Medical professionals have long used body mass index (BMI), a measurement for human body shape determined by dividing weight in kilograms by height in meters squared, to categorize individuals as underweight, normal, overweight, or obese. BMI is used in the clinical setting to define health status and risk for disease and is also a common anthropometric measurement used in scientific research.
However, more evidence suggests that BMI may not be as accurate as another body shape measurement, waist-to-height ratio. Waist-to-height ratio is determined by dividing waist circumference by height. Experts advise that waist circumference should be no more than half the length of your height.
A recent report presented at the European Congress for Obesity from health experts out of Oxford Brookes University in London concluded that estimates of years-of-life-lost due to obesity were more accurate when waist-to-height ratio was used compared to BMI (1). Unfortunately, the more accurate measurement predicted greater years of life lost due to obesity.
Could this mean that the obesity epidemic is a greater threat than we thought? The results of this review point to “yes.”
For example, a 30-year-old man with a BMI over 40 kg/m2—the highest BMI category—has a years-of-life-lost expectancy of 10.5 years. However, using the waist-to-height measurement increases the years-of-life-lost to 16.7 years. That is more than a 50 percent increase in life lost due to obesity.
BMI became an international standard for obesity in the 1980s. The ease of use and ability to calculate without expensive machinery has made it a popular tool in both the health and research fields. However, the use of BMI has been criticized because the measurement assumes that the distribution of lean mass and adipose tissue are inexact. Because of this, BMI generally overestimates the amount of body fat on those with more lean body mass (i.e. athletes) and underestimates excess body fat on those with less lean body mass.
A 2008 study that examined more than 13,000 subjects from the United States’ third National Health and Nutrition Examination Survey (NHANES III) found that BMI-defined obesity (BMI > 30) was present in 21 percent of men and 31 percent of women (2). However, when body fat percentages were used, obesity was found in 50 percent of males and 62 percent of females. The difference based on method used was striking.
These findings emphasize the importance of appropriate screening to monitor health. As one of the authors stated in a press release, “If you are measuring waist-to-height ratio you are getting a much earlier prediction that something is going wrong, and then you can do something about it.”
Be sure to ask your family physician to calculate your waist-to-height ratio during your next visit. If your doctor or you are not satisfied with where you stand afterward for long-term health, look to Isagenix to provide you with the solution you need to take back your health.
1. Ashwell M, Gunn P, Gibson S. Waist-to-height ratio is a better screening tool than waist circumference and BMI for adult cardiometabolic risk factors: systematic review and meta-analysis. Obes Rev 2012;13:275-86. doi: 10.1111/j.1467-789X.2011.00952.x
2. Romero-Corral A, Somers VK, Sierra-Johnson J et al. Accuracy of body mass index in diagnosing obesity in the adult general population. Int J Obes (Lond) 2008;32:959-66. doi: 10.1038/ijo.2008.11