These are the organizations we rely on for health information. Each page on this site lists the specific pages it uses. We are not affiliated with any of these organizations.
Organizations we rely on
| Organization | What we use it for |
|---|---|
| NHS (UK) | Waist-to-height ratio and BMI calculators and guidance |
| NIDDK, National Institutes of Health (US) | Weight, BMI, waist size and body fat information |
| National Institute on Aging, NIH (US) | Healthy aging, physical activity and nutrition for older adults |
| CDC (US) | Physical activity guidance |
| World Health Organization | International guidance on health measurements and physical activity |
| MedlinePlus, US National Library of Medicine (NIH) | Plain-language health encyclopedia, including aging changes |
| Mayo Clinic | Explanatory health information, used alongside the sources above |
| Harvard Health Publishing | Explanatory health information, used alongside the sources above |
Pages cited so far
- NHS: Calculate your waist to height ratio
- NHS: Calculate your body mass index (BMI) for adults
- NIDDK: Am I at a healthy weight?
You can read how we use sources in our editorial policy.
Last reviewed: October 13, 2026.