The subject of Ideal Body Weight (IBW) has remained a hot topic issue for decades. The subject is so critical because it touches on every aspect of human health and treatment. In particular, a doctor has to know your IBW to calculate the appropriate dosage. Besides, more people have become aware of health and fitness and want to have facts about their bodies, effectiveness of fitness training and efforts towards good health.
The origin of Ideal Body Weight
The first person to focus on IBW was Paul Broca (a French Army doctor) who had to establish the IBW weight for soldiers. His discovery and publishing of the first IBW called the Broca Index opened the way for other medical experts. In his index, Broca only used the height in centimeters, and then subtracted 100 to get the normal weight. Then, 10% of the normal weight was subtracted to get the IBW. So great was his discovery that it was applied for about a full century.
The Broca Index:
Men: Ideal Body Weight (kg) = [Height (cm) - 100] - ([Height (cm) - 100] x 10%)
Women: Ideal Body Weight (kg) = [Height (cm) - 100] + ([Height (cm) - 100] x 15%)
Subsequent formulas were built on or borrowed from Broca Index
Even with the greatness of the BI, it was still considered to have very many flaws because it failed to factor other aspects that are important to IBW. For example, it does not consider the current weight, age, and environment among others.
However, even most of the subsequent formulae only repackaged the Broca Index with only a few additions.
The Devine formula which was rapidly adopted after publishing, just like Broca Index, uses height only. In his Approach, Devine argued that a man who is 5 feet should be 50 kilograms while a woman who is 5 feet should be 45.5. For every additional foot, the Ideal Body weight should be adjusted by including 2.3 kilograms.
The Devine formula:
Men: Ideal Body Weight (kg) = 50 kg + 2.3 kg per inch over 5 feet.
Women: Ideal Body Weight (kg) = 45.5 kg + 2.3 kg per inch over 5 feet.
Most of the other formulae have revolved around adjusting the ideal body weight and its adjustment. All of them use height as the primary measure.
In his formula, Robinson took the Devine formula and subjected it to empirical data. He found the base figure for ideal body weight to be different and also reviewed the adjustment for people over the height of 5 feet.
Robinson Formula:
Men: Ideal Body Weight (kg) = 52 kg + 1.9 kg per inch over 5 feet.
Women: Ideal Body Weight (kg) = 49 kg + 1.7 kg per inch over 5 feet.
The Miller formula still uses height to calculate the IBW. Just like other formulas outlined above, Miller did not include important factors that contribute to changes in body weight.
The Miller formula:
Men: Ideal Body Weight (kg) = 56.2 kg + 1.41 kg per inch over 5 feet.
Women: Ideal Body Weight (kg) = 53.1 kg + 1.36 kg per inch over 5 feet.
Including other factors in IBW and latest Body Mass Index (BMI)
Unlike other IBW formulae, Hamwi GJ deviated to factor the body frame. The formula came very close to giving an acceptable range. However, its assimilation was not as intensive as the case of Devine. This has often been picked by critiques who argue that many people who apply IBW are slow to accept changes.
The Hamwi formula:
Men: Ideal Body Weight (in kilograms) = 48 kg + 2.7 kg for each inch over 5 feet
Women: Ideal Body Weight (in kilograms) = 45.5 kg + 2.2 kg for each inch over 5 feet.
If the wrist is 7 inches, the IBW remains the way it is. However, if the wrist size is more or less than 7 inches, you add or subtract 10% of ideal body weight respectively.
Another change that came close to including new aspects of a human system to calculate IBW was the Lemmens Formula of 2005. Lemmen's formula requires you to establish the height in meters, square it, and then multiply with 22. While the formula is no doubt easy to apply, Lemmens did not explain how aspects such as weight, age, and others are catered for. This leaves it hanging in the balance with medical practitioners preferring the former.
Lemmens formula:
The final formula, The Health BMI index has created a new way to look at the ideal body weight. It factors all the previous formulae and tries to adjust for current body weight. Indeed, BMI further extrapolates what the figures (below or above a healthy BMI) that people get mean. Today, it is the most reliable method of getting the ideal body weight whether in clinical, educational, or field settings.
BMI range formula:
BMI = mass (kg) / height^2 (meter)
Healthy Weight Range = BMI between 18.5 and 25.
References
1. Pai MP, Paloucek FP, The origin of the "Ideal" body weight equations. Ann Pharmacol 2000; 34:1066-69
2. Stehman CR, Buckley RG, Dos Santos FL, et al, Bedside estimation of patient height for calculating ideal body weight in the emergency department. J Emerg Med 2011;41:97-101
3. Matsuzawa Y, Tokunaga K, Kotani K, Keno Y, Kobayashi T, Tarui S, Simple estimation of ideal body weight from body mass index with the lowest morbidity. Diabetes Res Clin Pract 1990;10(Suppl. 1):S159-64.
4. Bhumika, S., Kathrn, S. and Clarie, B. (2006). Comparison of Ideal Body Weight Equations and Published Height-Weight Tables With Body Mass Index Tables for Healthy Adults in the United States. Nutritional Diabetics 1(3)312-319
5. Green B, Duffull S. (2002). Caution when lean body weight is used as a size descriptor for obese subjects. Clin Pharmacol Ther. 72:743–4.