Most healthcare facilities have been using body mass index (BMI) as a standard assessment tool for many years. It has been their go-to method of estimating whether a person is obese or underweight. However, since this system relies solely on height and weight, it may lead physicians to the wrong conclusion that a healthy, fit individual with greater muscle mass is overweight. Conversely, a lower BMI does not necessarily mean a person is healthier.
This weight-to-height ratio has been hotly debated over the years, with an increasing number of people asking themselves, “Is BMI a useful measure of health?” It's a valid question, especially since some experts believe it's dated and that other measurements should be taken into account, as well.
What Is BMI?
According to the World Health Organization, BMI was developed by Belgian mathematician Adolphe Quetelet in 1832. Its popularity skyrocketed during the 1970s, and many physicians and other health practitioners have been using it since in order to assess their patients’ overall health.
The BMI scale relies on the following mathematical formula that determines the ideal weight for your height. You can calculate it by dividing your weight (in kilograms or pounds) by your height (in square meters):
BMI = weight (kg) / height (m²)
Here is the same formula for pounds:
BMI = (weight (lbs) / height (in²)) x 703
Once you have calculated your BMI, you can use the following chart to determine what category you are in:
- Underweight — less than 18.5 BMI (high risk of poor health)
- Normal/healthy weight — 18.5–24.9 BMI (low risk of poor health)
- Overweight — 25–29.9 BMI (low to moderate risk of poor health)
- Obese class 1 — 30–34.9 BMI (high risk of poor health)
- Obese class 2 — 35–39.9 BMI (very high risk of poor health)
- Obese class 3 — 40 or more BMI (extremely high risk of poor health)
Since the formula does not include all the important health indicators, you may be wondering what body mass index is for. Well, it does allow you to determine whether you are at high risk for obesity-related conditions, including diabetes, sleep apnea, liver disease, arthritis, high blood pressure, high cholesterol, stroke, and several types of cancer.
Therefore, if you find yourself out of the healthy range, it is advisable to talk to your physician. Many of them recommend decreasing your BMI by a point or two, as this can significantly reduce the possibility of cardiovascular diseases.
Where Does BMI Go Wrong?
Even though BMI can help you determine your risk of metabolic diseases, many healthcare workers and experts believe it shouldn't be used as the sole indicator of health, particularly because it leaves out a number of important factors essential for creating individualized care plans.
It Doesn’t Account for Age and Gender
With summer around the corner, many women are probably wondering, “What is the BMI chart for females?” Unfortunately, there is no specific answer to this question, as the chart is interpreted the same for all individuals, regardless of their gender or age.
Plus, since its origins date back to the 19th century, another question arises — how accurate is the BMI chart today? For instance, according to some of the more recent formulas (like the one developed by J. D. Robinson in 1983), men and women of the same height should weigh differently — the ideal weight for a woman of 5'5" (165 cm) is 127 lb (57.6 kg). Conversely, a man who is of the same height should weigh 136 lb (61.6 kg).
Finally, even if an older individual has a normal BMI, that doesn’t necessarily mean they are healthy, especially when we take into account their lack of activity or sedentary lifestyle.
It Does Not Account for All Races
BMI is often perceived as flawed because it fails to take into account the body diversity among different populations. For instance, it’s unable to distinguish between different ways of storing fat. Studies have shown that African-Americans store it under their skin (subcutaneously), while Asians store it around their organs. Since the latter is much more harmful, it should be considered when deciding how healthy a person is.
It Fails to Factor in Muscle Mass and Weight Distribution
High-performance athletes have a higher muscle mass percentage than the average person. Nonetheless, BMI often categorizes them as overweight, as it doesn’t take the ratio between muscle mass and body fat into account.
In addition, how accurate is the BMI chart if it doesn’t consider body shape and weight distribution? For instance, even though two people may have the same BMI, their health risks might differ, especially if one of them has a larger waist circumference. Namely, people who store their fat in this region (rather than around their hips) are at a higher risk of diabetes or cardiovascular diseases.
It Doesn’t Measure Your Overall Health
It's difficult to tell how healthy someone is by measuring only their body fat and weight. For a more detailed picture, you need specific metrics, such as blood pressure, waist size, and the levels of LDL and HDL cholesterol, triglycerides, and blood sugar. All of these factors should be considered together instead of separately, as is usually the case with BMI.
Therefore, you may be wondering, is BMI a useful measure of health? Ultimately, it may be more useful for predicting future health status rather than assessing it at present. For instance, if you are generally healthy but the BMI chart places you in the overweight category, you may be at risk of developing diabetes or cardiovascular diseases later on.
BMI can serve as a great starting point, as it can help you identify the conditions associated with being overweight or underweight, but it shouldn't be used as the sole indicator of health. Although weight and height can give healthcare professionals insight into a person's health, other factors, such as age, gender, race, genetics, bone density, fat mass, or muscle mass, need to be considered as well.
Therefore, you must gain a better understanding of your BMI, and INEVIFIT’s Eros Smart Scale can be of great assistance here. Besides the BMI scale, which can help you keep track of your fitness journey, this handy gadget also monitors 12 more key body metrics, including body fat and muscle and bone mass. Keep an eye on your progress and stay on top of your health!