BODY MASS INDEX (BMI)Is BMI Obsolete? The Body Mass Index (BMI) is a value placed on the relationship between an individual’s height and weight. BMI value is based on a simple paradigm with respect to health and risk for disease. If there are two individuals of equal height and one individual is significantly heavier, the BMI will indicate a greater risk for poor health for the heavier person. From its inception the Body Mass Index has been questioned in its ability to accurately predict health risks and estimate body fat. The BMI has numerous flaws. For one, it fails to account for the lean body mass and fat mass ratios in assessing healthy weight. The upside to BMI, however, and the primary reason why it remains a mainstream tool for healthcare professionals has everything to do with its simplicity in comparison to other measurements such as body fat testing, or anthropometrics. There may be a new option on the horizon. In a study recently published in the journal Pediatrics, researchers from the University of Michigan determined that a child’s neck circumference was equally effective as a predictor of disease in adulthood as the waist measurement and BMI. In an interview with the researchers, the authors suggest that one major drawback of using BMI is that it does not address abdominal adiposity directly whereas neck measurements are directly linked to waist measurements. Additionally, the reliability of repeat measurements for the neck is greater than the waist measurement, because experts continue to disagree on the best point to record the waist measurement. For example, ACSM uses the smallest measure between the sternum and the navel, however, that value can often be deceptive if the individual carries most of his/her abdominal fat below the navel. This is an original study. Hence, neck circumference and risk stratification charts are not currently available. However, you should expect to see these become available in the near future. In the meantime, if you choose to measure BMI follow the formula below. Body Mass Index Formula The Body Mass Index uses your body height and weight. The BMI formula is: BMI = Your Weight in pounds / (Your Height in inches)2 x 703 For example, a person who weighs 220 pounds and is 6 feet 3 inches tall has a BMI of 27.5.
Or use the Body Mass Index Calculator The standard weight status categories associated with BMI ranges for adults are shown in the following table:
BMI is just one way of determining whether you are at risk for weight-related health problems. It is highly recommended that you have your percentage of body fat measured by one of several methods available including calipers, bio electrical impedance and underwater weighing. To use the table, find the appropriate height in the left-hand column labeled Height. Move across to a given weight (in pounds). The number at the top of the column is the BMI at that height and weight.
It is important to remember that BMI is not a direct measure of body fatness and that BMI is calculated from an individual’s weight which includes both muscle and fat. As a result, some individuals may have a high BMI but not have a high percentage of body fat. For example, highly trained athletes may have a high BMI because of increased muscularity rather than increased body fatness. Although some people with a BMI in the overweight range (from 25.0 to 29.9) may not have excess body fatness, most people with a BMI in the obese range (equal to or greater than 30) will have increased levels of body fatness. It is also important to remember that weight is only one factor related to risk for disease. If you have questions or concerns about the appropriateness of your weight, you should discuss them with your healthcare provider. |
