Do BMI Measurements Apply to Everyone?
BMI, or body mass index, is a standard measure of overall health. BMI has been used to measure overall health since the early 1800s. To calculate BMI, divide a person’s weight in kilograms by their height in meters squared. A BMI of over 25 is overweight, and a BMI of over 30 signals obesity.
However, recent studies have shown that body mass index may not be an accurate predictor of health, especially for African Americans and other minority groups. BMI tends to overestimate body fat in African Americans, leading to inaccurate diagnoses of obesity and other health problems. In addition, BMI doesn’t consider physiological factors such as bone density. It also doesn’t differentiate between body fat and lean muscle mass, leading to inaccurate health assessments.
A reasonably simple measure to determine obesity besides BMI is to measure a person’s waist-to-hip ratio. A high waist-to-hip ratio indicates a higher risk for obesity and other health problems. An abdominal circumference of over 40 inches for men and 35 inches for women is a sign of obesity. Another way is to calculate body fat percentage. Unlike body mass index, body fat percentage considers bone density and muscle mass factors. To calculate body fat percentage, divide the total weight of fat tissue by the body’s total weight.
Some medical groups like the American Society for Nutrition and others promote other supplements to BMI that would consider factors such as race and ethnicity. Here is a list of alternative and better methods for measuring fat and mass.
Air Displacement Plethysmography (ADP)
ADP is a newer method for measuring body fat composition. This approach uses air displacement to calculate the volume of the body. ADP is not as accurate as underwater weighing or BIA, but it is more affordable and straightforward. Therefore, it is becoming increasingly popular.
Body adiposity index (BAI)
BAI is a newer method for measuring body fat composition. This approach uses ultrasound to measure the thickness of a layer of fat at six different points on the body. BAI is not as accurate as underwater weighing or BIA, but it is more affordable and more accessible to use than either of those methods. Therefore, it is becoming increasingly popular. To obtain BAI divide the waist circumference by the height.
Bioelectrical Impedance Analysis (BIA)
Bioelectrical Impedance Analysis (BIA) is another standard method for measuring body fat composition. This technique uses a small electrical current to measure body tissues’ impedance or opposition to flow. BIA is not as accurate as underwater weighing, but it is more affordable and easy to use. For this reason, fitness assessments and weight-loss programs use this method.
Calipers
Calipers are an easy and inexpensive way to measure body fat composition. This approach involves using a pair of calipers to measure the thickness of the skin fold at various points on the body. While this method is not as accurate as underwater weighing or BIA, it is more affordable and more accessible to use than either of those methods.
Dual-energy X-ray Absorptiometry (DEXA Scan)
A DEXA scan, considered the gold standard, is a more accurate way to measure body composition. This approach uses X-rays to measure the density of bone, muscle, and fat. DEXA scans are not as standard as some other methods discussed here, but they are becoming more popular because they are very accurate. Unfortunately, of all the methods mentioned, a DEXA Scan is by far the most expensive.
Hydrostatic Weighing
Underwater weighing, also known as hydrostatic weighing, is a more accurate measure of body fat composition. Your weight is taken while being completely submerged in water. The specialist then compares your weight to your displacement of water, which helps to calculate the percentage of body fat. Researchers and professionals in the fitness industry often use this method because it is so accurate.
It should be clear that body mass index may be suitable as an initial screen, but other factors should be considered, such as waist circumference. It may not be time to get rid of the BMI just yet, but using it in conjunction with other methods should yield better results than using BMI alone. Many of the above-referenced methods range from relatively inexpensive (calipers) to expensive, such as a DEXA Scan.
Here are three companies that provide body composition testing.
Cenegenics
Fit3D Proscanner
Fitnescity
