Why BMI Is No Longer The Only Measure of Health

If you’re on a GLP-1 medication like semaglutide (Ozempic/Wegovy) or tirzepatide (Mounjaro/Zepbound), you may be wondering how to track your progress on your weight loss journey. If you’re not losing weight, you may worry that you’re not making progress. The scale doesn’t tell the whole story!

But what can you use instead of BMI? Three of the common BMI alternatives rely on body measurements rather than weight and height alone: Body Roundness Index, Body Fat Percentage, and Waist-to-Height ratio.

What is the Body Roundness Index? (BRI)

Some scientists suggest measuring Body Roundness Index (BRI). This equation considers height, weight circumference, and hip circumference. BRI runs from 1 to 20, with higher numbers indicating a rounder body. BRIs higher or lower than the range of 4.4-5.4 have been shown to correlate with an increased likelihood of all-cause mortality, a term which refers to death for any reason. 

What is Body Fat Percentage?

A second alternative to tracking BMI is measuring body fat percentage. This used to require calipers, DEXA scans, or giant tanks of water, but not anymore! There are many commercially available scales which report body fat percentage, and apps or websites which calculate your body fat percentage from measurements of different parts of your body. According to the American Council on Exercise, 21-32% body fat is the healthy range for women. For men, the healthy range is 14-24%.

What Is The Waist-to-Height Ratio?

A third alternative to BMI is measuring your waist-to-height ratio. This compares height with the circumference of the waist. Many guidelines consider a waist-to-height ratio below 0.5 to be associated with lower cardiometabolic risk, though the right target depends on the individual. A study in 2025 showed that waist-to-height ratio is a better predictor of heart disease risk than BMI.

Which Alternative to BMI Is Most Accurate?

The truth is, No single measurement tells the complete story of your health, and that's actually the point. BRI accounts for body shape. Body fat percentage gives you a direct look at your body composition. And waist-to-height ratio measures central obesity, which has the strongest ties to cardiovascular risk of the three. So far, studies show that waist-to-height ratio and body fat percentage are slightly stronger at predicting metabolic outcomes than BMI. But it ultimately depends on your goal. That’s why many health experts now say it’s best to use multiple metrics at once.

How Providers Use Multiple Health Metrics Together

Remember that your healthcare provider is taking all these metrics (and more) into consideration. For example, they might look at your BMI in combination with your waist circumference, blood pressure, blood glucose, cholesterol levels, and body fat percentage to assess your overall cardiometabolic health. This is especially important for patients taking weight loss medications like a GLP-1. You may see improvements in blood glucose and blood pressure even before you see results on the scale. So your provider may be tracking progress that you’re not. If you want to know which metrics your provider is using to measure your success, it’s a good idea to ask them at your next visit.

BMI Alternatives: Key Takeaways

For decades, BMI has been an easy go-to metric for assessing health. But it was never meant to predict individual health outcomes (it was originally used as a population-level statistic). Alternatives like Body Roundness Index, body fat percentage, and waist-to-height ratio can offer valuable insights into what’s really going on inside your body as you lose weight on a GLP-1 medication. The real bottom line? Progress rarely shows up as just one number. By tracking multiple metrics over time and communicating with your provider, you’ll have the most inspiring and accurate picture of your progress.

If you're wondering how to track the changes in your body on a GLP-1, consider taking measurements along your journey! Losing inches indicates that you're losing body fat, even if your weight stays the same! Tracking changes in measurements can show progress that you're making, even if overall body weight isn't dropping every week. Building healthy habits like regular measurement tracking, following a weight loss diet that works for your lifestyle, and developing a healthy relationship with food can all support your journey. Talk with your healthcare provider about which measurements, if any, are appropriate for your situation.

Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult with a qualified healthcare provider before starting, stopping, or changing any medication or treatment plan.

References:

1. Thomas, D. M., Bredlau, C., Bosy-Westphal, A., Mueller, M., Shen, W., Gallagher, D., Maeda, Y., McDougall, A., Peterson, C. M., Ravussin, E., & Heymsfield, S. B. (2013). Relationships between body roundness with body fat and visceral adipose tissue emerging from a new geometrical model. Obesity, 21(11), 2264–2271. https://doi.org/10.1002/oby.20408

2. Potter, A. W., Chin, G. C., Looney, D. P., & Friedl, K. E. (2024). Defining overweight and obesity by percent body fat instead of body mass index. The Journal of Clinical Endocrinology & Metabolism, 110(4), e1103–e1107. https://doi.org/10.1210/clinem/dgae341

3. Mendes, T. B., Generoso, G., Fabiano, R. C., Halpern, B., Janovsky, C. C. P. S., Romero, C. M., Santos, R. D., Bensenor, I., Lotufo, P. A., & Bittencourt, M. S. (2025). Waist-to-height ratio and coronary artery calcium incidence: the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil). The Lancet Regional Health - Americas, 52, 101281. https://doi.org/10.1016/j.lana.2025.101281