texas data context
The PLACES obesity measure on MedEquity estimates the share of adults with a BMI of 30 or higher, calculated from self-reported height and weight. CDC excludes implausible reports (for example, heights under 3 feet or weights over 650 pounds).[3]
Like all PLACES measures, it is a modeled estimate, and CDC advises against using it to track change over time in a county.[3, 4]
Related measures on the Explore map
- Obesity among adults (modeled estimate)
Advanced material (optional)
References
- Adult BMI Categories. Centers for Disease Control and Prevention. https://www.cdc.gov/bmi/adult-calculator/bmi-categories.html (accessed 2026-10-18).
- Adult Obesity Facts. Centers for Disease Control and Prevention. https://www.cdc.gov/obesity/adult-obesity-facts/index.html (accessed 2026-10-18).
- PLACES Measure Definitions: Health Outcomes. Centers for Disease Control and Prevention. https://www.cdc.gov/places/measure-definitions/health-outcomes.html (accessed 2026-10-18).
- PLACES: Frequently Asked Questions. Centers for Disease Control and Prevention. https://www.cdc.gov/places/faqs/index.html (accessed 2026-10-18).