Why does CHOICES use BMI as a population health indicator?

CHOICES focuses on programs and policies that can help reverse the societal and environmental conditions that drive increases in excess body weight and that emphasize healthy eating, improved physical activity, and reduced screen viewing. CHOICES use the terms “obesity” and “BMI” in certain places throughout our site and our resources when sharing direct findings from our research. Excess body weight is associated with reduced quality of life and increased risk for chronic diseases like diabetes, heart disease, and cancers,1 greater health care expenditures (Ward et al., PloS One, 2021),2 and increased mortality risk (Ward et al., eClinicalMedicine, 2022).3 Obesity is a category of excess weight defined by body mass index (BMI), which is calculated as the ratio of a person’s weight (kg) to their height squared (m2).4 BMI is used to define obesity for adults and children aged 2 years and older. Obesity is a chronic health condition recognized by the National Institutes of Health, the American Medical Association, Medicare, and Medicaid.

BMI is a useful population health indicator, although it does have limitations. BMI has been shown to be a good measure of individual-level adiposity, correlating highly (r=0.8) with gold standard measures of percent body fat, among adults, children and adolescents and for different gender and racial and ethnic groups.5,6 BMI is relatively simple to collect and easy to calculate, and it is used widely in medical and scientific research to measure population health.

However, weight stigma occurs when people are blamed for their weight. Weight stigma can increase a person’s risk of engaging in unhealthy eating behaviors and low levels of physical activity and can reduce both the quality of health care a person receives and their utilization of care, all undermining public health.7 CHOICES evaluates the cost-effectiveness of policies and programs aimed at improving nutrition and physical activity environments, promoting related health behaviors, and promoting a healthy weight across all population groups and BMI levels.


      1. Centers for Disease Control and Prevention. Overweight & Obesity: Consequences of Obesity. Accessed May 16, 2022. https://www.cdc.gov/obesity/basics/consequences.html.
      2. Ward ZJ, Bleich SN, Long MW, Gortmaker SL. Association of body mass index with health care expenditures in the United States by age and sex. PLoS ONE. 2021 Mar;16(3): e0247307. doi10.1371/journal.pone.0247307.
      3. Ward ZJ, Willett WC, Hu FB, Pacheco LS, Long MW, Gortmaker SL. Excess mortality associated with elevated body weight in the USA by state and demographic subgroup: A modelling study. eClinicalMedicine. 2022 Apr;48. doi:10.1016/j.eclinm.2022.101429
      4. Centers for Disease Control and Prevention. Obesity Basics. Accessed September 13, 2023 at: https://www.cdc.gov/obesity/basics/index.html.
      5. Woolcott OO, Bergman RN. Relative fat mass (RFM) as a new estimator of whole-body fat percentage ─ A cross-sectional study in American adult individuals. Sci Rep. 2018 Jul 20;8(1):10980.
      6. Woolcott OO, Bergman RN. Relative Fat Mass as an estimator of whole-body fat percentage among children and adolescents: A cross-sectional study using NHANES. Sci Rep. 2019 Oct 24;9(1):15279.
      7. Puhl RM, Heuer CA. Obesity stigma: Important considerations for public health. Am J Public Health. 2010;100(6):1019-1028. doi.org/10.2105/AJPH.2009.159491

Last updated:  November 1, 2023