For the millions of women who spend time worrying about their weight, it's important to know what a healthy weight is rather than what is just aesthetically pleasing. While there is no one method for determining what is healthy for you, there are several calculations you can make at home to determine your ideal weight and learn whether you fall into a healthy weight.
History
The first record of calculating ideal body weight was done in 1871 by French surgeon P.P. Broca, who created a formula using height in centimeters and weight in kilograms, called the Broca's index. From this equation, it was determined that women should weigh 100 lbs. at 5 feet tall and weigh an additional 5 lbs. for every inch above 5 feet. In 1943, the Metropolitan Life Insurance company posted tables of "desirable" weights, those in the lowest mortality rate percentile. This data was not based on national averages but on information collected only by the insurance company; it was revised in 1983. In 1974, Dr. B.J. Devine published an additional recommendation for ideal body weight calculated for drug clearance rate in a hospital setting. This formula was derived from estimations, creating controversy over its accuracy.
Types of Equations
Most ideal weight equations are based off the Devine formula (ideal body weight = 50 kg + 2.3 kg per inch over 5 feet) or Broca's index. The average woman in America is 5 feet, 4 inches. Using the Devine formula, her ideal body weight is 59.2 kg, or 130.2 lbs. Most public health research is done using BMI (body mass index) instead of ideal body weight to calculate more accurately the risk of heart disease as compared to body weight. BMI is calculated by weight (kg) / height (meters) squared. A healthy range for BMI is between 20 and 25, under 18.5 is considered underweight and over 30 is considered obese.
Accuracy
Because ideal body weight is a subjective idea, most calculations are made based on incidence of disease, rather than physical appearance. BMI is the accepted gold standard in clinical research, and all equations for ideal body weight are compared to BMI and whether the middle range for each equation correlates with the middle range of BMI. Because these equations are one-size-fits-all, most are accurate only for those who fall in the middle range; they predict impossibly low weights for both very short and very tall women. Healthy weight range charts available at the Rush University Medical Center website take into account frame size (small, medium or large), but the range for each category is nearly 20 lbs., detracting from the significance of the value.
Significance
Calculating your ideal body weight may have significance only if you are interested in your risk for heart disease; however, there are so many other risk factors for heart disease excluding weight that the measure is not inclusive enough to be meaningful. Ideal body weight standards were created based on height and weight charts and do not account for fat mass as compared with muscle mass. A person who is very muscular may weight the same as someone who is overweight, but according to ideal body weight formulas, they are equally healthy. These equations and charts also were created several decades ago, when weight distribution in the United States was significantly lower; therefore, your ideal body weight will not be informative as to where you stand compared with the average American woman today.
Benefits
Using an equation for ideal body weight may be helpful for determining a healthy range for weight loss, especially if you fall significantly outside of the norm. However, these equations may project unrealistic goals if you are very short or very tall, so check with your doctor before beginning any diet program to ensure the goal you have set for yourself is healthy. If your goal is to achieve an ideal appearance, the ideal body weight equations may not be helpful.
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