Some experts believed that the body mass index (BMI) is a standard health assessment tool that is used in the vast majority of healthcare settings. According to Katey Davidson of Healthline, it has been widely criticized for oversimplification of what it means to be healthy. For decades, it has been the go-to measurement for health based on body size. Indeed, experts argue that BMI is outdated and inaccurate and that it should not be used in medical or fitness settings. But is it true? Let's explore deeper into BMI, its history, facts, and the alternatives.

The term "BMI" refers to the body mass index, which was developed in 1832 by a Belgian mathematician named Lambert Adolphe Jacques Quetelet. BMI is defined by Yvette Brazier, of Medical News today, as a measure of body size. Thus, it combines a person's weight and height, which can indicate whether a person is an appropriate weight for their height. BMI is a screening tool that can determine whether a person is underweight, has a normal weight, is overweight, or obese. If a person's BMI is outside of the healthy range, it means he/she is at high risk to developing other health issues. Obesity can cause a number of health problems, including type 2 diabetes, high blood pressure, and cardiovascular disease. On the other hand, low body weight increases the risk of malnutrition, osteoporosis, and anemia.

The BMI scale uses a mathematical formula as follows: a person's weight in kilograms divided by his/her height in meters squared. If your BMI is less than 18.5, you are underweight and may need to gain some weight. It is recommended that you seek advice from your doctor or dietitian. With a BMI of 18.5-24.9, you are at an ideal weight for your height. Maintaining a healthy weight reduces your chances of developing serious health problems. On the other hand, a BMI of 25-29.9 indicates that you are slightly overweight. For health reasons, you may be advised to lose some weight. It is ideal to consult your doctor or dietitian for immediate intervention. And lastly, a BMI of 30 or higher indicates that you are severely overweight. If you do not lose weight, your health may suffer.

What is the verdict on using BMI as a health predictor? Experts agree that BMI is not accurate enough to be used as a diagnostic tool, but it can screen for potential weight problems in adults and children, according to Yvette Brazier.  If someone has a high or low BMI, a doctor or other healthcare professionals may consider other factors, such as skinfold thickness measurements, physical activity evaluations, discussion of any family history of cardiovascular disease, and the recommendation of other appropriate health screenings.  Based on the results, the doctor or healthcare professional can make diet and exercise recommendations.

Katey Davidson went on to say that BMI only provides a "yes" or "no" answer as to whether a person is having a "normal" weight, without considering age, gender, genetics, lifestyle, medical history, or other factors.  Using BMI alone will miss other important health assessments, such as cholesterol, blood sugar, heart rate, blood pressure, inflammation levels, and may overestimate or underestimate a person's true health.  Despite the fact that one pound or kilogram of muscle weighs the same as one pound or kilogram of fat, muscle is denser and takes up less space. As a result, a person who is very lean but has a lot of muscle mass may weigh more.

BMI is still used as a primary assessment tool in all healthcare settings because it is convenient, cost-effective, and accessible, despite of many flaws. Nevertheless, there are options to BMI that may be key predictors of a person's health. Waist circumference, waist-hip ratio, and body fat percentage are other alternatives to BMI. However, BMI does not consider other aspects of health, such as age, gender, fat mass, muscle mass, race, genetics, and medical history. Furthermore, it has been noted that using it as the sole predictor for health increases weight bias and health inequities. Though BMI can be a good starting point, it should not be the only way to measure your health status.

PNFP Marie-Claire Gaas  

References:

1. Is BMI an Accurate Predictor of Health?

Written by Katey Davidson, MScFN, RD, CPT — Medically reviewed by Jillian Kubala, MS, RD, Nutrition — Updated on August 23, 2021

https://www.healthline.com/nutrition/is-bmi-accurate

2. Measuring BMI for adults, children, and teens

Medically reviewed by Natalie Olsen, R.D., L.D., ACSM EP-C — Written by Yvette Brazier on November 9, 2018

https://www.medicalnewstoday.com/articles/323622#BMI-in-children-and-teens