For years we’ve been told that our body mass index (BMI) is the key to knowing if we’re at a healthy or unhealthy weight. But in recent years, researchers have found that your BMI doesn’t necessarily tell the full story. That’s because BMI looks at your height and weight but isn’t able to account for what is going on beneath the surface.
The number on your scale can’t tell you about your body composition, including how much muscle and fat you have or where that fat is stored. It also doesn’t give you insight into your body’s distribution of visceral fat, which is stored deep inside the abdominal cavity and wraps around organs.
A new study published in August 2026 showcased just how much BMI can miss, finding that waist circumference and waist-to-hip ratio may provide important information about cardiovascular risk that BMI alone can miss.
Related: Why tracking your BMI is becoming irrelevant
What did the new study find?
In the study, researchers analyzed data from more than 250,000 adults and compared their BMI with waist circumference and waist-to-hip ratio. They then followed participants for around 20 years, looking at their risk of nine cardiovascular outcomes, including heart attack, stroke and heart failure. Among the findings was that nearly 1 in 5 people who had a “normal” BMI also had a high waist-to-hip ratio. Their BMI put them into the normal weight category, but this group had a higher risk of several cardiovascular problems. And the difference was significant. People with a normal or overweight BMI but higher waist measurements had a 15% to 50% higher relative risk of most of the cardiovascular outcomes studied.
Another interesting finding was the fact that nearly 10% of participants who were classified as having obesity based on their BMI had lower waist measurements. They also did not have a significantly higher risk for most of the cardiovascular outcomes studied. Thus, the study suggests that adding a waist measurement to BMI may help identify people whose cardiovascular risk could otherwise be overlooked.
The findings are part of a larger shift away from relying on BMI as a standalone measure of health. In 2023, the American Medical Association acknowledged “significant limitations associated with the widespread use of BMI in clinical settings.” Instead, it suggested BMI be used in conjunction with other measures of risk, such as the measurement of visceral fat, body composition, body adiposity index, relative fat mass, waist circumference and genetic/metabolic factors.
Related: Why you should be tracking your body composition
What does your waist measurement mean?
Your waist measurement is a simple way to check to see if you are carrying excess body fat around your middle. It can also provide clues about the amount of visceral fat you may be carrying around your internal organs. Having a higher waist circumference can put you at a higher risk of conditions like heart disease and stroke.
According to the American Heart Association, women with a waist circumference greater than 35 inches and men with a waist circumference greater than 40 inches have a higher risk of cardiometabolic disease and cardiovascular disease. These larger waist measurements are also associated with a greater risk of mortality.
How to measure your waist circumference
Your waist circumference is something that you can measure easily in the comfort of your home. Here’s an easy way to do it:
- Place a flexible tape measure horizontally around your abdomen at the level of the top of your hip bones.
- Make sure the tape is snug but isn’t compressing your skin.
- Breathe out normally and take the reading at the end of your exhalation.
- Note your measurement to the nearest ⅛ inch or 0.1 cm.
It’s also helpful to know your waist-to-hip ratio
The study also looked at waist-to-hip ratio. This metric compares the size of your waist to the size of your hips. Unlike waist circumference, which looks at the size of your midsection alone, waist-to-hip ratio gives you an idea of how your body fat is distributed.
Having a higher ratio means you are carrying more of your weight around your waist compared with your hips. Like a high waist circumference, a higher waist-to-hip ratio can also put your heart more at risk. 2024 research that looked at 22 observational studies and 709,093 adults found that people with an elevated waist-to-hip ratio had nearly twice the odds of myocardial infarction compared with those with a lower ratio.
Commonly used World Health Organization (WHO) thresholds define a waist-to-hip ratio above 0.90 in men and above 0.85 in women as indicating abdominal obesity and increased metabolic risk.
To calculate your waist-to-hip ratio, measure around the widest part of your hips. Divide your waist circumference by your hip circumference to get your ratio.
Waist measurements have their limitations
Your waist circumference and waist-to-hip ratio are a great starting point for giving you a general idea of how much fat you may be carrying around your midsection, as well as how your body fat may be distributed. But when it comes to your overall health and heart risk, they can only reveal so much.
These external measurements can’t always give you an accurate look at what is going on beneath the surface or distinguish between subcutaneous fat, which sits just beneath the skin, and visceral fat, which is stored deeper in the abdomen around your internal organs. They serve as more of a general guideline that can flag when it may be worth taking a closer look at your health.
Looking beyond the tape measure
Knowing your fat distribution matters, as visceral fat has been associated with a greater risk of cardiovascular and metabolic disease. Prenuvo’s Body Composition Analysis helps measure and track visceral fat around your organs as well as subcutaneous fat, which is stored under the skin. It can also provide insight into liver fat and muscle volume, which can give you a more detailed picture of your body composition than BMI or a tape measure can provide.
This latest research highlights the connection between abdominal fat and cardiovascular risk, but it’s also important to remember that when it comes to heart health, your body composition is only one piece of the puzzle. Metrics like your blood pressure, cholesterol, blood sugar, family history and lifestyle also play a role in your cardiovascular health. Prenuvo’s Advanced Heart Health Scan also helps provide a way to check in on your heart. It uses MRI-based MyoStrain analysis to assess myocardial strain, or how well your heart muscle moves and contracts with each heartbeat. MyoStrain assesses heart-muscle motion but does not evaluate coronary plaque or blockages, predict heart-attack risk or replace standard cardiac testing.
So while it’s a good idea to be on top of your waist circumference and waist-to-hip ratio, look at these numbers more as a guide. They can tell you if you may be carrying more weight in your midsection, which can be a sign that it may be worth doing a deeper check-in on your health.
Related: What you get in your Prenuvo Body Composition Analysis Report
Ready to learn more about what’s happening inside your body? Book a call with the Patient Services Team to learn more about Prenuvo’s Body Composition Analysis and Advanced Heart Health Scan.
