As we approach Healthy Weight Week in January, I recently went back over our published material relating to the subject of weight. This was both from the perspective of how many conditions can be triggered by the fact that people are no longer eating well and also, on the brighter side, that thanks to the remarkable development of new medications like Wegovy, people can quickly and effectively lose the excess poundage that these bad eating habits have caused. One common term that was shared across numerous blogs was the Body Mass Index, or BMI, often regarded as the “golden rule” for determining if someone is overweight or obese.
Now, perhaps due to the explosion of interest in the whole subject of handling obesity, there is a movement away from using the BMI as the sole diagnostic tool because scientists and healthcare providers are beginning to realize that it falls short in several respects. What’s coming out now is a shift into a more realistic and reliable measure that doctors can use to gauge whether their patients qualify for treatment of obesity, called the Body Roundness Index, or BRI.
Why is the BMI Outdated?
A person’s healthy weight depends on a wide range of individual factors and should be determined with the support of a registered dietitian or other healthcare provider who understands the individual’s particular health and nutrition needs. Unfortunately, in some local gyms and even in healthcare settings, a BMI is calculated, and the client is told they are obese, overweight, or underweight based solely on this number.
The BMI is a measurement that uses only a person’s height and weight to determine their body fat percentage. However, it does not take into account other factors such as muscle mass, bone density, or overall body composition. This means that someone who is muscular may have a higher BMI and be classified as obese, even though they are healthy and fit.
For adults, the BMI categories are as follows:
- Less than 18.5: Underweight
- 18.5 to 24.9: Healthy weight
- 25 to 29.9: Overweight but not obese
- 30 to 34.9: Obese class I
- 35 to 39.9: Obese class II
- 40 or more: Obese class III
However, a healthy BMI range might be different for some people. Generally, the healthy range is lower for people from Asian backgrounds and higher for athletes or those with more lean body tissue.
For example, let’s look at Hollywood muscleman Dwayne ‘The Rock’ Johnson. Johnson reportedly has a BMI of over 34! Vin Diesel, another very fit and muscular Hollywood star, measures in at around 27. Serena Williams has a BMI of around 28, which is also in the overweight range when body composition is not considered. My BMI is lower, and I am certainly nowhere near as fit as any of these people.
Further to that, the original model was based on the body of a 19th-century European man, not taking into account the different body compositions of other genders or ethnicities. It was never meant to be the sole diagnostic tool for determining healthy weight.
What is the Body Roundness Index?
A new formula is emerging as a potential replacement for BMI. This is the body roundness index (BRI), which has been linked to mortality risk in a study of over 30,000 US adults. BRI is calculated using a formula that involves a person’s height and waist circumference, which is more complex than BMI. Using waist measurements can better show how body fat is distributed. Fat stored around the stomach (belly fat) raises the risk of disease more than fat stored around the hips, thighs, or buttocks. This stomach fat indicates the amount of visceral fat present. New research is showing that visceral fat (aka belly fat) is the main villain. Visceral fat is deep belly fat, which can be harmful because it surrounds organs and prevents them from working properly. Measuring waist size gives a better idea of visceral fat risk than just using BMI.
What are the limitations of the BRI?
The BRI depends heavily on correct waist circumference measurement, which is both its strength and weakness. Surprisingly, measuring waist circumference can be quite difficult (Try it at home a few times and see how the results vary!) There needs to be a standard way to measure it, or else there can be significant differences even when measured by a healthcare professional.
To assess someone’s overall health, more than just relying on a single calculation is needed. Instead, a combination of different tests along with a full health history from the patient should be used. These include BMI, waist circumference, blood pressure, blood tests, and risk factors for heart disease and diabetes. Rather than switching BMI to BRI, which is only one tool for another, using multiple measures is a much better way to assess whether or not a patient or client is considered a “healthy weight.”
The name of the index is also under scrutiny. Body “roundness” may be considered a triggering term for some individuals, particularly those who have faced weight discrimination in healthcare settings in the past or are at risk of disordered eating.
The Waist to Hip Ratio (WHR)
The waist to hip ratio is another measure to determine if body fat is distributed in a healthy or unhealthy way. Measuring your waist-to-hip ratio can be done at home with a measuring tape. Studies show that the ideal waist-to-hip ratio is 0.7 for women and 0.85 for men. If your ratio is within 0.1 of the ideal, you’re likely at a low risk for health problems. However, if your ratio is higher, talking to a dietician about changing your routine is a good idea.
First, measure the narrowest part of the waist and then the hip circumference at the broadest part. Ensure the measuring tape isn’t too loose or tight on your body. Before you start measuring, inhale deeply and then exhale. Stand straight with your feet close together, arms at your sides, and weight evenly distributed. Measure right after you exhale. Measure both your waist and hips in the same unit (inches or centimeters). The waist-to-hip ratio is calculated by dividing the waist circumference by the hip circumference
Waist Hip Ratio (WHR) = waist circumference divided by hip circumference.
So, what should I focus on instead of my BMI, WHR, or BRI?
Looking ahead to Healthy Weight Week, there is a push for people to adopt healthy eating habits they can keep up with every day over the long term. The 2020-2025 Dietary Guidelines for Americans mentions different healthy eating styles like the Healthy U.S.-Style, the Healthy Mediterranean-Style, and the Healthy Vegetarian Dietary Patterns. These eating styles all focus on eating more nutrient-rich foods and drinks while staying away from too much sugar, saturated fat, and excess added salt.
Physical activity is the second component. According to the Physical Activity Guidelines for Americans, adults are encouraged to get 150 minutes of moderate exercise, like brisk walking, each week. Alternatively, they can do 75 minutes of vigorous exercise, such as jogging. It’s also suggested that adults spend at least two days a week on strength-training activities.
Other Things You Can Do To Maintain A Healthy Weight
Reduce Temptation: Relying on willpower alone isn’t the best way to maintain a healthy weight. Instead, removing unhealthy foods from home or work environments can help individuals keep up with their healthy eating goals.
Get Enough Sleep: When someone doesn’t sleep well or has irregular sleep schedules, it can lead to a poor diet. Likewise, eating unhealthy food can make it harder for a person to get good sleep.
Track Your Meals: By keeping track of their meals using photos, writing in a journal, or using apps, people are more likely to follow their healthy diet in order to maintain a healthy weight.
Find Meaningful Motivation: People who keep a healthy weight usually have motivations beyond just wanting to be thinner. Some are driven by health concerns, while others seek more energy to enjoy activities with their grandchildren. When someone sets a personal and meaningful goal, they are more likely to achieve and maintain a healthy weight.
FAQs
How is BRI calculated?
BRI is calculated using quite a complicated formula: 364.2 – 365.5 × √(1 – (waist circumference / (2π))² / (0.5 × height²)). One of the reasons BMI is stil the preferred measure may be that it’s a lot simpler to compute. Luckily, online BRI calculators are available online and easily accessible via a smartphone or computer with internet access.
What is the normal body roundness index?
For most American adults, BRI scores go from 3 or lower, indicating a lean waist, to 7 or higher, showing a rounder waist. An average score is about 5.
What is an unhealthy BRI?
Studies have found that people with a BRI of 6.9 or more had a nearly 50% higher risk of early death from high blood pressure, heart disease, diabetes, and some cancers compared to those with a BRI between 4.5 and 5.5.
