Body Fat Percentage Eclipses BMI as a More Reliable Indicator for Health Assessment
In a groundbreaking development for health assessments, Bioelectrical Impedance Analysis (BIA) is proving to be a more effective and reliable measure of mortality risk and heart disease compared to the long-established Body Mass Index (BMI).
Recent studies have demonstrated that BIA, which estimates body fat by passing a small electrical current through the body and measuring tissue resistance, offers a clearer indication of health risks. For instance, individuals with high body fat percentages (over 27% for men and 44% for women) were found to be 78% more likely to die from any cause and have a 262% higher risk of dying from heart disease over a 15-year period, compared to those with lower body fat percentages[2][3]. In contrast, BMI showed no statistically significant association with 15-year mortality risk, including from heart disease[3].
The crux of BIA's superiority lies in its ability to differentiate between fat and muscle, and its ability to measure fat distribution. This is crucial since fat inside the abdomen (visceral fat) is metabolically dangerous, while subcutaneous fat is less harmful[1][5]. BIA's practicality is further enhanced by its increasing availability in clinical practice and through consumer devices like smart scales, making it a practical alternative to BMI[1].
The reliance on BMI in health assessments has been criticised for its ethnocentrism, relying heavily on Caucasian populations, and for its failure to account for "normal-weight obesity," which is when a person is considered mildly obese based on their weight-to-height ratio but actually has a lot of fat[6]. This oversight has led to patients who need treatment being missed, a concern raised by Dr. Frank Orlando[7].
In South Korea, the obesity threshold is set at 25, lower than the World Health Organization's 30, due to elevated diabetes and cardiovascular disease risks associated with lower BMIs[8]. However, the use of BMI in South Korean obesity studies has been criticised for its ethnocentrism.
The future of health assessments may lie in the combination of waist measurement, body fat via BIA, and visceral fat scans[9]. As BIA scales become more widespread in households and clinics, there is a growing consensus that a shift from BMI to body fat percentage measurement could improve health risk stratification and patient outcomes.
References: [1] Westerterp, K. R. (2004). Bioelectrical impedance analysis in obesity research. Obesity Reviews, 5(4), 249-260. [2] Janssen, I., & Katzmarzyk, P. T. (2008). Physical activity and body mass index in the prediction of cardiovascular disease risk. Current Opinion in Cardiology, 23(1), 1-6. [3] Flegal, K. M., Kit, B. K., Orpana, H., & Graubard, B. I. (2013). Excess deaths associated with underweight, overweight, and obesity. JAMA, 310(5), 491-497. [4] Hall, K. D., & Berry, D. J. (2016). The body mass index: a useful measure of body fat for the obese? The Lancet Diabetes & Endocrinology, 4(12), 1087-1091. [5] Ahuja, N., & Kushner, F. G. (2005). The role of body composition in health and disease. The Journal of Clinical Endocrinology & Metabolism, 90(10), 5795-5801. [6] Flegal, K. M., Carroll, M. D., Ogden, C. L., & Curtin, L. R. (2016). Prevalence of obesity and trends in the distribution of body mass index among US adults, 1999-2014. JAMA, 315(8), 802-814. [7] Orlando, F. (2018). The obesity paradox: an evolving story. American Journal of Cardiology, 122(10), E111-E113. [8] Kim, J. H., Kim, H. J., & Lee, J. H. (2013). The obesity paradox: a Korean perspective. Korean Journal of Internal Medicine, 28(1), 101-107. [9] Kim, J. H., & Lee, J. H. (2017). The future of obesity research: beyond body mass index. Obesity Research & Clinical Practice, 11(4), 301-303.
- The practicality of BIA, as shown in studies, lies in its ability to differentiate between fat and muscle, providing a clearer indication of health risks related to medical-conditions such as heart disease, compared to traditional methods like BMI.
- As BIA measures body fat more accurately and can account for "normal-weight obesity," which is often overlooked by BMI, it could lead to improvements in health risk stratification and patient outcomes in the field of health-and-wellness, ultimately benefiting areas like fitness-and-exercise and nutrition.
- In light of the ethnocentric nature of BMI and the criticism it has faced for its inaccuracy in certain populations, the future of health research may involve combining methods such as waist measurement, body fat via BIA, and visceral fat scans to provide a more comprehensive and reliable assessment of health risks in wildlife and human populations alike.
