Senior Health Why Do We Use BMI? 8/29/2023 | By Lori Zanteson, Environmental Nutrition There’s a lot of attention surrounding BMI (body mass index) and what has become a controversial debate of whether it should be tossed out as a health measurement. BMI is used as a guide for assessing body weight as a risk factor for health. Basically, weight and height are plugged into the BMI formula to categorize a person as underweight, normal weight, overweight, or obese. The argument against BMI is it measures weight, not fat, which makes it inaccurate, misleading, and it contributes to body shaming. To counter, it can also be a valuable component for health as a screening measurement with years of research and its resulting data surrounding it. How is BMI used? Body mass index, or BMI, has been used by doctors as part of annual physical exams for decades. It’s used to determine whether a person needs to lose weight for the benefit of long-term health, as higher BMI seemed to correlate with higher body fat. Obesity is linked with several health issues, which is why BMI is monitored. The simple calculation is weight in pounds multiplied by 703 and then divided by height in inches multiplied by height in inches. So, a person who weighs 150 pounds and is 67 inches tall (150 X 703/68 X 68) has a BMI of 23. This calculation expresses the weight to height relationship as a single number. According to the chart, a normal BMI is between 18.5 and 25; overweight is between 25 and 30; obese is over 30; and underweight is under 18.5. Limitations The relationship between weight and height does not reflect many other differences in body composition impacted by things such as muscle mass, age, gender, body frame, ethnicity or where a person carries excess body fat. In the case of muscle mass, muscle weighs more than fat, so people with more muscle mass will have a higher BMI, possibly putting them into the overweight or obese range even though they might be healthier than people with a lower BMI and less muscle mass. Similarly, women tend to have a higher fat percentage than men, and a person with a larger, heavier bone structure or a smaller, lighter bone structure, may have a less accurate BMI. Positives There are other more accurate tools to assess a person’s healthy weight and to determine body fat percentage, such as waist circumference measurement, body scans, and calipers. As a starting point for anyone concerned about their weight and related health risks, it is an accessible and potentially valuable tool. It’s simple to calculate and monitor on your own or online. For the general population, it’s relatively accurate, studies have shown correlation between body fat and future health risks, and BMI is so widely used that health care professionals have data to help with assessments. The bottom line BMI is a reasonable assessment of body fat, but it is limited in that it does not measure body fat directly. Therefore, it is not a diagnostic tool, but a measurement useful in screening and tracking weight in people in order to identify potential health risks in the future. Reprinted with permission from Environmental Nutrition, a monthly publication of Belvoir Media Group, LLC. 800-829-5384. www.EnvironmentalNutrition.com. ©2023 Belvoir Media Group. Distributed by Tribune Content Agency, LLC. Read similar articles on Seniors Guide like this: BMI May Be Misleading Read More Lori Zanteson, Environmental Nutrition Lori Zanteson writes for Environmental Nutrition, an independent newsletter written by nutrition experts dedicated to providing readers up-to-date, accurate information about health and nutrition in clear, concise English. For more information, visit www.environmentalnutrition.com.