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Ideal body weight

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  • Ideal body weight (IBW) is the weight that people are expected to weigh based on age, sex, and height. The ideal body weight today is used as a tool to calculate the dosage of most medications. There are two different formulas to determine ideal body weight; one formula for men and another for women.
  • The history of the formulas for calculating ideal body weight began in 1871 when Dr. Broca (a French surgeon) created the formula known as Broca's index. An unknown person translated Broca's formula into pounds and inches and modified it to create a formula called the simple rule. In 1974, Dr. Devine converted the simple rule from pounds to kilograms and published that formula for medical use. The Devine formula was intended for use to calculate the dosage of certain medications such as gentamicin, digoxin and theophylline. However, after its publication, the formula became much more widely used and became the most commonly used formula. In 1983, Dr. Robinson published a modification of the Devine formula; this contemporary modification is still in use today to calculate the dosage of most medications.
  • The ideal body weight calculator was discredited by all major medical institutions as a tool for measuring obesity and malnourishment in the last quarter of the 20th Century. The tool did not account for the nutritional needs of patients, especially women, when it was devised. The Devine IBW formula suggests ideal body weight values that may be too low in women, and impossibly low in shorter women. A limitation of the Robinson and Miller formulas are that they give low calculations in taller men.
  • Today Dr. Robinson's ideal body weight calculator is used for medication dosing. The tool is not used to measure rates of obesity or for a clinical diagnosis of obesity. Other tools of medication dosing may surpass the ideal body weight calculator in the future.


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Natural Standard developed the above evidence-based information based on a thorough systematic review of the available scientific articles. For comprehensive information about alternative and complementary therapies on the professional level, go to Selected references are listed below.

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The information in this monograph is intended for informational purposes only, and is meant to help users better understand health concerns. Information is based on review of scientific research data, historical practice patterns, and clinical experience. This information should not be interpreted as specific medical advice. Users should consult with a qualified healthcare provider for specific questions regarding therapies, diagnosis and/or health conditions, prior to making therapeutic decisions.